Percentage guide: amount, change or share of a total

When this tool helps

“Find the percentage” can describe three different questions. Choosing the mode first gives the two fields a clear meaning and prevents a correct formula being used for the wrong task. The candidate offers Percentage of a number, Percentage change and What percentage?

Use the first mode for a portion such as 15% of 200. Use Percentage change when comparing an original and new value. Use What percentage? when you already know a part and its total. All three calculations run locally without interpreting a written question.

What to enter

These are the candidate Android fields, not a form on this website. Editable fields in the app start empty; modes and units are selected separately.

What would you like to find?: Select the percentage mode.
Number / Original value / Part: Meaning changes with the selected mode.
Percentage (%) / New value / Total: Enter the second value required by that mode.

Worked example · not prefilled app data

Try this example after the update is available

The values below explain the calculation. They are not a quote, a live measurement or an automatic answer for your situation.

Mode: Percentage of a number
Number: 200
Percentage (%): 15

Checked example result30

Fifteen percent is fifteen hundredths. Multiplying 200 by 15 and dividing by 100 gives 30.

Formula and assumptions

Percentage amount = number × percentage ÷ 100

Percentage change uses (new − original) ÷ |original| × 100. With a positive original value, moving from 80 to 100 is a 25% increase.
What percentage? uses part ÷ total × 100. Negative values can be entered, but their meaning depends on your situation.

A common mistake to avoid

Keep the denominator clear. A change from 80 to 100 is measured against 80, not against 100. Percentage points and percentage change are different ideas.

Find this tool in the Android update

When you have the redesigned Android update, open Tools and search for Percentage, or find it under Numbers.
Open the tool, choose the mode or units relevant to your task, then enter your own values.
Review the result and explanation. Use Calculate & save only if you want the calculation kept in local History; Copy result does not send it to our server.

This guide is an educational preview of the update in testing, not an announcement that Google Play has approved or published it. Calculations are in the native app; no web calculator or download is offered on this page.

Questions about Percentage

Can I calculate percentage change from zero?

No. The original value cannot be zero because it is the denominator of the change calculation.

Can the share of a total exceed 100%?

Yes. A part larger than a non-zero total produces more than 100%. The tool does not assume that every input is a bounded survey share.