Validation is the check that tells you whether an EPUB follows the standard. It is not a matter of opinion: a file either passes or fails, and the checker tells you where. The tool behind most checks is EPUBCheck, maintained by the standards body, and it is what Apple, Kobo, Google and many distributors run before they accept a book. Amazon runs its own checks on upload as well. A book that validates is far less likely to be rejected, and far more likely to display consistently on every device. EPUB validation is therefore the last step of any ebook build, and the first step of any rescue.
EPUB Validation · from $169
EPUB validation service that fixes every error before a store sees it
EPUB validation checks that your ebook file follows the standard that retailers expect, and a single error can cause a store to reject the book or display it badly. Our epub validation service runs EPUBCheck, explains each message in plain English, repairs the file and confirms the result in the retailer previewers. Choose a word count to see a fixed price for validating and repairing your own file.
View Pricing
Most files are validated and repaired within two working days.
- EPUBCheck errors explained and fixed
- Retailer previewer tests
- Pass guarantee on every file
Key facts
- $169Starting price for the EPUB validation, before extras
- 2 roundsOf revisions included in every EPUB validation order
- 2 to 3 daysFastest standard delivery for a short EPUB validation
Overview
What an EPUB validation actually involves
There are several levels. EPUBCheck validates the package, the HTML, the CSS and the navigation. Accessibility checkers, such as Ace by DAISY, test whether the book meets the accessibility standard. Store-specific tools, such as Kindle Previewer, check that the file converts and displays. And a human check opens the book on devices to see what the tools cannot. A complete validation covers all of them. Running a validator online takes a minute. Reading its output, understanding the codes and fixing the causes is the part that needs experience.
Our EPUB validation service runs all the checks, explains every message and fixes the causes. We deliver a validation report and, if you want, a repaired file that passes with zero errors. We can also give a written statement that the file passed, which some distributors ask for. If you only need to know where you stand, we offer a report without repairs. If you need the whole thing fixed, we do it. Either way, you learn what each error meant.
We start every EPUB validation job with an audit. We open your file or manuscript, list what is already right, what is wrong and what needs a decision from you, and send that back before any work begins with your EPUB validation. The audit is why there are no surprises: you know the scope, the price and the schedule, and you know which of EPUBCheck errors and warnings and usage notes is likely to need the most care.
Authors often look for EPUB validation online, and an online checker is a useful first test. EPUB validation for Apple Books is stricter, so we run EPUBCheck, fix every error and then test on the stores you plan to use.
Why it matters
Why an EPUB validation matters
EPUB validation shapes the reading experience
A file that fails validation may still open in one reader and fail in another. Readers rarely name the cause, but they feel the difference between careful and careless EPUB validation work. The effect is cumulative: each small decision in EPUB validation supports the next, so the book gains authority page by page.
The details carry the quality
Retailers run their own validators that add rules. Each detail in EPUB validation has a tolerance, and a professional knows where it lies and how to check it. None of this is visible when it is done well, which is exactly why careful EPUB validation work is easy to undervalue.
Doing it once, properly, saves time
Accessibility checks are increasingly required. Getting EPUB validation right at the start also keeps later edits, reprints and new editions inexpensive. It is far easier to get EPUB validation right while the book is still a working file than to repair it after publication.
Validation done the way retailers check
EPUB and HTML validation
Validation begins with EPUBCheck, the reference checker for the format, and then goes beyond it. The tool confirms that the package, the navigation and the content documents follow the standard, and we add the checks that matter to stores: image sizes, metadata, links and the way each retailer renders the book.
The how to validate an epub file question has a simple first answer, which is to run EPUBCheck and read the report. A real epub validation tool is only the start, because someone has to understand the messages, change the source and run the check again, which is what we do for each file.
If your project needs epub accessibility validation, we also run the accessibility checks that matter to publishers, covering structure, alternative text and metadata. For authors who want certainty, our epubcheck pass guarantee means that the delivered file reports no errors, and we continue the work until it does.
