Work out mortality rate (qx) instantly with clear inputs, formula shown and shareable results.
qₓ is the probability that a life aged exactly x dies before reaching x+1, measured as deaths divided by lives exposed at the start of the year. The central rate mₓ instead divides by mid-year exposure, which is what population statistics usually publish.
Mortality rates
qₓ = dₓ / lₓ; mₓ = dₓ / (lₓ - dₓ/2)
qₓ uses the initial population; mₓ uses average population during the year, so mₓ is slightly the larger of the two.
It drives every life-table quantity — survival curves, annuity factors and life insurance premiums all build up from qₓ.