What daily compounding actually adds
Daily compounding means interest is calculated and added to the balance 365 times a year, so each day's interest earns interest from the next day onward.
The effect is real but smaller than the phrase suggests. At a nominal 8%:
- Yearly compounding gives an effective rate of exactly 8.000%
- Monthly gives 8.300%
- Daily gives 8.328%
Moving from yearly to daily adds about a third of a percentage point. Worth having, not worth reorganising your finances for — and considerably less important than the rate itself, the amount, or the time.
The calculator shows the effective annual rate for exactly this reason. It is the number that lets you compare two products whose compounding conventions differ.
The formula
Where P is the principal, r the annual rate, n the compounding periods per year (365 for daily), and t the time in years.
₹10,000 at 8% compounded daily for five years reaches about ₹14,918, against ₹14,693 compounded yearly — a difference of roughly ₹225 on that sum.
There is a limit
Compounding more often always helps, but with rapidly diminishing returns. As the frequency approaches infinity the result converges on continuous compounding, given by A = Pert.
At 8%, continuous compounding gives an effective rate of 8.329% — barely more than daily's 8.328%. So daily is already, for practical purposes, at the ceiling. Any product advertising "hourly" or "per-second" compounding is marketing rather than mathematics.
Deposits change the picture more than frequency does
Add a recurring deposit above and watch which lever actually moves the outcome.
On ₹10,000 over five years at 8%, switching from yearly to daily compounding adds a couple of hundred rupees. Adding ₹100 a month adds several thousand. The contribution dominates the compounding convention by an order of magnitude, which is the useful lesson hiding in this calculator.
Where daily compounding genuinely applies
Savings accounts commonly accrue daily and credit monthly or quarterly. Many money market and liquid funds accrue daily. Credit cards typically compound daily too — which is the same mechanism running against you, and at 24–42% it does far more damage than 8% does good.
Fixed deposits in India usually compound quarterly rather than daily, so use the frequency selector to match your actual product rather than assuming.
Frequently asked questions
How is daily compound interest calculated?
Using A = P(1 + r/n)^(nt) with n = 365. Rs 10,000 at 8% compounded daily for five years reaches about Rs 14,918, compared with Rs 14,693 compounded yearly.
How much more does daily compounding earn than monthly?
Very little. At a nominal 8%, monthly compounding gives an effective annual rate of 8.300% and daily gives 8.328% - a difference of under three hundredths of a percentage point. The rate, the amount and the time all matter far more.
What is the effective annual rate?
The rate that accounts for compounding frequency, letting you compare products fairly. A nominal 8% compounded daily has an effective annual rate of 8.328%. When comparing accounts, compare effective rates rather than nominal ones.
Is there a limit to how often interest can compound?
Practically, yes. As frequency increases the result converges on continuous compounding, A = Pe^(rt). At 8% that gives 8.329% against daily's 8.328%, so daily compounding is already at the ceiling for all practical purposes.