Half-Life Calculator

Compute radioactive decay, remaining isotope quantities, and elapsed half-lives across scientific applications.

Remaining Quantity

25.0000

Decayed Quantity

75.0000

Number of Half-Lives

2.0000

Formula

N(t) = N₀ × (1/2)^(t/t½)

How to Use the Half-Life Calculator

  1. Enter the initial substance quantity (N₀).
  2. Enter the half-life period (t½) of the substance.
  3. Enter the total elapsed time duration (t).
  4. View the remaining quantity, decayed mass, and total half-lives passed.

Formulas & Principles

Decay Formula: N(t) = N₀ × (1/2)^(t / t½)

Decay Constant: λ = ln(2) / t½ ≈ 0.69315 / t½

Alternative Form: N(t) = N₀ × e^(-λt)

Number of Half-Lives: n = t / t½

Frequently Asked Questions

What is half-life in physics and chemistry?

Half-life is the time required for half the radioactive nuclei in a sample to undergo decay into a more stable state.

Does temperature or pressure alter half-life?

No. Nuclear half-lives are intrinsic nuclear properties governed by weak and strong nuclear forces and are independent of chemical bonds, temperature, or pressure.

How is half-life used in carbon dating?

Carbon-14 has a half-life of 5,730 years. By measuring the remaining ratio of Carbon-14 to Carbon-12 in organic matter, scientists determine archaeological age.

Why this calculator matters

This calculator helps solve mathematical problems faster and with fewer manual arithmetic mistakes. It is useful for studying, research verification, technical engineering checks, and everyday problem-solving.

When to use it

Use it when you need a fast answer, a cross-check for manual calculations, or a clear step-by-step verification of your result.

Quick tips

Double-check your inputs, keep units consistent across all fields, and verify boundary conditions.