How this calculator works
- Step 1Begin with money today₹1,00,000.00The initial amount gets every period of growth.
- Step 2Add equal deposits₹10,000.00120 month-end deposits in the default illustration.
- Step 3Add their ending values₹20,51,424.38Every deposit grows only for the periods remaining after it arrives.
Future value combines cash contributed on different dates into an equivalent balance at one ending date. The starting amount gets the full duration. Later deposits have fewer periods to compound, so multiplying all contributions by the full growth factor would overstate the result.
The headline is a constant-rate illustration, not a forecast. It assumes every planned deposit arrives and that the entered rate applies throughout. It does not choose an investment or estimate a return from market data.
Worked example: starting money and monthly deposits
- Number of periods
N = years × payments per year- Starting amount grown
FVinitial = amount × (1 + i)^N- End-of-period deposits grown
FVpayments = payment × [(1 + i)^N − 1] ÷ i- Combined balance
FV = FVinitial + FVpayments
- irate per payment period 0.67%
- Nnumber of payment periods 120
- Starting amount₹1,00,000.00
- Each monthly deposit₹10,000.00
- Total cash contributed₹13,00,000.00
- Starting amount at the ending date₹2,21,964.02
- Regular deposits at the ending date₹18,29,460.35
- Compound gain under the assumption₹7,51,424.38
- Projected future value₹20,51,424.38
The nominal annual rate is divided by twelve in this monthly example. Periodic rates are not rounded before calculating. Displayed amounts are rounded to paise, while the downloadable timeline retains the underlying precision.
Move deposits earlier, not the ending date
- End-of-period deposits₹20,51,424.38The last deposit joins at the ending date and gets no growth.
- Start-of-period deposits₹20,63,620.78Every regular deposit gets one more period of rate exposure.
End timing places deposits at periods one through N. Start timing places them at zero through N minus one. Both contain the same number of deposits. The initial amount stays at period zero either way.
The start-of-period deposit component is the end-of-period component multiplied by one plus the periodic rate. With a positive rate this increases value. With a negative rate it decreases value because the money experiences an extra period of shrinkage.
Nominal and effective annual rates
- Nominal annual assumption₹20,51,424.38The full-year compound change is 8.3%.
- Effective annual assumption₹20,17,135.23The full-year compound change stays 8%.
A nominal rate divides by payments per year. An effective annual rate instead uses a periodic rate whose compoundings reproduce exactly the entered annual change. These conventions agree with annual payments, but generally differ with more frequent payments.
Frequency controls both deposit dates and compounding here. If you change from monthly to annual without changing the deposit amount, you also change total contributions. That is not a pure comparison of compounding frequency.
Zero growth and steady shrinkage
- Zero assumed growth₹13,00,000.00The ending value equals total contributions.
- Negative assumed growth₹7,97,024.61The ending balance is below contributed cash under steady shrinkage.
At zero rate, each deposit keeps its original value, so the annuity component is payment times payment count. The engine handles this directly instead of dividing by zero. Small nonzero rates use numerically stable factors.
Negative rates are allowed down to the stated input limit. They describe a fixed decline each period, not the path, volatility or sequence of actual market returns. A negative compound gain is a loss in this illustration, not a separate charge.
Read the balance on the right money basis
Future rupees are not today's purchasing power, and a projected gain is not a promise.
The starting-money and deposit components are both valued at the ending date. Total contributed is only the original cash put in; the difference is compound gain or loss. No taxes, fees, inflation adjustment or missed deposits are modelled.
Use the payment timeline to inspect when each deposit arrives and how much it contributes to the final amount. To work backwards from future receipts instead, use the Present Value Calculator.
Related time-value tools
Future value grows money forwards. Discounting back, or planning monthly investing, has its own tool.
To find today’s equivalent of future receipts, use the present value calculator. For monthly mutual fund investing with step-ups, try the SIP calculator, or the compound interest calculator for other compounding.
The inflation calculator shows what the ending amount buys today.
Common mistakes
Mistake: Grow the full contribution total for the whole duration.
Instead: Give each deposit only the periods left after it arrives.
Mistake: Treat a monthly deposit amount as an annual amount.
Instead: Match the entered amount to the selected frequency.
Mistake: Compare nominal and effective rates without checking their meaning.
Instead: Read the periodic and effective annual rates beneath the result.
Mistake: Expect a quoted bank maturity value from this general worksheet.
Instead: Check that product rules, dates, fees and rounding match before comparing.
Sources and independent checks
A period-by-period balance recurrence checks the closed-form compound calculation.
OpenStax supplies the compound-value and equal-payment framework. Independent tests add deposits and apply the periodic rate step by step, then compare the ending balance with the closed form. Further tests reconcile every timeline row, negative rates and inverse single-sum calculations.
Read how we test our calculators, or browse more money calculators.