Get started

smoot is a calculating notepad. You write lines of arithmetic the way you would write notes, and every line shows its answer. Numbers carry units, money, and dates, and a mistake between them is an error rather than a wrong number.

This block is live. Change a number and the answers update.

coffees = $4.50 * 20
train pass = $89
coffees + train pass
flight = 5541 km to miles to 0 dp
@2026-12-25 - today to days

What it does

• Units. 100 km / 2 hour is a speed; 5 m + 3 kg is an error. Conversions are one word: 60 mph to kph, 80 kg to imperial.
• Money. $, £, €, ¥ and thirty ISO codes, with daily rates. dinner + 18% keeps the currency.
• Dates. @2026-01-31 + 1 month lands on the 28th. Time zones and daylight saving are handled per date.
• Exact arithmetic. 0.1 + 0.2 == 0.3 is true.
• Names that are phrases. monthly rent = 1350, then monthly rent * 12.
• Formulas that run backwards. Put distance = speed * time in a formula once and ask for any of the three.
• An equation solver. solve for x: 3 * x + 1 = 10, with units, through powers and trigonometry.

Get started

1. Open smoot.app. Nothing to install or sign up for.
2. Type a line such as 8 oz to grams or £86.40 / 4. The answer appears beside it.
3. Read the reference for the whole language and the worked examples for problems solved end to end.

Documents save in your browser. Share copies a link that carries the text.

Rough edges

The solver cannot yet handle an unknown at two different powers, as in x^2 + x = 6, and gives only the positive root of x^2 = 9. A note that mentions a unit or a name you have defined is read as arithmetic, so start such notes with #.