Calculator & unit converter

Online calculator, unit converter and money tools

One page, three jobs. You get a full scientific calculator, a universal unit converter that spans 11 categories, and a shortcut to a row of financial calculators for the kind of decisions that actually cost money. No download, no account, no waiting. Type a formula, hit Enter, move on.

The scientific side isn't a four-button toy. It reads whole expressions, so you can write (2+3)*4 or 2^10 and let it sort out the order of operations for you. Parentheses nest as deep as you need. Beyond plain arithmetic it handles powers and roots, percentages, factorials, reciprocals, the constants π and e, and the usual trig and log family — sin, cos, tan and their inverses, plus log (base 10) and ln (natural log). One thing worth remembering: trig functions care about your angle mode. Ask for sin(90) in radian mode and you'll get 0.8939, not the 1 you expected, because 90 radians is a very different angle than 90 degrees. If a result looks wrong, that's the first thing to check.

Two small features save a surprising amount of friction. Memory keys (M+, M−, MR, MC) let you park an intermediate number and pull it back later instead of scribbling it on a sticky note. And the history panel keeps your recent calculations within reach — click any past line to drop it straight back into the display and keep building on it. Multi-step work stops being a juggling act.

Converting units without the guesswork

The converter covers eleven categories: length, weight, temperature, area, volume, speed, time, data, pressure, energy and angle. Pick a category, choose the two units, and the answer updates as you type — no Enter required. It moves freely between metric and US/imperial, which is where most everyday mistakes happen.

Why does keeping units consistent matter so much? Because mixing them quietly breaks things. A recipe from a US blog asks for 2 cups of flour; your kitchen scale reads grams. Guess, and the bread comes out wrong. Convert, and it's about 240 grams and you move on. Or you're booking a hotel abroad and the forecast says 30°C — is that beach weather or a coat? Drop it in and you'll see roughly 86°F, which settles the argument. The same logic scales up: engineers and students lose marks (and worse) when pounds sneak into a metric formula. The converter's whole point is to take that risk off the table. Temperature gets special handling, by the way — it's not a simple multiply like the others, since each scale starts counting from a different zero.

Speed conversions show up more than you'd think: a car spec in mph, a running pace in km/h, wind in knots. Data sizes too — knowing a 4 GB file is roughly 4,000 MB helps when a download bar is creeping along and you're wondering if you've got room.

The money calculators are the ones that pay off

Arithmetic is handy; financial math is where small inputs swing big outcomes. The page links to a set of focused tools, and each one answers a real question. The compound interest calculator shows how interest earned on interest snowballs over time — it's the difference between guessing whether saving is worth it and actually seeing the curve. There's a loan and mortgage calculator for working out a monthly payment before you sign anything, an inflation tool that tells you what today's money will really be worth in ten years, and an ROI calculator for sizing up an investment.

For longer horizons there's a FIRE/retirement calculator, a dividend yield tool, a position-averaging helper for anyone managing a portfolio, and a plain percentage calculator for the everyday stuff — tips, discounts, markups. If your numbers cross currencies, the currency converter pairs naturally with these, so a foreign price or salary lands in terms you can reason about.

All of it runs in your browser. Nothing gets uploaded, nothing's stored on a server, and there's no sign-up wall between you and an answer. Open the page, do the math, close the tab — the calculation is yours and it stays on your device. That's the whole idea: fast tools that respect your time and your privacy, available in 40 languages.

Frequently asked questions