๐Compound Interest / Savings Calculator
Enter principal, rate, and term to compute maturity with compounding. Supports lump-sum deposit and monthly contribution modes. Useful for retirement modeling, education savings plans, long-term return estimates, and simple-vs-compound comparisons.
How to use
- 1Enter principal (or monthly contribution), annual rate, and term.
- 2Pick compounding frequency (annual/monthly).
- 3View maturity amount and total interest.
FAQ
Are taxes included?+
Gross amounts. Subtract Korea's 15.4% interest tax separately. For exact net values, use the [Savings/Deposit Calculator].
Compound vs. simple?+
Simple: interest on principal only. Compound: interest on interest too. โฉ10M @ 5% for 10 years: simple โฉ15M, monthly compound ~โฉ16.48M.
Aren't Korean savings simple-interest?+
Yes โ most Korean bank savings use simple interest. For compounding, roll over after maturity or use the [Savings/Deposit Calculator] in simple mode.
Can rates vary year by year?+
Currently fixed-rate only. For variable rates, simulate each period separately.
Is more frequent compounding better?+
Yes, but the difference is small. At 5%, annual vs. monthly is about 0.1 pp; daily is similar. Term and rate matter much more.
Does it factor inflation?+
Only nominal returns. For real returns, subtract inflation (e.g., 2โ3%/yr).