Rate Constant Calculator (k from Half-Life)

Convert half-life (t½) to the rate constant (k) for common reaction orders.

Inputs Reaction settings

Reaction order

0th order k units: concentration/time 1st order (default) k units: 1/time 2nd order k units: 1/(concentration·time)

Half-life (t½)

Must be numeric and > 0.

Initial concentration ([A]₀)

Shown for 0th and 2nd order only.

Custom unit label

Required when “custom” is selected (max 16 characters).

Options Steps

Show Steps

ln(2) = 0.6931471805599453

Rate constant

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Units

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Equation used

Order

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Equation

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Common conversions

Note

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Inputs

t½

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[A]₀

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