Loans and interest: pick the method first
For the same principal, rate, and term, your monthly payment and total interest depend on the repayment method. Comparing the two most common:
| Equal payment (annuity) | Equal principal | |
|---|---|---|
| Monthly payment | Same every month | Decreases over time |
| Early burden | Relatively low | Highest |
| Total interest | More | Less |
Example: $100,000 at 5% for 30 years — equal payment stays around $537/month, while equal principal starts near $690 and falls. Choose equal payment for a steady amount, equal principal to save on total interest.
Compound interest: time is everything
In savings and investing, compound interest means "interest earning interest," so longer horizons matter most. Try changing the principal, rate, and contribution interval to see how the maturity value shifts.
Calculated in your browser
The amounts and rates you enter are never sent to a server. For the repayment methods in detail, see the loan repayment calculator guide.