Compute simple interest — interest that stays constant because it is always calculated on the original principal. Enter the principal, annual rate and time in years to get the interest, the total amount, and the per-year breakdown.
The formula is I = P × r × t. For example, $10,000 at 5% for 3 years earns $500 per year, $1,500 total. Compare with compound interest, where each period's interest joins the principal.
Frequently asked questions
Simple vs compound interest — which pays more?
Compound, for any term longer than one period. Simple interest stays flat; compound grows on itself.
Can time be a fraction of a year?
Yes — 0.5 means six months, and interest is prorated linearly.
What uses simple interest?
Short-term instruments and some loans and bonds; car loans are typically simple interest.
中文说明
计算单利——因为永远按原始本金计息，每期利息保持不变。输入本金、年利率与年数，即可得到利息、本息总额与逐年明细。
公式为 I = P × r × t。例如本金 10000、年利率 5%、存 3 年，每年利息 500，共 1500。可与复利对比——复利中每期利息会并入本金。
常见问题
单利和复利哪个收益高？
只要期限超过一期，复利必然更高。单利每期固定，复利利滚利。
时间可以填小数吗？
可以，0.5 表示半年，利息按时间线性折算。
哪些场景用单利？
短期工具、部分贷款和债券；车贷通常是单利。