Percentage Change Calculator

Old number, new number, the change between them.

FREE · NO SIGN-UP · RUNS ON YOUR DEVICE

Your numbers stay on your device

  • 2NUMBERS IN
  • 1ANSWER OUT
  • 6DECIMAL PLACES
  • 0SIGN-UP
Specification

Percentage Change Calculator at a glance

Percent change
From one figure to another
The other three questions
Of, is-of, add or take off
Precision
6 decimal places
Working
Shown beside the answer
Price
Free
Account required
None
Where it runs
On your device
How to

How to use Percentage Change Calculator

  1. 1

    Pick percent change

    Pick percent change.

  2. 2

    Put in both figures

    Enter old, then new.

  3. 3

    Copy the answer

    Copy the answer.

Questions

Frequently asked questions

What is the percentage change from 80 to 100?

A rise of twenty-five percent. The twenty that was added is measured against the eighty you started from, not against the hundred you ended on.

Why is a rise then an equal fall not back to the start?

The fall comes off a bigger number. A hundred up fifty percent is a hundred and fifty; that same figure down fifty percent is seventy-five.

Is this the same as percentage points?

No. Four percent to six percent is two percentage points and a fifty percent change. This question gives you the percent change.

Which number goes first?

The old one. Putting them the other way round measures the move from the new figure, which answers a different question.

Background

Where percent change goes wrong

Percent change is one of the four questions on this panel. Choose it, put the old figure and the new figure in, and the answer says how far it moved and which way.

  • Measuring the change against the new figure instead of the old one.
  • Reading a large percentage from a small base as though it were a large move.
  • Rounding at every step instead of once at the end.
  • Treating a change in a percentage as a percentage change, when they are different things.

Full specification

Specification of the Percentage Change Calculator tool
Percent changeCompares a new number against the old one and says whether it went up or down.
The other three questionsA share of a number, one number as a percent of another, and adding or taking off a percentage.
PrecisionSix decimal places are kept, so a chain of steps does not drift.
WorkingThe arithmetic is shown beside the answer, not only the result.
PriceFree. Supported by clearly labelled ads placed outside the working area.
Account requiredNo.
Where it runsIn your browser tab. Nothing is sent anywhere.
Next step

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