Percentage calculator

Every percentage question, worked out.

Nine calculators covering every way a percentage gets asked — plus discounts, tips, tax and margins. Type a number and the answer updates as you go.

What is % of ?

Quick

Result

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Parts per hundred15%

Everyday percentages

Quick tools

The four percentage jobs that come up most often, each with the working shown so you can check it.

Discount

Sale price after a percentage off

Original price

Discount %

You pay—

You save—

Tip

Gratuity, total and split per person

Bill amount

Tip %

Split between

Each pays—

Tip—

Total—

Tax or VAT

Add tax on, or strip it back out

Amount is

Amount

Tax rate %

Gross—

Net—

Tax—

Markup & margin

Two different numbers — see both

Cost

Selling price

Margin—

Markup—

Profit—

Same value, four notations

Percent converter

A percentage is just a fraction with 100 on the bottom. Here it is in every form at once.

Percentage %

Decimal

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Fraction

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Ratio

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1 in

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Show your working

The formulas

Every calculation on this page comes from one of these seven lines.

Percent of a number

result = value × percent ÷ 100

15% of 240 → 240 × 15 ÷ 100 = 36

X is what percent of Y

percent = X ÷ Y × 100

36 of 240 → 36 ÷ 240 × 100 = 15%

X is P% of what

whole = X ÷ (P ÷ 100)

36 is 15% of → 36 ÷ 0.15 = 240

Percentage change

change = (new − old) ÷ old × 100

240 → 288 = (48 ÷ 240) × 100 = +20%

Increase or decrease by

result = value × (1 ± P ÷ 100)

240 up 15% → 240 × 1.15 = 276

Percentage difference

diff = |A − B| ÷ ((A + B) ÷ 2) × 100

240 vs 288 → 48 ÷ 264 × 100 = 18.18%

Percentage points

points = B% − A%

12% → 15% = 3 points, a 25% relative rise

Common values worth memorising

Fraction	Percentage	Decimal	Shortcut
1/2	50%	0.5	Halve it
1/3	33.33%	0.3333	Divide by 3
1/4	25%	0.25	Halve it twice
1/5	20%	0.2	Divide by 5
1/8	12.5%	0.125	Halve it three times
1/10	10%	0.1	Move the decimal one place
1/20	5%	0.05	Take 10%, then halve
1/100	1%	0.01	Move the decimal two places
2/3	66.67%	0.6667	Divide by 3, double it
3/4	75%	0.75	Subtract a quarter

Where people trip up

Common questions

What's the difference between percent and percentage points?

If an interest rate rises from 12% to 15%, that's a rise of 3 percentage points — but a 25% increase in the rate itself, because 3 ÷ 12 = 0.25. Both are correct, and they describe very different-sounding things, which is why headlines so often blur them. The "Percentage points" tab shows both numbers side by side.

Why doesn't a 50% drop cancel out a 50% rise?

Because each percentage is taken from a different starting number. Take 100, drop it 50% and you have 50. Add 50% back and you get 75, not 100. To undo a 50% fall you need a 100% rise. The rule: to reverse a drop of P%, you need a rise of P ÷ (100 − P) × 100%.

Percentage change or percentage difference — which do I want?

Change has a direction: you're going from an old value to a new one, so you divide by the old value. Difference has no direction: you're comparing two things that both just exist, so you divide by their average. Change from 240 to 288 is 20%. The difference between 240 and 288 is 18.18%, and it stays 18.18% whichever way round you write them.

How do I take tax out of a price that already includes it?

Don't subtract the percentage — divide. At a 20% rate, a £120 gross price is 120 ÷ 1.20 = £100 net, with £20 tax. Subtracting 20% would wrongly give you £96. The Tax tool handles both directions; switch "Amount is" to tax included.

Markup and margin both say 40% — why are they different amounts?

Markup is profit measured against cost; margin is profit measured against selling price. An item costing 60 sold at 100 carries a 66.67% markup but a 40% margin. Margin can never exceed 100%; markup has no ceiling. Quoting one when you mean the other is a fast way to underprice.

Can a percentage be more than 100?

Yes. 100% is simply the whole thing, so 250% is two and a half times it. That's normal for growth figures and multipliers. When a result goes past 100 here, the hundred-square fills completely and a tag tells you how many whole hundreds are involved.

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