In Excel: calculate compound interest with =P*(1+rate/n)^(n*years), where n is the number of compounding periods per year — or with =FV(rate/n, n*years, 0, -P) using the built-in future value function.
On this page7
Put principal, annual rate, years, and periods per year in four cells.
Compute =P*(1+rate/n)^(n*years) — or =FV(rate/n, n*years, 0, -P).
Note the minus sign on P in FV: Excel treats the deposit as money paid out.
Format the result as Currency and check the rate, term and compounding frequency in the formula.
What this does
Compound interest pays interest on previously earned interest, so a balance grows geometrically rather than linearly. The compounding frequency n matters: 5% compounded monthly yields slightly more than 5% compounded yearly, because each month's interest starts earning its own interest immediately. FV exists precisely for this; the explicit power formula shows what it is doing. Most people learn this as a sequence of clicks and forget it by next week; learning it as a pattern instead is what lets you apply it to the next, slightly different version of the problem without starting from scratch. That is the difference this page is trying to make. The difference between a quick fix and a sheet you can trust is the extra minute you spend validating “monthly compounding formula excel”. Start on a copy or a tiny sample, keep the affected formula visible, and compare the result with the outcome you expected before you touch the real workbook. When a formula is involved, keep the inputs labelled beside it, reference cells instead of typing values, and apply number formatting only after the result checks out. The point is a calculation you can defend to a CFO or an auditor, but the practical win is that someone else can open the file and understand what happened without asking you.
A worked example
With €10,000 at 5% compounded monthly for 10 years, =10000*(1+0.05/12)^(12*10) returns €16,470.09. Compounded only yearly, =10000*(1.05)^10 returns €16,288.95 — the extra €181 is the compounding-frequency effect. The equivalent built-in is =FV(0.05/12, 120, 0, -10000). Savings plans, loans, and investment projections all run on compound growth. Setting the formula up once with cell references lets you test scenarios by typing. Check the referenced cells, argument order and result type in your workbook. Start with the worked example before changing an input, then compare the changed result with the calculation you expected. An error value or a result of a different type is a reason to inspect the inputs and arguments.
In Google Sheets
Google Sheets support for this task has not been verified. Check the function, arguments and workflow in the target product before transferring the example. Matching formula notation does not establish identical behaviour. Nothing on this page is behind a login or a download: the exact answer is at the top, and the detail below it is there for when you need it. That is the whole promise here — the answer first, and just enough context to make it stick. For “monthly compounding formula excel”, keep the input cells and the result visible while you check the formula in Excel. Follow the worked example and change one input at a time. The steps explain the workbook calculation; this page does not run a live calculator for that task.
Common mistakes
- Using the annual rate per month without dividing by 12.
- Forgetting the minus sign on the present value in
FVand getting a negative result. - Comparing offers with different compounding frequencies by nominal rate alone — use
=EFFECT(rate, n)to get the effective annual rate. - Entering 5 instead of 0.05 (or 5%) for the rate, which explodes the result.
Frequently asked questions
What is the compound interest formula in Excel?
There is no COMPOUND function; use =P*(1+rate/n)^(n*years) or =FV(rate/n, n*years, 0, -P).
What does compounding frequency change?
How often interest is added to the balance. More frequent compounding yields a higher effective annual rate for the same nominal rate.
How do I add monthly deposits?
Use the pmt argument of FV: =FV(rate/12, months, -deposit, -P) for end-of-month deposits.