Half-Life Calculator

Use the free online Half-Life Calculator tool. Fast, private and easy to use — runs entirely in your browser. Part of our Chemistry Calculators collection.

Molarity Calculator

Solute mass (g) Molar mass (g/mol) Solution volume (L)

Find the molar concentration of a solution from solute mass, molar mass and volume.

Dilution Calculator

Stock concentration C1 Target concentration C2 Final volume V2

Use C1V1 = C2V2 to find how much stock solution and diluent a dilution needs.

pH Calculator

[H+] concentration (mol/L) or pH (leave [H+] blank)

Convert between hydrogen-ion concentration, pH and pOH in both directions.

Ideal Gas Law Calculator

Pressure P (atm) Volume V (L) — leave blank to solve Moles n Temperature T (K)

Solve PV = nRT for the missing variable using R = 0.082057 L·atm/mol·K.

Grams to Moles Converter

Molar mass (g/mol) Mass (g) or Moles (leave mass blank)

Convert between grams and moles of any substance using its molar mass.

Combined Gas Law Calculator

Initial pressure P1 Initial volume V1 Initial temperature T1 (K) Final volume V2 (or leave blank) Final pressure P2 (or leave blank) Final temperature T2 (K)

Apply P1V1/T1 = P2V2/T2 to find the final pressure or volume of a gas.

Half-Life Calculator

Initial amount Half-life Elapsed time (same unit)

Find how much of a decaying substance remains after any elapsed time.

Solution Percentage Calculator

Solute mass (g) Solution volume (mL)

Express a solution strength as % w/v and grams per litre.

Frequently Asked Questions

Is the Half-Life Calculator free to use?

Yes. The Half-Life Calculator is completely free with no sign-up, no limits and no watermarks. You can use it as many times as you like.

Is the Half-Life Calculator safe and private?

Absolutely. The Half-Life Calculator runs entirely in your browser, so your data never leaves your device and nothing is uploaded to a server.

Do I need to install anything to use the Half-Life Calculator?

No installation is needed. The Half-Life Calculator works instantly online in any modern browser on desktop, tablet or mobile.

Does the Half-Life Calculator work on mobile phones?

Yes. The Half-Life Calculator is fully responsive and works smoothly on iPhone, Android and any other device.