- EPUBCheck run and every message explained
- Errors repaired in the source, not hidden
- Retailer previewer checks after validation
Choose the right build
The first decision in any EPUB validation
Validate and report
A check with a written report. We choose this route when the book leans on ePUBCheck errors, and we show a sample before the whole EPUB validation job proceeds. For a EPUB validation, we show a sample of each route where it helps, so you can choose from evidence rather than from a description.
Validate and repair
A check plus fixes. We choose this route when warnings and usage notes are central to how the book is used, and we explain the cost and schedule consequences before you commit. For a EPUB validation, we show a sample of each route where it helps, so you can choose from evidence rather than from a description.
Specification
The EPUB validation specification we build to
These are the decisions we make on every EPUB validation job, and the reason for each one.
Element
How we build it
Why it matters
EPUBCheck
Zero errors. We confirm the value with you before building, and record it in the specification for your EPUB validation job.
Meets the standard. Getting this right early avoids rework once the EPUB validation pages have been proofed.
Warnings
Fixed or explained. We apply it through a defined style or setting, so it holds across the whole EPUB validation file.
No mystery. For a EPUB validation, readers and reviewers notice when it is wrong, even when they cannot say what is wrong.
Accessibility
Reading order and alt text checked. We verify it again in the final proof, because it is easy to disturb during late edits on this EPUB validation project.
Required by some buyers. With your EPUB validation, platforms and printers check it automatically, and a failure delays the launch.
Retailers
Their validators run. For a EPUB validation, where your platform sets a different rule, we follow the platform and tell you why.
Accepted at upload. It also keeps later editions of the EPUB validation work consistent with the first.
Files
A validated EPUB, a validation report and a fix list, named consistently and delivered with a short specification.
For a EPUB validation, a clear package prevents mix-ups between versions and speeds up any later change. Getting this right early avoids rework once the EPUB validation pages have been proofed.
Checks
Preflight or validation run on every deliverable, with the report supplied for the EPUB validation. We apply it through a defined style or setting, so it holds across the whole EPUB validation file.
For your EPUB validation, evidence of a clean pass is what separates a checked file from a hopeful one. For a EPUB validation, readers and reviewers notice when it is wrong, even when they cannot say what is wrong.
See what it costs
See the price of your EPUB validation in a minute
Choose a word count to see what it costs to validate and repair your own EPUB, with the delivery estimate shown before you commit to anything.
Build my priceProcess
How an EPUB validation project runs
Send
You send the files and tell us what you need from the EPUB validation job, including where you plan to publish and any deadline. For a EPUB validation, we confirm the scope and the price. You are never left guessing what comes next, because we confirm each stage of the EPUB validation job in writing.
Day 1
Audit
We examine the file, list what is correct and what must change, and send a short note with any decisions we need from you on this EPUB validation project. If something unexpected turns up at this stage, we tell you at once and agree the fix before continuing for the EPUB validation.
Days 1 to 2
Plan
We agree the specification, including how we will treat EPUBCheck errors and warnings and usage notes, and confirm the schedule. On this EPUB validation job, this stage is where most questions arise, so we leave time for them in the schedule.
Day 2
Build
For a EPUB validation, we carry out the work, applying defined styles and settings, and fixing faults at their source rather than covering them. You are never left guessing what comes next, because we confirm each stage of the EPUB validation job in writing.
Days 3 to 7
Check
For your EPUB validation, we validate, preview and review the result against the specification, and compare the text with your manuscript. If something unexpected turns up at this stage, we tell you at once and agree the fix before continuing for the EPUB validation.
Days 8 to 9
Deliver
With your EPUB validation, you receive the files, the specification and the change log, with support if a platform queries the file. On this EPUB validation job, this stage is where most questions arise, so we leave time for them in the schedule.
Day 10
Before and after
An EPUB before and after validation
The same ebook with an EPUBCheck report before and after repair. The story is unchanged, and the second file is the one a store accepts.
