What is the difference between adding and removing tax?

Adding tax multiplies up from a pre-tax figure. Removing works backwards from a total that already includes it — which is not the same sum, and the usual mistake is subtracting the percentage from the total.

Can it do percentage increase between two numbers?

Yes — enter both and it gives the change as a percentage, with the direction made clear.

What can it work out?

A percentage of a number, what one number is as a percentage of another, percentage increase and decrease, and the original value before a change.

Why is a 50% rise then a 50% fall not back where it started?

Because the second percentage is taken from a bigger number. 100 rises to 150, then falls by 75 to 75. The calculator shows each step, which is where the intuition breaks.

Percentage Calculator

Six everyday calculations including tax added or removed at a rate you set.

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How to use Percentage Calculator

Pick the calculation you need.
Enter your numbers.
Read the answer, with the working shown so you can check it.

The four percentage questions, and their formulas

What is P% of X?: result = X × P ÷ 100
15% of 240 = 240 × 15 ÷ 100 = 36
X is what percent of Y?: P = X ÷ Y × 100
36 out of 240 = 36 ÷ 240 × 100 = 15%
Percentage change from X to Y: change = (Y − X) ÷ X × 100
200 to 250 = 50 ÷ 200 × 100 = +25%
The original value before a P% change: original = final ÷ (1 + P ÷ 100)
120 after a 20% rise = 120 ÷ 1.2 = 100

Discounts and VAT

You want	Do this	Example
Price after a 20% discount	price × 0.80	£50 → £40
Price before a 20% discount	price ÷ 0.80	£40 → £50
Add 19% VAT (Germany)	net × 1.19	€100 → €119
Remove 19% VAT	gross ÷ 1.19	€119 → €100
Add 20% VAT (UK)	net × 1.20	£100 → £120
Remove 20% VAT	gross ÷ 1.20	£120 → £100

Removing a percentage is division, not subtraction. Taking 20% off £120 gives £96, which is not the price before 20% was added — that was £100.

Questions

What is the difference between adding and removing tax?: Adding tax multiplies up from a pre-tax figure. Removing works backwards from a total that already includes it — which is not the same sum, and the usual mistake is subtracting the percentage from the total.
Can it do percentage increase between two numbers?: Yes — enter both and it gives the change as a percentage, with the direction made clear.
What can it work out?: A percentage of a number, what one number is as a percentage of another, percentage increase and decrease, and the original value before a change.
Why is a 50% rise then a 50% fall not back where it started?: Because the second percentage is taken from a bigger number. 100 rises to 150, then falls by 75 to 75. The calculator shows each step, which is where the intuition breaks.