How it works

Pick a screen at the top, tap a box and type on the keypad. The answer updates as you type. Use ± for negative numbers and Next to jump to the other box.

% of: X% of Y = X ÷ 100 × Y. 15% of 80 = 12.
What %: X is what % of Y = X ÷ Y × 100. 12 is 15% of 80. Y can't be 0.
% change: (B − A) ÷ |A| × 100. From 50 to 75 is +50%; from 75 to 50 is −33.33%. A can't be 0. When A is negative, the sign still shows the direction: −50 to −25 is up 50%.
+ / − %: Y + X% = Y × (1 + X ÷ 100) for tax, tip or markup; Y − X% = Y × (1 − X ÷ 100) for a discount. 100 + 8.25% = 108.25; 80 − 25% = 60.

Answers show up to 4 decimal places. Nothing you type leaves your device.

FAQ

Why isn't a 50% rise followed by a 50% drop back to the start?

The second percent applies to a bigger number. 100 + 50% = 150, and 150 − 50% = 75.

How do I remove sales tax from a total?

Tap ☰ More, then Price before tax or discount. 108.25 with 8.25% tax was 100 before tax. Dividing by 1.0825 is correct; subtracting 8.25% of the total is not.

Does it work offline?

Yes. After the first visit the calculator is saved on your device.

Percentage

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Price before tax or discount

Margin and markup

How it works

FAQ