Reaction Half-Life Calculator

t₁/₂ for 1st and 2nd order

⏱

Reaction Half-Life

t₁/₂ for 1st and 2nd order

$$t_{1/2}^{(1)}=\dfrac{\ln2}{k}\qquad t_{1/2}^{(2)}=\dfrac{1}{kC_{A0}}$$

1st order half-life is concentration-independent. 2nd order depends on $C_{A0}$.

k (s⁻¹ for 1st order)

C_A0 (mol/m³)

All fields required; k and C_A0 nonzero.

Half-Life (1st / 2nd order)

—

📄 Free Download

Get the WTF Formula Sheet

Every equation from all 6 topics in one clean PDF. Made for exams, problem sets, and the moments when you have no idea what the flux is going on.

✓ You're in — check your inbox for the formula sheet.