flat rate
noun [ C ]
ukusa rate that is fixed at a particular level that does not change, however much work is done or however much a service is used:
The only exceptions to this flat rate are calls to 0800 and 0808 numbers.
They were the first to introduce flat-rate pricing for texts and mobile broadband.
a flat-rate contribution
FINANCE
a rate of interest on a loan that is charged on the original amount that was borrowed, not on the amount of debt that is still to be paid back:
If you borrow £5,000 on a 6% flat rate, you will still pay 6% interest on £5,000 in the last year, when most of the loan has already been repaid.
Compare
APR
a rate that is the same for everyone:
Employees will contribute a flat rate of £15 monthly.