Everyday math and percentages
Work out tips, discounts, splits, totals, ratios, and markups with expressions that read like the question in your head.
245 * 15%
86 + 15%
250 - 30%
calcul.io / the editable calculator
Free online calculator.
More than simple math: Calcul.io handles unit conversions, variables, functions, dates, and money in one editable workspace.
free to use
no account required
shareable calculations
bill = 86
tip = bill * 18%
total = bill + tip
5 km to miles
Edit a line. Everything below updates.
Type the question the way you think about it.
Calcul.io stays useful when a calculation stops being one neat equation. Each line keeps its expression beside its result, so you can check any step, change it, and see the effect without starting over.
Unit conversion without the detour
Convert length, mass, temperature, area, volume, speed, digital data, and other supported units by naming the target unit.
5 km to miles
180 lb to kg
3 cups to ml
Dates, times, and durations
Add days to a date, compare calendar intervals, and keep a time calculation readable instead of translating it into seconds first.
today + 30 days
90 days ago
8 hours + 45 minutes
Currencies, stocks, and crypto
Use supported currency codes, stock tickers, and cryptocurrency symbols in the same workspace as the rest of your budget or estimate.
1 BTC to AAPL
0.5 BTC to USD
1 AAPL + 10 MSFT to USD
Advanced math, functions, and constants
Go further with algebra, trigonometry, statistics, matrices, probability, complex numbers, built-in constants, and named variables.
round(hypot(3, 4) * sin(pi / 2), 3)
derivative("x^3 + 2x", "x")
sqrt(-4)
net = 2400
vat = 19%
net + net * vat
Edit a value above. The final line keeps up.
Change a line. The rest follows.
Most quick calculators hand you an answer and forget it. Calcul.io keeps every step beside the final number, so you can reuse a value further down and update it whenever the real-world detail changes.
- 1
Write an expression. Start with plain arithmetic or a supported function.
- 2
Give a value a name. Reuse a bill, rate, distance, or any other number further down.
- 3
Share the whole calculation. The URL keeps the lines together for a later check.
Start from a calculation that works.
Pick a worked example, replace the sample values with your own, and keep the reference pages nearby for syntax when you need a closer look.
A calculator should explain itself.
Is Calcul.io free to use?
Yes. Calcul.io is free to use and does not require an account. It runs in a browser, so you can start with a blank calculation whenever you need it.
What can I type into Calcul.io?
You can enter arithmetic, percentages, variables, supported math functions, unit conversions, dates, currencies, and supported stock or cryptocurrency symbols. Start with a simple expression and build from there.
Can I use more than one line?
Yes. Lines run top to bottom, and each one keeps its result beside it. Name a value on one line and use it again below, or keep intermediate steps visible so you can check them.
How do unit conversions work?
Write a value with its source unit and name the target unit, such as 5 km to miles. Calcul.io converts compatible units and keeps the expression editable.
Can I calculate dates and times?
Yes. Calcul.io supports date arithmetic, time calculations, and durations. Expressions such as today + 30 days keep the calendar operation readable.
Can I share a calculation?
Yes. Calcul.io stores the calculation lines in the page URL, so you can copy the link and reopen the same work later or send it to someone else.