About FileConverters

FileConverters exists because the most common file chore on the internet — "I have this image in the wrong format" — is usually solved by uploading personal files to a stranger's server and hoping. We think that is backwards. Every tool on this site runs as JavaScript inside your own browser tab: your images are decoded, converted, and verified on your device, and the site has no upload endpoint to send them to even if it wanted one. FileConverters is published by Sumvia, the team behind the Sumvia.net calculator network.

The tools

The site ships sixteen focused tools rather than one vague "convert anything" box.Convert Images holds twelve directional converters — the six between the web's three working formats, WebP to PNG,WebP to JPG, PNG to JPG,JPG to PNG, PNG to WebP, andJPG to WebP; HEIC to JPG andHEIC to PNG for iPhone photos; and four AVIF lanes,JPG to AVIF and PNG to AVIF for modern compression plus AVIF to JPG andAVIF to PNG for the way back — each with its own page because each direction has its own honest trade-offs (JPG drops transparency; PNG grows; WebP needs a modern destination; HEIC needs a decoder browsers don't have, so those two pages load one; AVIF encoding costs real seconds of CPU, so those pages say so).Optimize holds the Image Compressor (quality slider or compress-to-target-KB), Compress JPEG (the MozJPEG lane — JPEG-only but measurably smaller at the same quality), and the Image Resizer(fit, exact, percent).Documents holds Image to PDF, which assembles multiple images into one PDF using this site's own small, tested PDF writer — no bundled library.

Who it serves

The person who right-clicked "Save image" and got a .webp their software rejects. The applicant whose upload form demands "JPG under 200 KB". The developer chasing a page-speed score. The freelancer turning a folder of receipts into one PDF. None of these jobs should require an account, an install, or surrendering the files to a server — so here, none of them do.

Honesty as a feature

File tools have a marketing problem: "up to 90% smaller!" banners, fake progress bars over uploads, "enhanced quality" claims physics does not permit. FileConverters takes the opposite position. Every result row shows the file's real before/after byte counts. Conversions that discard information say so before you run them — JPG output states that transparency will be flattened onto a color you choose; WebP pages state that animation survives only as a first frame. When a target size is unreachable or a "compressed" file comes out bigger than the original, the tool tells you and suggests keeping the original. And every output is verified — re-decoded, dimension-checked, magic-byte-sniffed — before a download button appears.

Tested logic, verifiable claims

The decision-making inside every tool — format detection from file bytes, conversion planning, resize arithmetic, the compression search, the PDF writer — is implemented as small, pure functions with an automated test suite that pins their behavior, including the failure cases. Worked examples in page copy are computed at build time by that same code, so documentation cannot drift from behavior. The privacy claim is architectural: a security policy that blocks network requests to any other origin, verifiable in your browser's DevTools. Themethodology page spells out both.

Browser-native, no accounts

Nothing you drop on a tool is transmitted, logged, or stored by us; closing the tab destroys the work. There is no registration and the tools keep working on a flaky connection once a page has loaded. This is a deliberate design constraint of every Sumvia site.

Limits, stated plainly

These tools cover PNG, JPG, WebP, GIF, BMP, and AVIF inputs — the formats browsers decode natively — plus HEIC, decoded by a self-hosted copy of the open-sourcelibheif library running in your browser. They produce PNG, JPG, WebP, AVIF, and PDF — never HEIC, which would require an HEVC encoder burdened by patent pools that browsers and this site do not carry (AVIF's AV1 codec is royalty-free, which is exactly why it IS produced here). Beyond the browser's own encoders, two self-hosted open-source encoders do the heavier lifting: MozJPEG forCompress JPEG and libavif+aom for the AVIF pages — themethodology page has the full attributions. The tools do not read camera RAW formats, do not batch-process thousands of files, and do not edit pixels (no cropping beyond resize-fill, no retouching). Where a browser cannot do something honestly — genuinely compressing a PNG as a PNG, for instance — the tool offers the honest alternative and names it, rather than pretending.

Get in touch

Found a file that converts wrongly, or want another tool? See thecontact page — reports of conversion problems are especially welcome and treated seriously: confirmed issues get fixed in the engine and locked in with a new test.