Honest tooling
What the tools can — and can't — do.
FormatOS is built to be useful and honest. These are the real limits of what the tools can promise — explained plainly, without burying anything in fine print.
Last reviewed: June 29, 2026
Before anything else
Keep your original. Always.
The single most important thing you can do before using any file tool — ours or anyone else's — is keep a copy of the original file untouched. Everything else can be recovered from there.
The honest list
Six things worth knowing.
Each limitation below includes what happens, why it happens, and what to do about it.
Conversion can change how a file looks
Format changes aren't always lossless — and that's normal.
What happens
When you convert a file from one format to another, the output may look or behave slightly differently. Spacing, fonts, colours, table layouts, embedded images, and page structure can shift depending on how different formats handle those elements.
Why it happens
Every file format has its own rules for what it can store and how. A PDF and a DOCX don't speak the same language — when you translate between them, some things get approximated.
What to do
Always review converted files before using them for anything important. For legal, financial, academic, or official documents, have a human check the output.
Compression trades size for quality
Smaller files sometimes mean lower quality — we won't pretend otherwise.
What happens
Aggressive compression reduces file size by discarding or approximating data. Image compression can soften edges and introduce artefacts. Targeting a very small file size may visibly degrade the output.
Why it happens
There's no magic — you're trading quality for size. Lossless compression preserves everything but delivers smaller savings. Lossy compression can go further but changes the file.
What to do
Start with a moderate compression level. Preview the output before downloading. Keep your original if quality matters.
Large files can hit browser limits
Your browser and device have a ceiling — and that ceiling varies.
What happens
Very large files can exhaust browser memory, slow processing to a crawl, or time out entirely. A file that works fine on one device may hit limits on another with less RAM or a slower connection.
Why it happens
Every current tool runs entirely in your browser, on your device's available memory. There's no server absorbing the load for these operations — it's your tab doing the work, and your files are not uploaded to FormatOS servers.
What to do
If a large file fails, try a smaller version first. For large PDFs or high-resolution image batches, expect longer processing times or failures on lower-spec devices.
Metadata cleanup isn't perfect privacy
We reduce common hidden fields — we don't guarantee a clean slate.
What happens
Metadata removal strips commonly known hidden fields: GPS location, camera model, author name, document revision history, and similar. But metadata in complex formats can be deeply embedded, partially regenerated, or stored in non-standard fields.
Why it happens
File formats like PDF and DOCX have dozens of places metadata can live. Removing the obvious ones doesn't guarantee all traces are gone — and some applications re-add metadata on save.
What to do
For genuinely sensitive files, use a dedicated privacy tool in addition to FormatOS. Don't rely solely on any single web tool to clean files that carry real risk.
Not every operation is part of the current toolset
If a tool isn't visible, it's not offered right now — not hidden behind a paywall.
What happens
Every current public tool — PDF merge, split and compress; image resize, compress and convert; CSV/JSON/XML/YAML cleanup; text cleaning; ZIP preparation; EPUB inspection and conversion; scan cleanup; and bank statement PDF to XLSX — runs entirely in your browser, and your files are not uploaded to FormatOS servers. Operations outside this set simply aren't part of the toolset today.
Why it happens
We only show tools that are genuinely ready to work on-device. If a future tool ever needs temporary server-side processing, its own tool page will clearly disclose that before you upload anything.
What to do
If an action you expected to see isn't there, it likely isn't part of the current toolset. Use one of the supported tools above, or check the Supported Formats page for what's available.
We can't guarantee third-party acceptance
FormatOS prepares your file — what happens next depends on who's receiving it.
What happens
A file that FormatOS converts, compresses, or prepares may still be rejected by a government portal, bank form, university submission system, or employer. Their requirements are set by them, not by us.
Why it happens
Each platform has its own rules: specific resolution requirements, exact colour profiles, DPI thresholds, or proprietary format variants. We can get your file close — we can't guarantee it clears every gate.
What to do
Check the receiving platform's exact requirements before converting. If a submission fails, compare the platform's specs against your output and adjust accordingly.
If something goes wrong
What to try when a tool doesn't work.
Try a smaller file
If the file is large, a reduced version often succeeds when the full one doesn't.
Try a simpler format
Some formats have edge cases. Try converting to a common intermediate format first.
Refresh and retry
Browser memory issues clear on reload. A second attempt sometimes succeeds.
Use a different browser
Different browsers have different memory limits and format support.
Check the file isn't corrupted
Try opening the file in its native app first. If it fails there, the file itself may be the problem.
Report it
If something consistently fails and shouldn't, let us know via the Contact page.
Read more
Related pages.
Now that you know the limits —
Go ahead and upload your file.
Most files work great. The tools are honest when something won't. Keep your original and you're always safe.