Percentage Calculator Pro

Why use this tool?

• The same arithmetic comes up in shopping, invoicing, exam scores and reports, and it is easy to apply it the wrong way round, for example taking 20% off when the question was how much 20% of the price is.
• A percentage increase followed by the same percentage decrease does not return to the starting value; seeing the multiplier makes that clear.
• Prices quoted with tax included need the tax taken back out, which is not the same as subtracting the rate from the total.
• Because the working is displayed, you can check the method before using the number in something that matters.

How to use Percentage Calculator

1. Choose the kind of calculation from the buttons at the top: X% of Y, X is what % of Y, X is Y% of what, % change, Add / subtract %, Discount, Tax / VAT / GST, Tip split or Ratio to %.
2. Fill in the two fields that appear for that mode. Their labels change to match, for example Original price and Discount %.
3. For Tip split, also enter how many people the bill is divided between in Split between.
4. Read the answer under Result. The line beneath it, starting Worked as, shows the formula with your numbers in it.
5. Press Copy to take the labelled results as text.

Features

• Nine calculation modes, each with its own labelled inputs and sample values
• Results update as you type, with no calculate button
• Percentage change shows the increase or decrease, the difference and the multiplier
• Add / subtract % shows both the increased and the decreased value
• Tax mode gives tax on top, the total, and also the net and tax contained in a tax-inclusive amount
• Tip split divides the bill plus tip between the number of people you set
• Clear error messages for impossible cases such as a zero total

Supported formats

Takes plain numbers, including decimals and negatives, with no currency symbol needed. Results are rounded for display to at most two decimal places.

Tips

• For a tax-inclusive price, use the lines in Tax / VAT / GST that start with If that amount already includes tax; the net figure divides by one plus the rate rather than subtracting the rate.
• Percentage change measures against the starting value, so going from 200 to 100 is a 50% decrease but going from 100 back to 200 is a 100% increase.
• Use Reverse mode, X is Y% of what, to find an original price when you only know the sale amount and the percentage it represents.
• The modes keep their own values while you switch between them, so you can compare two calculations without retyping.

Frequently asked questions