Does the math and shows its work.

Most calculators hand you an answer and forget it. 1+1 keeps a running tape of every step — tap any line to bring it back.

Show your work

See every step, not just the answer.

Tap any calculation to unfold it into clean, numbered steps — every operation, in the right order. Hit Use to drop a past answer straight back into the keypad.

Calculators in tabs

Keep separate calculations side by side.

Open a tab per job and switch between them like browser tabs — each with its own running tape and a smart memory bank, where the values you reuse most bubble to the front.

VAT, GST & sales tax

Net, VAT, gross — solve any one from the others.

Enter any field and the other two derive instantly, with the rate prefilled for your region.

Tip & split

Compare every tip at once.

Enter the bill and split, then compare several tip rates side by side — each row showing the tip, total, and amount per person. Edit any percentage, or add your own.

Scientific

Trig, logs, powers, and roots.

A full scientific calculator for the harder problems — sine, cosine, and tangent, logarithms, exponents, and roots, right alongside the everyday keys.

Budget & trip

Plan what you spend.

Budget and trip-budget planners track your income and expenses by category — including a trip mode with travel, lodging, and per-day costs.

Interest

See how savings grow.

Enter a principal, rate, and term to project compound growth over time — with a growth curve and a year-by-year breakdown.

FIRE

Your path to financial independence.

Estimate your FIRE number and how many years it takes to reach it — from your income, expenses, and savings rate.

iPad

Two calculators, side by side.

On iPad, run a full Split View and drag tabs between panes.

No ads. No tracking.

Just a fast, honest calculator.

Get 1+1 Calculator.