The money will go to the British Gas Energy Support Fund to provide grants to customers.
Thousands of households are expected to receive grants of £250-£750.
Last month, Centrica, owner of British Gas, saw its profits rise to £1.34 billion from £262 million recorded in the same period last year.
It is believed to be the first UK energy firm to make this type of commitment amid a very volatile environment for the energy retail market.
“As a responsible business, we want to do more to support our customers during this difficult time. Committing 10% of our profits for the duration of the energy crisis will mean we can target help at those who need it the most.”