Your files stay on your device Simple interest calculator Compute simple interest and total repayable in days, months, or years, or back-solve the missing rate, time, or principal. Enter a principal, a rate, and a time. Simple interest is the flat kind: principal times rate times time, charged once, never snowballing. The day-count basis only matters for day-based terms, and the banker's 360 is a convention that quietly pays a little more interest than actual/365 on the same deal. The comparison line compounds the same principal yearly at the same rate so you can see the gap; most real loans compound monthly, which drifts higher still. What it does not do: fees, penalties, part-period payments, amortisation schedules, or tax. Back-solving assumes the given interest is plain simple interest, not a compounded figure. Options More unit & math tools - Unit converter (/converters/units) - Average and median (/converters/statistics) - Fraction calculator (/converters/fractions) All unit & math tools (/converters) Was this tool useful? YesNo Canonical HTML: https://nutter.tools/converters/simple-interest-calculator Markdown version: https://nutter.tools/converters/simple-interest-calculator.md Plain-text version: https://nutter.tools/converters/simple-interest-calculator.txt Agent index: https://nutter.tools/llms.txt