How we worked it out
Updated as you change the numbers.
- N(t) = N₀ × (1/2)^(t ÷ half-life). Rearranged: half-life = t × ln 2 ÷ ln(N₀ ÷ N), and t = half-life × ln(N₀ ÷ N) ÷ ln 2.
Method and assumptions
Exponential decay: after each half-life, half of what remains is left. The decay constant is λ = ln 2 ÷ half-life, and N(t) = N₀e^(−λt).
Questions
How much carbon-14 is left after 10,000 years?
With a half-life of 5,730 years, about 29.8% of the original.
Sources
Method and figures checked on . Every worked answer on this page is covered by an automated test. Found a mistake? Tell us.