calculator
Compound Interest Calculator
Compare standard nominal annual-rate compounding with a fixed rate applied every calendar day or weekday, without tax, fee, inflation, product, or investment-advice assumptions.
Estimate how a starting amount changes with standard annual-rate compounding or with a fixed percentage applied to each eligible day.
Result
How it works
Choose Nominal annual rate for the standard nominal annual-rate compound-interest formula, where the annual rate is divided by the selected frequency. Choose Daily rate for a separate fixed daily-rate scenario that applies the full entered percentage once per eligible day. Every calendar day includes weekends; Weekdays only excludes Saturdays and Sundays but not public holidays or market closures. Results use high-precision arithmetic and may use scientific notation for extremely large values. This is deterministic math for planning and learning, not investment advice or a guaranteed return; it excludes taxes, fees, inflation, changing rates, and product rules.
Examples
Monthly compounding
Input: 1000 at 5% for 10 years, compounded monthly
Output: 1647.01 final amount
Yearly compounding
Input: 5000 at 4% for 5 years, compounded yearly
Output: 6083.26 final amount
Quarterly compounding
Input: 2500 at 3.5% for 8 years, compounded quarterly
Output: 3302.12 final amount
Daily compounding
Input: 1200 at 6% for 3 years, compounded daily
Output: 1437.92 final amount
Fixed daily rate
Input: 1000 growing 3% per day for 365 calendar days
Output: 48482724.53 final amount
Zero rate
Input: 2500 at 0% for 8 years
Output: 2500 final amount and 0 interest earned
Zero years
Input: 750 at 6% for 0 years
Output: 750 final amount before time passes
Effective rate check
Input: 1000 at 5% compounded monthly
Output: 5.11619% effective annual rate
FAQ
Is this investment advice?
No. This is an arithmetic calculator for compound-interest math, not investment advice, product selection, tax guidance, or a guaranteed return.
What formula does it use?
It uses principal multiplied by one plus the periodic rate, raised to the number of compound periods.
What is effective annual rate?
Effective annual rate shows the annualized effect of compounding when the nominal annual rate is split into multiple periods.
Does it include recurring deposits?
No. Version 1 only compounds the starting principal. Recurring deposits or withdrawals need contribution-timing rules that are intentionally out of scope.
Does it include tax, fees, or inflation?
No. The result excludes taxes, fees, inflation, changing rates, penalties, spreads, and account-specific rules.
Can the interest rate be zero?
Yes. A zero rate keeps the final amount equal to the principal and returns zero arithmetic interest earned.
Can I use daily compounding?
Yes. In annual mode, Daily splits the nominal annual rate into 365 periods. In daily-rate mode, the full entered rate is applied once per eligible day. These are very different calculations.
Does weekdays only exclude public holidays?
No. Weekdays only removes Saturdays and Sundays. It does not use a country-specific holiday list, exchange calendar, or market-closure schedule.
What should I check before relying on the result?
Check the source rate, compounding rule, taxes, fees, product terms, risk, and official documents before making a financial decision.