Build your own calculator

Make a calculator for your own job: name the inputs, write the formulas, and use it right away. Save it on this device or share it with a link.

By the Calcist team · Checked against known answers · Updated October 26, 2026

Shared calculator. Someone made this with Calcist's builder. Calcist hasn't checked its formulas, so treat the results with care.

Start from

Calculator name

Inputs

Results

My calculators

Private: calculated on your device. Nothing you type is sent anywhere.

How to build one

Start from a template or a blank calculator.
Add your inputs. Give each a label people will see, and a short name to use in formulas, like hours or rate.
Add results. Each result is a formula using the input names, like hours * rate. A result can also use earlier results by name.
Try it in the live calculator on the right, then save it or copy a link to share it.

What you can use in formulas

Write	Meaning
`+ − * /`	Add, subtract, multiply, divide
`^`	Power, e.g. `side^2`
`( )`	Brackets to control the order
`ceil( )`, `floor( )`, `round( )`	Round up (whole boxes, gallons), round down, round to nearest
`min(a, b)`, `max(a, b)`	The smaller or larger of two values
`sqrt( )`, `pi`, `abs( )`, `ln( )`, `log( )`	Square root, π, absolute value, logarithms
`x / 100`	Turn a percent input into a decimal (20% → 0.2)

Private and safe

Saved calculators stay in this browser on this device. Nothing is uploaded.
A share link contains the whole design (names and formulas), so anyone with the link can open it. Don't put private information in the names.
Formulas are read by Calcist's own math parser and are never run as code.
Calculators you build aren't checked by Calcist. For important decisions, test them with numbers you can verify by hand.

How we checked this

Before every update, this calculator is run in a real browser with these known answers, and it must match all of them:

Paint template: 400 sq ft, 2 coats, 350 sq ft/gal, $45/gal, 6 h at $55: total $465 ✓

Last checked October 26, 2026. Spotted something wrong? The math is done in your browser with the formula shown on this page, so you can check any result by hand.

Questions people ask

Do I need to know how to code?

No. Formulas use ordinary math, like hours * rate or price * (1 + tax/100).

Where are my calculators saved?

In your browser on this device. Clearing your browser's site data removes them, so copy the share link of any you want to keep safe.

Can I share a calculator?

Yes. Copy share link puts the whole calculator in the link. Anyone who opens it can use it or edit their own copy.

Why does it say Unknown name?

A formula uses a name that isn't one of your inputs or earlier results. Check the spelling in the Name column.

Related calculators

Scientific calculatorsin, cos, logs, powers, roots and more, with a history you can edit.Percentage calculatorPercent of a number, what percent, percent change and more.Profit margin and markupMargin, markup and the price for a target margin.Paint calculatorGallons of paint for a room, after doors and windows.