Best Free PDF to EPUB Converters Compared: toolkit.bot, Calibre, Zamzar, iLovePDF, CloudConvert, Smallpdf
We tested four tools on the same set of PDFs: a scanned book, a two-column academic paper, a report with tables, and a standard single-column document. Below the test results you'll find a single comparison table that also covers CloudConvert, Smallpdf and Online-Convert, so every free converter people ask about is on one page.
Summary: toolkit.bot handles complex PDFs (scanned, multi-column, tables) best. Calibre is the best offline option for simple files. Zamzar, iLovePDF, CloudConvert and Smallpdf are general-purpose converters: fine for clean single-column text, inconsistent on anything structured, and none of them runs OCR.
The tools tested
- toolkit.bot — browser-based, no install. Free tier: 5 conversions/month; Pro ($9/month) is unlimited.
- Calibre — desktop app (100MB+), free and unlimited. Windows/Mac/Linux.
- Zamzar — browser-based general file converter. Free tier limited; paid plans add API access and larger files.
- iLovePDF — browser-based PDF toolkit. Free tier limited; Premium removes the caps.
Test 1: Scanned PDF (image-only pages)
A 120-page scanned book, no embedded text layer.
| Tool | Result |
|---|---|
| toolkit.bot | ✓ OCR ran automatically. Searchable EPUB with ~98% character accuracy on clean scan. |
| Calibre | ✗ No OCR. Output EPUB contained blank pages — no text extracted. |
| Zamzar | ✗ Output contained image placeholders but no text content. |
| iLovePDF | ✗ Produced an EPUB file but with no readable text — images only. |
Winner: toolkit.bot (only tool with automatic OCR). OCR conversion guide →
Test 2: Two-column academic paper (arXiv-style)
A 20-page two-column research paper from arXiv, with figures and equations.
| Tool | Result |
|---|---|
| toolkit.bot | ✓ Two columns correctly separated. Reading order preserved throughout. |
| Calibre | ✗ Merged both columns into a single stream — alternating sentences from column 1 and column 2. |
| Zamzar | ✗ Similar merging problem — garbled reading order. |
| iLovePDF | ⚠ Column separation attempted but with errors in the middle sections. |
Winner: toolkit.bot. arXiv conversion guide →
Test 3: Report with tables
A 40-page business report with 8 data tables and mixed text/chart sections.
| Tool | Result |
|---|---|
| toolkit.bot | ✓ Tables converted to HTML <table> elements. Structure preserved. |
| Calibre | ⚠ Tables extracted as plain text rows — readable but no visual structure. |
| Zamzar | ⚠ Mixed results — simple tables OK, complex ones garbled. |
| iLovePDF | ⚠ Similar to Zamzar — inconsistent table handling. |
Winner: toolkit.bot.
Test 4: Simple single-column book
A 250-page single-column novel in PDF, clean digital scan.
| Tool | Result |
|---|---|
| toolkit.bot | ✓ Clean reflowable output. Headings detected and structured. |
| Calibre | ✓ Also good output. Slight differences in heading detection. |
| Zamzar | ✓ Adequate for simple files. Paragraph spacing slightly off. |
| iLovePDF | ✓ Adequate. Output quality comparable to Zamzar. |
All tools perform adequately on simple files. Calibre is the best offline option here since it's free and unlimited.
Every free converter compared
One row per tool. Everything in this table comes from our own tests above or from the tools' published limits; where we have not run a test, the cell says so.
| Tool | Runs where | Free tier | Scanned PDF (OCR) | Multi-column layout | Headings / TOC | Tables | Best for |
|---|---|---|---|---|---|---|---|
| toolkit.bot | Browser | 5/month; email sign-in for the download | Built in, automatic | Detected; reading order preserved | Headings and TOC generated; EPUB3 with accessibility metadata | HTML tables | Scanned, two-column and table-heavy PDFs; accessible EPUB3 |
| Calibre | Desktop app (Windows, Mac, Linux; ~100 MB) | Unlimited, no account | None (plugin needed) | Columns merge unless set manually | Basic heading detection | Plain text rows | Simple single-column books in bulk, offline; any-to-any ebook formats (EPUB, MOBI, AZW3) |
| Zamzar | Browser (email delivery) | Limited; 50 MB; email address required | None | Columns merge | Basic; EPUB 2 output | Plain text | Simple PDFs when you already convert other formats there |
| iLovePDF | Browser | Daily cap; no email required | None (separate OCR tool) | Attempted, with errors | Rarely preserved; no TOC | Structure lost | Simple single-column PDFs; compress or split a PDF before converting elsewhere |
| CloudConvert | Browser; REST API with webhooks (paid) | 25 conversion minutes/day | None | Columns merge | Flat text; no TOC | Inconsistent | Multi-format pipelines (200+ formats) and API automation |
| Smallpdf | Browser | 2 operations/hour; no email required | None | Columns merge | Flat text; no TOC | Not tested | Clean single-column files if you already pay for Smallpdf Pro |
| Online-Convert.com | Browser | 10/day with size limits | None | Not tested | Not tested | Not tested | Obscure or legacy ebook format pairs |
Free and paid tiers of toolkit.bot run the same conversion pipeline — OCR, column detection, table extraction — so paying changes the monthly quota and file size limit, not the output quality.
Beyond PDF: which free tool for which ebook task
| Task | Best free tool |
|---|---|
| PDF → EPUB (any PDF, including scanned) | toolkit.bot (OCR built in) |
| EPUB → MOBI / AZW3 | Calibre |
| EPUB → PDF | Calibre or CloudConvert |
| Word / DOCX → EPUB | Calibre, or Word → PDF → toolkit.bot |
| Batch convert 100+ files | Calibre command line, or the toolkit.bot API |
Which tool should you use?
Use toolkit.bot if: your PDF is scanned, has two-column layout (academic papers), or contains data tables. Also the best choice if you need accessibility-compliant EPUB output.
Use Calibre if: you're converting simple single-column books in bulk, want unlimited conversions with no account, and prefer local processing. Calibre comparison guide →
Use Zamzar, iLovePDF, CloudConvert or Smallpdf if: you occasionally convert simple single-column PDFs and already use one of these services for other file tasks. CloudConvert is also the one to pick when you need a single API across many formats.
Try toolkit.bot on your PDF — scanned, multi-column, or simple.
Convert PDF to EPUB Free →