Compound Interest Calculator · Practical guide
Daily vs. Monthly Compounding
How much compounding frequency actually changes your final balance — less than you think.
At a glance
The Short Answer
Surprisingly little. On $10,000 at a 7% nominal rate held for 20 years, daily compounding returns $40,546.56 versus $40,387.39 for monthly — a difference of just $159.17 over two decades.
Interactive tool
Compound Interest Calculator
Enter your own values, then compare the result with the examples below.
Growth Summary
Year-by-Year Breakdown
| Year | Start Balance | Contributions | Interest | End Balance |
|---|
The Full Frequency Ladder
Same $10,000, same 7% nominal rate, same 20 years — only the compounding schedule changes:
| Frequency | Final Balance | Effective Annual Rate |
|---|---|---|
| Annual | $38,696.84 | 7.00% |
| Semiannual | $39,592.60 | 7.12% |
| Quarterly | $40,063.92 | 7.19% |
| Monthly | $40,387.39 | 7.23% |
| Daily | $40,546.56 | 7.25% |
| Continuous | $40,552.00 | 7.25% |
Why the Gains Shrink
Each increase in frequency adds interest-on-interest sooner, but by smaller and smaller margins. Moving from annual to monthly compounding adds $1,690.55; monthly to daily adds only $159.17; and continuous compounding — the theoretical limit given by A = Pe^(rt) — beats daily by a mere $5.44.
What Actually Moves the Needle
The rate and the time horizon dwarf frequency effects. One extra percentage point of return adds thousands over 20 years; one extra compounding notch adds tens of dollars. When comparing accounts quoted by nominal rate, frequency matters a little — when quoted by APY, it matters not at all, since APY already folds the schedule in. Test every frequency in the calculator above to see the effect on your own numbers.
Frequently Asked Questions
Should I pick a bank account based on compounding frequency?
No — compare APYs instead. APY already accounts for the compounding schedule, so the higher APY wins regardless of how often interest is credited.
What is continuous compounding?
The theoretical limit where interest compounds infinitely often, computed as A = Pe^(rt). In practice it is nearly identical to daily compounding — just $5.44 apart on $10,000 at 7% over 20 years.
Does frequency matter more at higher rates?
Slightly — the gap between monthly and daily grows with the rate, but it remains small relative to the effect of the rate itself.
Does frequency matter for loans too?
Yes, in reverse: more frequent compounding on a loan means you pay slightly more. The same math applies to credit cards, which typically compound daily.