How to Calculate Compound Interest in Google Sheets Using the FV Function

Forecasting savings growth, retirement portfolio balances, and loan accumulations requires calculating compound interest over multi-year horizons. While building manual math formulas involves raising periodic interest rates to compounding exponential powers, Google Sheets features a powerful built-in financial function designed specifically for this purpose: the FV (Future Value) function. Using FV enables you to calculate compound growth for single lump-sum investments as well as ongoing periodic contribution plans.

Syntax and Parameters of the FV Function

The FV function computes the future valuation of an investment based on constant periodic payments and a fixed interest rate. Its syntax contains five arguments:

=FV(rate, number_of_periods, payment_amount, [present_value], [end_or_beginning])

• rate: The interest rate per compounding period (for instance, annual rate divided by 12 for monthly compounding).
• number_of_periods: The total number of payment or compounding intervals across the investment lifespan.
• payment_amount: The additional contribution deposited during each individual period (enter 0 for lump-sum calculations without recurring deposits).
• present_value (optional): The initial lump-sum principal invested at the beginning of the timeline.
• end_or_beginning (optional): Enter 0 if deposits occur at the end of each period (default), or 1 if contributions are made at the beginning of each interval.

Calculating Compound Growth on a Lump-Sum Investment

To calculate the future balance of an initial deposit compounding annually without additional recurring contributions:

1. Open Google Sheets and enter your baseline variables into separate cells:
   • A1 (Annual Rate): 7% (or 0.07)
   • A2 (Years): 10
   • A3 (Initial Deposit): 10000
2. Select cell A4 where the final compound return will appear.
3. Enter the following formula and press Enter:

   =FV(A1, A2, 0, -A3)

4. Google Sheets outputs $19,671.51.

Note on Financial Sign Convention: In financial accounting formulas, cash outflows (money deposited into an account) are represented as negative numbers (-A3), which ensures the returning future value displays as a positive cash asset.

Calculating Compound Interest with Monthly Deposits

Most real-world savings strategies involve an initial principal combined with monthly automated deposits. When compounding occurs monthly, you must adjust both the interest rate and the period count to reflect monthly intervals:

1. Enter your parameters into the sheet:
   • B1 (Annual Interest Rate): 6%
   • B2 (Investment Years): 5
   • B3 (Monthly Contribution): 250
   • B4 (Starting Principal): 5000
2. In cell B5, type the monthly-adjusted FV formula:

   =FV(B1/12, B2*12, -B3, -B4)

3. Press Enter. Google Sheets calculates $23,733.25.

Extracting Total Earned Interest

To determine the exact dollar amount generated solely by compounding interest (excluding your out-of-pocket deposits), subtract your cumulative contributions from the future value:

=B5 - (B4 + (B3 * B2 * 12))

This formula isolates the purely compounding returns earned over the duration of the investment plan.