ChangeThisFile vs CoolUtils Online: Which Converter Wins?

CoolUtils has a longer history as a desktop software vendor (Total PDF Converter, Total Image Converter, etc.) with an online tool as a companion product. The online converter is functional but narrower than the desktop products, and it requires a paid subscription for anything beyond basic use.

ChangeThisFile is web-first: 690 routes, client-side processing for common formats, and a developer API that starts free. This comparison focuses on the online tools since that's what most users are evaluating.

Quick verdict

For free web conversion: ChangeThisFile — unlimited, no signup, no ads, broader coverage.

For privacy-sensitive files: ChangeThisFile — images, data files, and fonts convert in your browser without uploading.

For developer API access: ChangeThisFile. CoolUtils online has no free REST API.

For installed desktop software (Windows): CoolUtils. Their desktop apps (Total PDF Converter, etc.) are well-regarded for batch conversions on Windows. ChangeThisFile has no desktop app.

Pricing comparison

CoolUtils's online tool has a free conversion limit before requiring a subscription. Their desktop software is a separate one-time purchase. ChangeThisFile's web converter is always free and unlimited; paid tiers are for API volume only.

Feature comparison

Privacy and data handling

CoolUtils online processes files server-side — files are uploaded to their servers for conversion. Their desktop apps (notably) are different: local processing with no upload at all, which is a strong privacy advantage for desktop users.

ChangeThisFile's client-side routes match the desktop privacy model for web use. Images (JPG, PNG, WebP, GIF, BMP, ICO, AVIF, SVG, TIFF, HEIC, PSD), data files (CSV, JSON, YAML, TOML, XML, TSV), spreadsheets (XLSX), DOCX→HTML, HTML↔Markdown, image-to-PDF, and fonts: nothing is uploaded — the conversion runs in your browser.

If privacy is the primary concern and you're on Windows, CoolUtils desktop apps are worth considering. For web-based conversion with equivalent privacy, ChangeThisFile's client-side routes are the answer.

API and developer experience

CoolUtils online has no REST API for external integration. Their desktop software has scripting interfaces on some products, but nothing comparable to a web API.

ChangeThisFile's API is curl-ready with no SDK or library installation:

curl -X POST https://changethisfile.com/v1/convert \
  -H "Authorization: Bearer ctf_sk_your_key" \
  -F "file=@image.heic" \
  -F "target=jpg" \
  --output image.jpg

Source format is auto-detected from the filename. Get a free key at changethisfile.com/v1/keys/free — 1,000 calls/month, no credit card, no trial period. Paid plans scale up to $1,999/mo for high-volume API use.

Format coverage

CoolUtils online focuses on documents (PDF, DOCX, ODT, HTML), images (JPG, PNG, TIFF, BMP), and some audio formats. The desktop apps cover more — Total Video Converter handles video; Total Audio Converter handles audio. Online, the coverage is more limited.

ChangeThisFile's 690 online routes cover all of that plus: video (MP4, MKV, WebM, AVI, MOV, FLV, WMV), audio (MP3, WAV, FLAC, AAC, M4A, OGG), ebooks (EPUB, MOBI, AZW3, FB2, CBR/CBZ), archives (ZIP, RAR, 7Z, TAR and variants), and fonts (TTF, OTF, WOFF, WOFF2).

When to choose which

CoolUtils has a legitimate niche in Windows desktop batch conversion — if you're regularly processing hundreds of files locally, their desktop apps are worth evaluating. For web-based conversion, developer API access, or broader format coverage without a subscription, ChangeThisFile is the better fit. Free API tier, no card required.