Free online tools that work without taking your files
Convert a photo, shrink a video, build an invoice. It All Stays Here runs everything inside your own browser — so nothing is uploaded, nothing is stored, and nothing asks you to sign up.
PDF, image, video, audio and calculator tools
47 of them, and more each week. Each one does a single job properly, on your device.
Merge PDF
Combine PDFs into one file. Drag to reorder before you save.
Compress PDF
Get a heavy PDF under the upload limit that keeps rejecting it.
Sign PDF
Draw your signature, put it where it goes, download. The contract never leaves your computer.
Split PDF
Pull out the pages you need, or break a document into separate files.
JPG to PDF
Turn photos into one tidy PDF. Reorder them, pick the page size, done.
PDF to JPG
Every page as an image, at the resolution you choose. Nothing is uploaded.
Rotate PDF
Fix pages that scanned in sideways or upside down, one page or all of them.
Delete PDF Pages
Remove the blank scans, the cover sheet, or anything you would rather not send.
Add Page Numbers
Number a PDF properly — position, starting number, and which pages to skip.
Watermark PDF
Stamp DRAFT, CONFIDENTIAL or your own text across every page.
Compress Image
Get photos under an upload limit, by quality or by a size you name. Batch supported.
Resize Image
Exact dimensions, with presets for every social format. Crop to fill or pad to fit.
Crop Image
Drag a frame over the picture, freehand or locked to a shape. Nothing is uploaded.
Image Converter
PNG, JPG, WebP and AVIF in any direction, with transparency handled properly.
Paste Image
Press Ctrl+V and save a copied picture as a file. Windows has no way to do this on its own.
Passport Photo
Official sizes for 20 countries, with a print sheet you can take to any shop.
Compress Video
Shrink a clip until it fits WhatsApp, email or Discord. Pick the destination, not a bitrate.
Video to MP3
Take the sound out of a video and keep just that. MP3, or the original track untouched.
Cut Video
Keep the part you want. A fast cut copies the video untouched, with no re-encoding.
Video to GIF
Turn a few seconds into a GIF. The colours come from your own frames, so it looks right.
Mute Video
Take the sound off a video without touching the picture. Instant and lossless.
Auto Subtitles
Animated captions like TikTok and Shorts, generated automatically and editable by hand.
Audio Converter
MP3, WAV, M4A, OGG or FLAC — convert between them without uploading a thing.
Audio Cutter
Trim a song or recording to the part you actually want. Drag the handles, save it.
Merge Audio
Join several tracks into one file, in the order you choose.
Voice Recorder
Record straight from your microphone and save it. Nothing is sent anywhere.
Percentage Calculator
The four percentage sums, each with the arithmetic written out underneath.
Discount Calculator
Sale price, percent off, or the original — including what stacked discounts really save.
Age Calculator
Exact years, months and days, the weekday you were born, and the next birthday.
Tip Calculator
The tip, the total, and a split that divides evenly when the bill will not.
Decoy Pricing Calculator
Price a third option that nudges customers toward the one you actually want sold, with the reasoning shown as arithmetic.
Time Zone Converter
What time it is somewhere else on the date you actually mean, with the daylight saving shown rather than assumed.
BMI Calculator
Metric or imperial, with the healthy weight range for your height and Asian cut-offs.
One Rep Max
The most you could lift once, from a set you did — with the seven formulas and how far apart they are.
Pace Calculator
Pace, finish time or distance from any two of them, with every split and the same effort at other race distances.
Working Days
Business days between two dates, with your own weekend, your own holidays and no argument about the last day.
Grade Calculator
Your weighted average, and what you need on the final to hit the mark you want.
Loan Calculator
Monthly payment, total interest, and the full amortisation schedule as a PDF.
Compound Interest
Watch savings grow, and see the year the interest starts outpacing what you put in.
Credit Card Payoff
How long the minimum payment really takes, and what paying more actually saves.
QR Code Generator
Links, Wi-Fi, email and more. The code points straight at your data, with no redirect.
Barcode Generator
EAN-13, UPC-A, EAN-8 and Code 128, with the check digit worked out and a warning when yours is wrong.
Password Generator
Strong passwords and passphrases, made on your machine and never transmitted anywhere.
Password Checker
See how a guesser reads your password. It finds the dictionary word you thought you hid.
Invoice Generator
Fill in the details, download the PDF. No sign-up wall between you and the invoice.
Remove Background
Cut the subject out of a photo. The model runs on your device, so nothing is uploaded.
Image to Text
Pull the words out of a photo or screenshot. Six languages, and nothing is uploaded.
Guides
Longer answers to the question that comes before the tool: what the format actually is, why the form keeps refusing the file, and what the app did to your photo on the way out.
What is a HEIC file, and why will your PC not open it?
Half the size of a JPG, and a patent licence is why Windows refuses it.
