What it does
Every percentage question
Percent of a number, percentage change, discounts, sales tax and VAT, part of a whole, the price before the rise — eight calculators plus ready-made everyday scenarios.
It shows the work
Not just the result: the formula and the steps that led to it, written out in plain language. Good for checking, better for learning.
Search like you think
Type “20% off”, “tip” or “rent hike” and land in the right calculator. No menu spelunking.
Your favorites first
Star the calculators you use and filter the home screen down to them. Favorites are stored in your browser, not on a server.
Installs like an app
Add it to your home screen on iPhone or Android — or install it on your laptop. Own icon, full screen, no app store in between.
Works offline
Turn on Offline mode at the bottom of the app — or install this site as an app — and the calculators keep working with no connection at all, in a basement shop or on a plane.
Three everyday scenes
The sale rack, decoded
Sneakers at $79, the tag says 20% off. Two fields, one glance: $63.20. The discount calculator asks only for the price and the percent — and shows how much stays in your pocket.
The rent letter, translated
Rent going from $1,200 to $1,290 — is that a lot? The percentage-change calculator says 7.5%, and the Equation panel right above it writes out the formula with your own numbers in it, so you can see exactly where that figure came from.
The same app on every screen
Phone in the shop, laptop at your desk — one address, the same calculators, no install required. And if you want it one tap away, it pins to your home screen like any other app.
Private by design
Your numbers stay in your browser
Every calculation runs on your device, in the page you are looking at. The amounts you type are never sent to a server.
No account, nothing to leak
There is no sign-up, no profile and no cloud copy of your data. Favorites live in your browser’s own storage.
Consent-first analytics
The app asks before measuring anything. Anonymous usage analytics runs only after you tap “Accept” — “Reject all” sits right on the first banner, and Global Privacy Control is honored. This landing page sets no cookies at all.
Free. Actually free.
No sign-up, no paywall, no premium tier — every calculator is open to everyone. Just Percent is built by the same one-person studio that makes Bilargo’s paid Mac and iPhone apps, and that is what keeps the lights on.
Open Just Percent — it’s freeQuestions, answered
Is it really free?
Yes. Every calculator works without payment, sign-up or trial limits.
Does it work offline?
Yes, once you ask for it. Tick “Offline mode” at the bottom of the app, or install this site as an app on your phone or laptop, and the calculators keep working without a connection — handy in a shop with no signal. It stays off until then because keeping a copy on your device needs your say-so.
How do I install it on my phone?
Open justpercent.com, then add it to your home screen (Safari: Share → Add to Home Screen; Chrome: Install app). The full walkthrough is in our install guide.
Is my data private?
Calculations never leave your device. Usage analytics runs only if you explicitly accept it on the consent banner — rejecting is one click and everything still works.
Are there ads?
No ads today. If ads ever help keep the free tools free, they will be clearly labeled and switched on only under the same consent rules as everything else.
Try it on the next price tag
No download needed — open it, type two numbers, and keep it if it earns its place on your home screen.
Open Just Percent — it’s free