Online-Convert.com has been around for years and built a reputation for device-specific presets — you can convert a video "for Kindle" or a document "for iPhone" with optimized settings baked in. That's a genuine convenience for non-technical users who don't know what codec settings they need.
ChangeThisFile focuses on a different set of strengths: a clean, ad-free interface, client-side processing for privacy-sensitive formats, and a free API tier that works without a credit card. What it does not offer is a bigger free allowance — the free web tool is one conversion per day, which is a tighter cap than Online-Convert's ad-supported free tier. This comparison covers both tools honestly, which means saying that out loud before anything else.
Quick verdict
For everyday conversions without ads: ChangeThisFile. Clean interface, no pop-overs, no account — but budget for the cap: one free conversion per day, then $2.99 for a 24-hour unlimited day pass.
For more free conversions in a day: Online-Convert.com. Its free tier is ad-supported and metered, but it allows more than a single file per day.
For device-optimized presets (Kindle, iPhone, etc.): Online-Convert.com has a specific advantage here with built-in presets tailored to popular devices.
For privacy: ChangeThisFile. Client-side routes for images, data files, and fonts never upload to any server.
For free API access: ChangeThisFile. Free tier with 25 conversions/month and no card required.
Pricing comparison
| Plan | ChangeThisFile | Online-Convert.com |
|---|---|---|
| Free browser tool | 1 conversion/day — no ads, no signup | Limited files/day, ad-supported — more than 1/day |
| Unlock the browser tool | $2.99 day pass (24h unlimited) or $9.99/mo Pro | Subscription removes ads and raises the daily limit |
| Free web file size | 25 MB for server-side routes | Capped on free, raised by subscription |
| Free API | 25/mo, no daily cap, no card | No free API tier |
| Entry paid API | $29/mo — 1,500 conversions | Subscription plans available (check their site for current pricing) |
| API access | All tiers including free | Paid plans only |
Both business models meter the free web tier; they just meter it differently. Online-Convert.com sells a subscription that removes ads and raises a daily file count that already allows several conversions a day. ChangeThisFile shows no ads to anyone and asks nothing at signup, but its free allowance is a single conversion per day — server-side and browser-side routes both count — and the unlock is a $2.99 pass for 24 hours rather than a monthly plan. On free daily volume, Online-Convert.com is the more generous of the two. ChangeThisFile's argument is the absence of ads and the fact that many conversions never leave your machine, not the size of the free tier.
Feature comparison
| Feature | ChangeThisFile | Online-Convert.com |
|---|---|---|
| Ads | None | Yes on free tier |
| Free daily conversion limit (web) | 1/day — client- and server-side routes both count | Yes on free tier, and higher than 1/day |
| Device presets (Kindle, iPhone, etc.) | No | Yes — notable strength |
| Client-side conversions | Yes — 193 routes | No |
| Free API tier | Yes — 25/mo, no card | No |
| Per-format advanced settings | Basic | More detailed options |
| Cloud URL import | No | Yes (convert from URL) |
| Batch conversion | No | Yes (paid plans) |
| No signup required | Yes (browser tool) | Limited without account |
Format coverage
Online-Convert.com supports a wide range of formats across image, video, audio, document, ebook, and hash/checksum tools. Their device-preset system covers a long list of popular devices — a useful shortcut for users who don't know which settings to use for a specific target device.
ChangeThisFile covers roughly 1,000 routes across 82 formats. Client-side image routes (JPG, PNG, WebP, HEIC, AVIF, GIF, BMP, ICO, SVG) use the browser's Canvas API. Server-side routes use FFmpeg for video/audio, LibreOffice for documents, Calibre for ebooks, and 7-Zip for archives.
For mainstream formats, both tools have strong coverage. Online-Convert's device preset library is a differentiated advantage for specific workflows (ebook reader preparation, mobile video, etc.).
Privacy and data handling
Online-Convert.com is server-side only. All files are uploaded for processing. Their privacy policy covers deletion timelines.
ChangeThisFile converts 193 routes in the browser without any upload. For all major image formats, common data formats (CSV, JSON, YAML, XML, TOML, TSV), markup conversions (HTML↔Markdown, DOCX→HTML), PSD, HEIC, and font formats, your file never leaves your device.
For server-side routes (video, audio, complex documents, archives), ChangeThisFile uploads over encrypted HTTPS and auto-deletes files after conversion — behavior similar to Online-Convert.com for those formats.
API and developer experience
Online-Convert.com provides a developer API on paid plans. Their API supports conversion with format-specific settings and URL-based file import (convert a file from a URL without uploading).
ChangeThisFile's API is simpler and free to start:
curl -X POST https://changethisfile.com/v1/convert \
-H "Authorization: Bearer ctf_sk_your_key" \
-F "file=@video.avi" \
-F "source=avi" \
-F "target=mp4" \
--output video.mp4
Get a key at changethisfile.com/v1/keys/free — one HTTP request, no account, no card. The response is the converted file directly.
When to choose which
| Use case | Recommended |
|---|---|
| Clean, ad-free conversions | ChangeThisFile |
| Privacy-sensitive files | ChangeThisFile (client-side routes) |
| Free API for integrations | ChangeThisFile |
| The most free conversions in a day | Online-Convert.com — ChangeThisFile's free web tool stops at 1/day |
| One day of unlimited conversions, no subscription | ChangeThisFile ($2.99 day pass) |
| Device-optimized presets (Kindle, iPhone) | Online-Convert.com |
| Convert from URL (no local file) | Online-Convert.com |
| Advanced per-format settings via web UI | Online-Convert.com |
Online-Convert.com's device presets are worth knowing about if you regularly prepare files for specific devices, and its free tier lets you convert more files in a day than ours does. Where ChangeThisFile is the better answer is narrower and more specific: no ads at any tier, no account, files that stay in your browser on 193 routes, and a free API key that works without a credit card. If you need several free conversions today, go to Online-Convert. If you need one clean conversion now, or a $2.99 day of unlimited ones, or an API you can call in two minutes, come here. Free API key →