How to get a PDF under an upload limit
Most PDFs cannot be compressed at all. Ten seconds tells you which kind you have.
Why WhatsApp ruins your photos, and how to send one properly
It re-compresses every picture you send. There is one way around it, and it is not the quality setting.
JPG or PNG: which should you use?
Photographs, JPG. Hard edges or transparency, PNG. The reason is worth two minutes.
How to get a photo under a KB limit
The quality slider is the wrong first move. Pixels are the lever that works.
Are QR codes safe? What is actually inside one
Nothing inside one can run. The risks are the destination, the sticker over the original, and who owns the code.
Why video files are so big, and what actually shrinks them
Bitrate times length is the file size. Everything else follows from that.
MP3, WAV or M4A: which audio format, and at what bitrate?
128 kbps is about a megabyte a minute. Everything else follows from that.
Percentages, and the four sums people actually get wrong
20% off then 10% off is not 30% off, and adding 20% then taking it back leaves you short.
How to take a passport photo at home that is not rejected
The rule is the height of your head, not the size of the photo — and the shadow behind you is geometry.
How to make a ringtone, and why the cutting is the easy part
Android takes an MP3 straight. An iPhone wants an M4R, which is an M4A with a different extension.
Compound interest, in both directions
Savings growing and a card balance running away are the same sum. Only the side you are standing on differs.
What actually happens when a password leaks
Why one company’s bad week becomes your problem at forty other sites — and the single habit that breaks the chain.
What you can change in a PDF without Acrobat
Moving pages and stamping them costs nothing. Changing the words is the one genuinely hard edit, and this is why.
Are electronic signatures legally binding?
Valid nearly everywhere — but a drawn signature proves the mark is there, not who put it there. What that changes, and when it is not enough.
Why background removal cuts off hair
Hair, glass and plants come out ragged for a reason that is not fixable by trying another site. What causes it, and what to photograph instead.
Why OCR gets text wrong
Why the mistakes land in invoice numbers rather than in sentences, what actually ruins a scan, and how to photograph a page properly.
What the numbers on a barcode mean
Three fields and a checksum. Why “690 means made in China” is wrong, and how the last digit is worked out from the others.
Why date calculators disagree with each other
One month after 31 January is 28 February, 2 March or 3 March depending on the rule. Why the calendar refuses to be arithmetic.
What fitness numbers actually tell you
Why the level a fitness formula gives you is usually wrong, why the change usually is not, and which of the two is worth watching.
What has to be on an invoice
The blocks nearly every country expects, the two that people get wrong, and why “net 30” gets paid later than a date.
Subtitles: a separate file, or burned into the video?
A file the player draws, or pixels in the picture. What each costs, and why automatic captions get names wrong and sentences right.
Why your final grade is not the average of your grades
The same four marks give 82.5 averaged and 74.0 weighted. How weighting works, and what you really need on the final.
Does decoy pricing actually work?
A real 1982 effect, a famous 84%-vs-32% demonstration, and a 2014 attempt to reproduce it on real products that worked about once in eight tries.
How to save a picture that is only on the clipboard
Why Ctrl+V does nothing in a folder after you copy a picture, what your computer can already save on its own, and the shortest way round it.
Why "on device" matters
Almost every free file tool online works by taking your file first. These don't, and that changes several things at once.
Your file stays yours
Bank statements, passport scans, client contracts, family photos. None of it is transmitted, because there is no server doing the work.
No upload wait
Work starts the instant you drop the file in. On a big file that alone can save several minutes.
No account, ever
Other tools gate the download because each file costs them server time. Ours cost nothing to run, so there is nothing to gate.
Works offline
Load a tool page, disconnect from the internet, and it still works. That is the simplest proof that nothing is being sent.
How it's possible to do this in a browser
For most of the web's history, anything demanding — converting a photo format, re-encoding a video, building a PDF — had to happen on a server. Browsers simply were not fast enough, and the code to do it did not exist in a form they could run.
That changed with WebAssembly, a way of running compiled programs at close to native speed inside a web page. The same decoders and encoders that power desktop software can now be compiled to run in a browser tab. A video encoder, an image decoder, a PDF writer — all of it fits in a page and runs on your own processor.
The practical effect is that the economics flip. A conventional online converter pays for bandwidth and processing on every single file, which is why it caps your file size, limits your daily conversions and asks you to create an account it can eventually charge. When the work happens on your machine instead, those costs are zero, and so are the reasons to restrict you.
There are genuine trade-offs, and it would be dishonest to skip them. Browser tabs have a memory ceiling, so very large files can fail. Encoding cannot use your graphics card, so it runs slower than a desktop program. Every tool here states its limits up front rather than letting you discover them halfway through.
For everything that fits inside those limits — which is the overwhelming majority of everyday tasks — doing the work locally is faster, more private, and free of the small indignities that come with the alternative.