123Before
- 1A report with errors and warnings
- 2Navigation links that point to missing files
- 3Images without alternative text or with the wrong type
123After
- 1A clean report with no errors
- 2Navigation that links correctly to every chapter
- 3Images with the right type and alternative text
- 3problems found in the first review
- 3fixes checked in the final review
- 1named specialist owning every fix
- Fixedprice confirmed in the calculator before you order
A file stores accept
A clean report removes the most common cause of rejection.
A better reading experience
Fixed navigation and images work on every device.
Peace of mind
You know exactly what was wrong and what was fixed.
Pricing calculator
Build your EPUB validation price
Retailers run an automatic checker on every EPUB, and a single error can bounce the upload. Send us the file you have, choose what you want back and see the fixed price for validating and repairing it until it passes.
Beyond our online limit? Let us quote it properly.
An EPUB above 150,000 words, or with more than 150 images, is quoted individually. Send us the file and a specialist replies with a fixed price and a delivery date.
The price covers validating, repairing and re-testing the EPUB. Rewriting content, redesign and retailer fees are not included.
Price guide
EPUB Validation cost at a glance
The table lists the epub validation cost by length, with the base price, delivery time and the kind of file that fits each tier. The calculator adds extras to your EPUB validation for an exact total.
Word count
Base price
Standard delivery
Typical book
Very short text
$169
2-3 working days
Very short text
Short text
$209
3-4 working days
Short text
Compact text
$259
3-5 working days
Compact text
Short book
$329
4-6 working days
Short book
Standard length
$399
5-7 working days
Standard length
Full-length text
$469
5-8 working days
Full-length text
Long text
$539
6-9 working days
Long text
Large text
$619
7-10 working days
Large text
Longest online length
$689
8-11 working days
Longest online length
More than 150,000 words
Custom quote
Agreed with your quote
Quoted individually
Comparison
EPUB Validation compared with the alternatives
What you compare
A quick EPUB validation fix
Professional EPUB validation
Approach
A quick fix treats symptoms and leaves the cause in the file in this EPUB validation order. That approach saves effort at the start and tends to cost more in repairs once the EPUB validation job is live.
A professional EPUB validation job finds and corrects the cause. We do this as standard on every EPUB validation job, and the evidence comes with your files.
Consistency
Manual changes vary from page to page with your EPUB validation. It leaves the cause in place, so the same fault tends to return when the text changes on this EPUB validation project.
Defined styles apply identically everywhere. For a EPUB validation, it is built to be repeated, so later editions cost less and match the first.
Validation
For a EPUB validation, success is judged by eye on one screen. It is hard to check, so faults are usually found by readers instead of by the author on this EPUB validation project.
Success is judged by the platform's own checks and real devices on this EPUB validation project. On this EPUB validation job, it is checked by a person and by software before it reaches you, so problems are found early.
Documentation
Nothing is recorded, so the next edition starts again on this EPUB validation project. That approach saves effort at the start and tends to cost more in repairs once the EPUB validation job is live.
A specification and change log are supplied for the EPUB validation. We do this as standard on every EPUB validation job, and the evidence comes with your files.
Risk
A rejected upload costs days and may delay a launch for the EPUB validation. It leaves the cause in place, so the same fault tends to return when the text changes on this EPUB validation project.
For your EPUB validation, files are tested before they reach you, and fixes are covered by the guarantee.
Cost
Cheap at first, then repeated whenever something changes in this EPUB validation order. It is hard to check, so faults are usually found by readers instead of by the author on this EPUB validation project.
For your EPUB validation, a fixed price and a reusable result. On this EPUB validation job, it is checked by a person and by software before it reaches you, so problems are found early.
Our standard
The standard we hold every EPUB validation to
Fix causes, not symptoms
Our EPUB validation work corrects the underlying structure, so the same problem does not return when the text changes. It is a standard we hold on every EPUB validation job, whatever the price of the package or the length of the book.
