Everyday arithmetic

Percentage change calculator

Use the original value as the denominator. A negative result means a decrease.

Your numbers

Use the units shown. Results update as you change valid inputs.

YOUR RESULT

Use the original value as the denominator. A negative result means a decrease.

THE NUMBERS, EXPLAINED

How to use this calculator.

Use the original value as the denominator. A negative result means a decrease.

Start with your inputs

Enter original value, new value. Keep amounts in the units shown on each field. The example is a starting point, not a recommended value.

InputExample value
Original value80
New value100

A worked example

With the example inputs above, change (%) is 25. Change the inputs to explore your own scenario.

Putting the example numbers into the formula

Change (%)
((100)-(80)) ÷ (80) × 100 = 25

Absolute change
(100)-(80) = 20

All results for the example inputs above
ResultExample answer
Change (%)25
Absolute change20

How this is calculated

Change (%)

(b-a) ÷ a × 100

Absolute change

b-a

Symbols and units
a
Original value
b
New value

Use the units shown. A list keeps the order in which you enter its values. The symbol ^ means “raised to the power of”.

Assumptions and limits

Use the original value as the denominator. A negative result means a decrease.

Calculations use the values you enter. Blank or invalid inputs show an error instead of silently substituting zero. Results are displayed to useful precision; calculations retain the underlying numeric precision.

Questions about this tool

What does the result tell me?

Change (%); Absolute change. The result applies to the method and inputs described above. Check the units and assumptions before using it in a decision.

Why might another calculator differ?

Differences in units, rounding, timing or model definitions can produce different answers. Compare the input definitions and the method, rather than only the final number. For this tool: Use the original value as the denominator. A negative result means a decrease.

Are my inputs stored or sent to AI?

Calculations on this page happen in your browser. The separate AI question finder sends its submitted conversation to OpenAI; these calculator fields are not sent. Favourites and recent tool names are stored locally. A shared link contains the inputs you choose to include.

Further reading

OpenStax: Prealgebra ↗

Background reading; this does not imply endorsement or independent review of SumFizz.

Review status

Software example and browser checks are recorded in our quality report. No external expert review is claimed. Created with coding assistance; calculations run as ordinary browser code.

Read the quality report →