How much interest could your savings earn in a week? Or how much could borrowing cost you? Enter your starting amount, annual interest rate and number of weeks to calculate weekly interest in both money and percentage terms.
Weekly Interest Calculator
Calculate how much interest you earn or pay per week.
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- Total interest
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- Principal + interest
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Amounts use the same currency as your input.
How the Weekly Interest Calculator Works
The calculator turns an annual interest rate into a weekly estimate. Start by entering your principal amount: the money you have saved, invested or borrowed. Then enter the annual interest rate as a percentage and choose how many weeks you want to calculate.
Your results show the weekly interest amount, the weekly percentage rate, total interest over your selected period, and the principal plus interest. All amounts use the same currency as your input, so you can calculate in dollars, pounds, euros or another currency.
Choose Between Simple and Compound Interest
The simple interest option divides your annual rate by 52. For example, an amount of 10,000 at an annual rate of 5% produces approximately 9.62 in interest per week. The weekly rate is approximately 0.0962%. With this method, interest is calculated only on your original amount.
If you have an effective annual rate, such as APY or AER, select the effective annual rate option. This calculates an equivalent weekly rate and assumes interest compounds weekly. The weekly amount displayed is the first week’s interest. Later weeks earn slightly more because previous interest remains in the balance.
What Can You Use It For?
You can use the calculator to estimate interest on savings, explore different balances or understand the interest cost of borrowing. It is also useful when you want to compare several annual rates over the same number of weeks.
For example, try your current savings balance, then increase the amount to see how additional savings could affect your weekly interest. Alternatively, keep the balance unchanged and compare two rates to see the difference in money terms.
Why Calculate Interest Weekly?
Annual percentages can feel abstract. Converting them into weekly amounts makes the figures easier to relate to your everyday budget.
A weekly calculation also helps you assess whether a rate difference is meaningful for your balance. A higher rate may sound attractive, but the extra interest could be small over a short period. Seeing the actual amount gives you a clearer basis for comparison.
What Interest Rate Should You Expect?
Available rates vary by country, currency, provider and product. Easy-access savings, fixed-term deposits and loans can have very different rates and conditions. Use the rate quoted for your specific account or agreement, and check whether it is a simple annual rate or an effective annual rate.
Understanding the Estimate
The calculator uses 52 equal periods per year. It excludes fees, taxes, repayments and changes to your balance. Actual interest may differ when providers calculate it daily or apply another compounding schedule.