Negotiable Instruments Act, 1881
79. Interest when rate specified
When interest at a specified rate is expressly made payable on a
promissory note or bill of exchange, interest shall be calculated at the rate
specified, on the amount of the principal money due thereon, from the date of
the instrument, until tender or realization of such amount, or until such date
after the institution of a suit to recover such amount as the court directs.