Monthly compounding
A = P(1 + r / 12) ^ (12t)Monthly compounding is common for planning examples and recurring contribution schedules.
Compounding comparison
Monthly vs daily compounding
Daily compounding gives interest more chances to earn interest, but the difference can be modest. Use the full calculator to compare monthly and daily results with the same starting amount, deposits, rate, and years.
Daily compounding
A = P(1 + r / 365) ^ (365t)Daily compounding is common for bank interest and money market examples, especially when APY is advertised.
Decision checklist
Compare the whole account, not only the formula.
APY
APY already includes compounding, which makes it the cleaner headline comparison.
Deposit schedule
Monthly deposits, one-time deposits, and irregular deposits can produce different curves.
Fees and rules
Fees, minimum balances, and withdrawal restrictions can erase a small compounding advantage.
Decision guide
Decide whether frequency is material
Holding the nominal rate constant, more frequent compounding produces a slightly higher effective yield. Holding APY constant, the consumer outcome is already normalized and the nominal rates differ. Compare products on the same basis before deciding that daily compounding is automatically better.
The one-year difference can be small
At a 5% nominal rate on $10,000, monthly compounding produces about $10,511.62 after one year and daily compounding about $10,512.67. A monthly fee, a rate that drops after an introductory period, or a minimum-balance condition can outweigh that difference.
Before you decide
- Compare APY to APY, not APY to nominal rate.
- Use the same starting balance and time period.
- Check whether interest remains on deposit.
- Read tier, fee, and withdrawal conditions.
Method and limitations
The comparison isolates compounding frequency. Real products can differ in rate, balance method, crediting schedule, and fees. Regulation DD defines APY to support more consistent comparison, including special rules for tiered and stepped accounts that a simple frequency formula cannot recreate.