How do the methods differ?
- Annuity: principal plus interest is the same every month, which makes budgeting easy.
- Equal principal: you repay the same principal each month, so interest falls over time. Early payments are higher, but total interest is lower than with an annuity.
- Bullet: you pay only interest during the term and repay the whole principal in the last month. Total interest is the highest.
Interest is calculated each month as remaining principal × (annual rate ÷ 12) and rounded to the nearest won. Real loans can differ by a few won to a few hundred won because lenders use different day counts and rounding.
Frequently asked questions
Q. Does it work for variable-rate loans?
This calculator assumes the rate stays the same for the whole term. For a variable rate, recalculate whenever the rate changes.
Q. What about a grace period?
During a grace period you usually pay interest only. Add loan amount × annual rate ÷ 12 × grace months separately.
Q. Are early repayment fees included?
No. Check the fee rate in your loan agreement or with your lender.