Annual, monthly and daily loan rates: how to convert them

The rate period must match the calculation period. Using an annual rate as though it applied each month produces a radically incorrect payment.

The conversions below are simple nominal estimates. A contract may use a different day-count convention, an effective rate or product-specific methodology.

Annual to monthly

simple monthly rate = nominal annual rate / 12

For 24% annually:

24% / 12 = 2% = 0.02 per month

This monthly rate can be multiplied by the outstanding balance to estimate one month’s interest.

Annual to daily

Simple day-count conventions commonly divide by either 360 or 365:

24% / 360 = approximately 0.0667% per day
24% / 365 = approximately 0.0658% per day

Neither basis is universal. Use the convention specified in the contract and applicable market.

Example on a $50,000 balance

Monthly estimate:

50000 x 0.02 = 1000

Daily estimate on a 360-day basis:

24% / 360 = 0.0667%
50000 x 0.000667 = approximately 33.33

Taxes, fees, dates and rounding may change a formal calculation.

Common period errors

Entering a 2% monthly rate into a field that expects an annual rate understates the cost; applying 24% every month overstates it dramatically. Before calculating, confirm:

• Is the rate annual, monthly, biweekly or daily?
• Is it nominal or effective?
• Does it represent interest alone or a broader cost metric?
• Which rate period does the calculator require?

The loan calculator expects an annual rate and converts it internally for monthly amortization. If you have an effective rate, review nominal vs. effective interest rates before converting it.

Frequently asked questions

Can I divide an annual rate by 12?

Yes for a simple nominal monthly estimate. Follow the contract’s methodology for a formal calculation.

Does a daily rate use 360 or 365 days?

It depends on the contract, product and jurisdiction. Never assume one convention applies universally.