Percentage Calculator

About the percentage calculator

This free percentage calculator answers the five everyday percentage questions from plain numbers. Pick a question, enter your numbers, and it returns the result, the inputs echoed back, and a one-line summary.

Everything runs locally in your browser. Nothing is uploaded to a server, and it works offline once the page has loaded.

What it can work out

• Percent of a number (percent_of) — what is percent% of base? e.g. 15% of 200 = 30.
• What percent (what_percent) — part is what percent of whole? e.g. 30 is 15% of 200.
• Percent change (change) — the percent increase or decrease from from to to, plus the absolute change. e.g. 200 → 230 is a 15% increase.
• Apply a change (apply_change) — increase or decrease base by percent% (use a negative percent to decrease). e.g. 200 increased by 15% = 230.
• Share of a total (percent_of_total) — value is what percent of total, plus the remaining amount and remaining percent. e.g. 30 of 200 is 15%, leaving 170 (85%).

Examples

• percent_of, percent = 15, base = 200 → 30
• what_percent, part = 30, whole = 200 → 15%
• change, from = 200, to = 230 → 15% increase (absolute change 30)
• apply_change, base = 80, percent = -25 → 60
• percent_of_total, value = 30, total = 200 → 15% (remaining 85%)

How the values are computed

Standard arithmetic is used throughout — percent_of is percent/100 · base, what_percent is part/whole · 100, change is (to − from)/from · 100, apply_change is base · (1 + percent/100), and percent_of_total is value/total · 100. Inputs may be negative; only divisors (whole, from, total) must be non-zero. Results are rounded to six decimal places.

FAQ