Evidence over assurance
With your EPUB validation, we supply the validation or preflight report with your files, so a clean result is something you can see. With your EPUB validation, you can check it for yourself, because the evidence comes with your files. With your EPUB validation, holding to it costs us time, and it saves you the cost of repairs later.
Plain communication
We explain what we found and what we did in plain language, and we tell you honestly when something is outside what the file can support on this EPUB validation project. With your EPUB validation, holding to it costs us time, and it saves you the cost of repairs later.
Checklist
The pre-delivery checklist for an EPUB validation
Every item below is verified on your EPUB validation before it leaves our desk.
- Audit completed and agreed with you
- EPUBCheck errors checked and corrected
- Warnings and usage notes checked and corrected
- Accessibility checks checked and corrected
- Retailer rules checked and corrected
- Validation or preflight run with the report supplied
- Previewer and device checks completed
- Text compared with the approved manuscript
- Specification and change log delivered
How we think
How we think about your EPUB validation
Structure first
In EPUB validation, EPUBCheck errors and warnings and usage notes are built into the file, not painted on top. For a EPUB validation, we treat structure as the foundation and appearance as the finish, because structure is what survives edits and platform changes.
Checked, not hoped
A file is not finished because it looks right on our screen in this EPUB validation order. It is finished when the validator, the preflight and real devices agree, and when we can show you the evidence with your EPUB validation. It is the principle behind most of what we do on EPUB validation, and the reason we prefer to explain our choices rather than hide them.
Your files stay yours
We deliver source files and a specification, and we never lock your EPUB validation work inside a proprietary format. If you hire someone else later, they can pick up where we stopped in this EPUB validation order. It is the principle behind most of what we do on EPUB validation, and the reason we prefer to explain our choices rather than hide them.
Client reviews
What authors say about our EPUB validation
Verified reviews from authors whose EPUB errors were fixed by our team.
A fixed-layout EPUB for a cookbook is genuinely complex. The recipe layouts, ingredient lists, and photography all needed to remain pixel-perfect. The result looks as good as the print version on every device.
I had a previous EPUB that displayed incorrectly on several devices. Book Formatting Experts rebuilt it from scratch. The new version renders beautifully across every reader app I tested.
Converting my nonfiction manuscript to EPUB while preserving the heading structure, footnotes, and internal links was no small task. Every element survived the conversion perfectly.
The reflowable EPUB looks perfect on every device I tested — Kindle, Apple Books, and Kobo. The clickable table of contents and chapter navigation work exactly as they should.
My business EPUB had tables and callout boxes that needed to be handled carefully. Everything was converted cleanly without losing any structural information. The file passed Amazon's validator on the first check.
Academic EPUB with complex equations and references. One formula needed manual correction in revisions but the overall quality was exactly right. The file validates without errors on all platforms.
The EPUB renders perfectly on my Kindle, Apple Books, and Kobo. The clickable table of contents works exactly as it should. Clean, standards-compliant, and ready to distribute everywhere.
Good eBook formatting work. The tables converted cleanly and the navigation works well. One heading level needed a style adjustment but it was corrected quickly. The file performs well on all platforms.
The interactive elements in my EPUB — internal links, chapter navigation, and resource appendix — all work perfectly. My readers have specifically mentioned how easy the ebook is to navigate.
My fantasy EPUB had complex nested structures with chapter epigraphs and world-building inserts. The EPUB handles every level cleanly and reads beautifully on Kindle and Apple Books.
My EPUB was rejected twice by Apple Books before I found Book Formatting Experts. They identified the metadata errors, rebuilt the file properly, and the new version passed immediately. Wish I had contacted them first.
Good formatting work overall. The chapter headers felt slightly generic at first but after one revision round they had exactly the right tone for my YA readership. File passed KDP without any issues.
The atmospheric chapter openings matched the tone of my books without being overdone. The specialist clearly understood what dark fantasy readers expect from a professionally formatted interior.
Business books need to feel authoritative while remaining readable. The interior design achieved both. The chapter structure is clear and every table reads cleanly. My corporate clients have all commented favourably.
