PercentSolver

Percentage Calculator

Three percentage tools in one — solve for the value, the percent, or the change between two numbers. Toggle Show the Math to see exactly how it was done.

No sign-up
Step-by-step working
Instant

X (percent)

Y (value)

18% of 54

9.72

(18 ÷ 100) × 54 = 9.72

1Convert 18% to a decimal → 0.18
2Multiply by 54 → 0.18 × 54
3Result → 9.72

Tip: use "Copy link" above to share this exact calculation — your inputs are saved in the URL.

What common percentages come to on everyday amounts

Each cell is the answer the 'What is X% of Y?' mode returns: the percentage in the left column applied to the dollar amount in the header. Rounded to the cent.

Percentage	of $25	of $50	of $100	of $1,000
5%	$1.25	$2.50	$5.00	$50.00
8%	$2.00	$4.00	$8.00	$80.00
10%	$2.50	$5.00	$10.00	$100.00
15%	$3.75	$7.50	$15.00	$150.00
18%	$4.50	$9.00	$18.00	$180.00
20%	$5.00	$10.00	$20.00	$200.00
25%	$6.25	$12.50	$25.00	$250.00
30%	$7.50	$15.00	$30.00	$300.00
50%	$12.50	$25.00	$50.00	$500.00
75%	$18.75	$37.50	$75.00	$750.00

The formula is the same for tips, sales tax and discounts: (percent / 100) x amount. For a discount, subtract the cell value from the amount; for a tip or tax, add it. To go the other way and recover a pre-tax price from a total, use the 'X is what % of Y?' mode or divide by (1 + rate) rather than subtracting the percentage.

What is X% of Y?

(X ÷ 100) × Y

Use this when you know a percentage and need to find the share of a total — e.g. 18% tip on a $54 bill.

X is what % of Y?

(X ÷ Y) × 100

Use this when you have two numbers and want to know one as a percentage of the other — e.g. 7 right out of 10.

% change from X to Y

((Y − X) ÷ |X|) × 100

Use this for growth or discount comparisons — e.g. the price went from $80 to $60.

Worked example: a 25% discount

A $120 jacket is marked 25% off. First find the discount: (25 ÷ 100) × 120 = $30. Subtract it from the original: 120 − 30 = $90. To check the reverse, confirm that $90 is 75% of $120: (90 ÷ 120) × 100 = 75%. If you only know the sale price and the discount rate, divide instead of subtract — 90 ÷ 0.75 = $120 recovers the original.

Common percentage mistakes

Confusing percentage points with percent change — 4% to 6% is 2 points, but a 50% increase.
Reversing a percentage by subtracting instead of dividing by (1 + rate).
Adding percentages of different totals as if they share one base.
Assuming a 25% drop then a 25% rise returns you to the start — it doesn't.

Frequently asked questions

How do I calculate a percentage of a number?

Divide the percentage by 100, then multiply by the number: (X ÷ 100) × Y. For example, 18% of $54 is (18 ÷ 100) × 54 = $9.72. Use the 'What is X% of Y?' mode above and it shows each step.

How do I find what percentage one number is of another?

Divide the part by the whole and multiply by 100: (part ÷ whole) × 100. For example, 7 out of 10 is (7 ÷ 10) × 100 = 70%. This is the 'X is what % of Y?' mode.

How do I calculate a percentage increase or decrease?

Subtract the old value from the new value, divide by the old value, and multiply by 100: ((new − old) ÷ |old|) × 100. Going from $80 to $60 is ((60 − 80) ÷ 80) × 100 = −25%, a 25% decrease.

What's the difference between a percentage and a percentage point?

A percentage point is an absolute difference between two percentages; a percentage change is relative. If a rate rises from 4% to 6%, that's a 2 percentage-point increase but a 50% relative increase. Mixing the two is one of the most common percentage mistakes.

How do I reverse a percentage to find the original amount?

If a price already includes a change, divide rather than subtract. For a total of $120 that includes 20% tax, the original is 120 ÷ 1.20 = $100 — not 120 − 20%. Dividing by (1 + rate) undoes an increase; dividing by (1 − rate) undoes a discount.