Percentage Calculator

Three everyday percentage problems in one. Pick a mode, type two numbers, and read the answer — plus the formula that produced it. Pure client-side math; nothing is uploaded.

Percent

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Quick reference — common percentages

Percent	of 100	Fraction
10%	10	1/10
12.5%	12.5	1/8
20%	20	1/5
25%	25	1/4
33.33%	33.33	1/3
50%	50	1/2
66.67%	66.67	2/3
75%	75	3/4
80%	80	4/5

To compute a percentage of a number in your head: shift the decimal. 10% of 84.50 = 8.45 (one decimal left); 1% = 0.845; 18% = 10% × 1.8 ≈ 8.45 × 1.8 = 15.21.