Very good understanding of academic formatting requirements. One heading level needed adjustment in revisions but the overall standard was exactly right for a scholarly publication. My publisher was satisfied.
The interior design reflects the purpose of the book — accessible, warm, and inviting for daily reading. The scripture placement and reflection boxes are formatted consistently throughout. I am genuinely proud of how it looks.
Every genre convention was applied correctly. The chapter openers, the dedication page, and the acknowledgements all flowed naturally. Readers have complimented how comfortable the book feels to read.
Good quality work. The interior looked professional and the file passed KDP without issues. One revision round was needed for some heading spacing but it was fixed quickly and without any fuss.
FAQ
EPUB Validation: questions answered
These are the questions authors ask most about EPUB validation, including errors, tools and cost. If your question about the EPUB validation is missing, request a quote and a specialist will reply.
What is an EPUB validation tool?
It is software, such as EPUBCheck, that tests an EPUB against the standard. For EPUB validation, we check the result against the platform's own rules before you see it.
Is there an EPUB validator online?
Yes. Several online validators run EPUBCheck, and we also use it locally. We keep a record of what we changed so that you can review the work with your EPUB validation.
What are EPUB and HTML validation?
EPUB validation checks the package, and HTML validation checks the markup inside it. The calculator on this page shows the fixed price for each package before you commit on this EPUB validation project.
Do you offer EPUB validation services?
Yes. With your EPUB validation, if you are unsure, send the file and we will tell you what the job involves.
What are EPUBCheck errors explained?
Each error has a code and a location, and we explain what to change. Revision rounds are included, so the first delivery does not have to be perfect for the EPUB validation.
How do I validate an EPUB for KDP?
Run EPUBCheck, fix errors and test in Kindle Previewer. For EPUB validation, we check the result against the platform's own rules before you see it.
How do I validate an EPUB for Apple Books?
Run EPUBCheck, since Apple runs it on upload. We keep a record of what we changed so that you can review the work with your EPUB validation.
How do I validate an EPUB file?
Run EPUBCheck on the file and read the results. The calculator on this page shows the fixed price for each package before you commit on this EPUB validation project.
What is EPUB accessibility validation?
It is testing whether the EPUB meets accessibility standards, using tools such as Ace. With your EPUB validation, if you are unsure, send the file and we will tell you what the job involves.
Can you fix EPUB validation errors?
Yes. Revision rounds are included, so the first delivery does not have to be perfect for the EPUB validation.
Do you give an EPUBCheck pass guarantee?
Where repairs are included, we repair until the file passes EPUBCheck with zero errors. For EPUB validation, we check the result against the platform's own rules before you see it.
How much does EPUB validation cost?
The calculator on this page shows a fixed price for each package with your EPUB validation. We keep a record of what we changed so that you can review the work with your EPUB validation.
Is there an EPUB validation tool?
Yes, EPUBCheck is the standard. We run it and fix what it finds. The calculator on this page shows the fixed price for each package before you commit on this EPUB validation project.
Can I validate online?
Online validators exist. We use them and EPUBCheck. With your EPUB validation, if you are unsure, send the file and we will tell you what the job involves.
What does EPUB and HTML validation mean?
The markup inside an EPUB must also be valid HTML. We check both. Revision rounds are included, so the first delivery does not have to be perfect for the EPUB validation.
How do I validate epub for KDP in practice?
To validate epub for KDP, run EPUBCheck, fix every error and then upload to KDP's previewer to confirm that it converts cleanly.
How much does EPUB validation cost?
The epub validation cost starts at $169 for a short book and rises to $689 for the longest length priced online. Epub validation services of this kind are priced by word count and images, and the calculator gives the exact total.
Ready when you are
Ready to start your EPUB validation?
A validated file is the difference between a book that publishes on the first try and one that stays in a queue. See what yours would cost in a minute, or send a larger project and we will quote it.
- Fixed price shown before you pay
- Revision rounds included
- One named specialist, brief to upload