What does the Half-Life Calculator work out?

Radioactive decay, or anything that halves. It is one of the Math tools on Mondo Knows.

How is the Half-Life Calculator calculated?

The maths is short enough to check by hand: N = N0 x (1/2)^(t / half-life).

Do I need to sign up, and is my data stored?

No sign-up, and nothing you type is sent anywhere. The calculation runs in your own browser, so the figures stay on your device and the page works offline once loaded.

Mondo Knows Tools

Half-Life Calculator

Radioactive decay, or anything that halves. Use the free half-life calculator below to get an instant answer, with the formula shown so you can check the maths and trust the result. Free, private, and no sign-up.

Initial amount

Half-life

years

Elapsed time

years

Mondo says

Remaining

26.8402

Decayed73.1598

Half-lives elapsed1.898

Percent remaining26.84%

The formula

N = N0 x (1/2)^(t / half-life)

Half-Life Calculator: common questions

What does the Half-Life Calculator work out?: Radioactive decay, or anything that halves. It is one of the Math tools on Mondo Knows.
How is the Half-Life Calculator calculated?: The maths is short enough to check by hand: N = N0 x (1/2)^(t / half-life).
Do I need to sign up, and is my data stored?: No sign-up, and nothing you type is sent anywhere. The calculation runs in your own browser, so the figures stay on your device and the page works offline once loaded.

Mondo also knows

Exponent CalculatorPowers and roots, including fractional exponents.➗ Math Log CalculatorLogarithms in any base, natural and common.➗ Math Hex CalculatorConvert between hexadecimal and decimal.➗ Math Least Common Multiple CalculatorThe smallest number a list all divides into.➗ Math

Facts that connect to the half-life calculator

Short, sourced facts that point back to this tool.

Black holes slowly evaporate over time via Hawking radiationQuantum effects near the event horizon cause black holes to lose mass Francium is the rarest naturally occurring element on EarthFewer than thirty grammes of francium exist in the entire terrestrial crust at any time Carbon-14 decay allows dating of ancient organic remainsMeasuring residual radioactive carbon-14 yields ages for organic items up to 50,000 years Ionisation smoke detectors contain a microscopic trace of americiumRadioactive americium ionises air inside sensing chambers to detect smoke particles

Estimates for general guidance only. This is not financial, medical or legal advice. Everything runs in your browser and nothing you type is stored.