Periodic Investment Calculator
For a regular monthly investment plan and total contributions.
Estimate future value from an initial amount and monthly investments.
These calculators share some inputs, but each answers a different financial question.
For one amount where interest is not added back to principal.
Open calculatorFor growth of one principal amount with reinvested returns.
Open calculatorFor a general investment projection with additional contributions.
Open calculatorFor a regular monthly investment plan and total contributions.
The periodic investment calculator projects a mathematical future value for an initial investment plus regular monthly contributions under a constant annual return assumption. It also shows total contributions, projected gain and the number of modeled months.
Enter the initial investment, monthly contribution, assumed annual return and investment period in years. The calculator converts the annual return to a monthly rate, rounds years × 12 to a whole number of months, compounds the initial amount monthly and models monthly contributions as end-of-period contributions.
Initial and monthly investments cannot be negative, years must be greater than zero and annual return cannot be below −100%. The entered annual return is a constant mathematical assumption converted to a monthly rate. The model does not simulate volatility, changing returns, fees, taxes or inflation.
With initial investment 10,000, monthly contribution 1,000, annual return 7% and 10 years, the engine models 120 months. Total contributions are 130,000, projected future value is 193,181.42 and modeled gain is 63,181.42.
This is a deterministic growth scenario, not a forecast or investment recommendation. Compare multiple return assumptions and include real-world costs and risk separately.
No. It is an assumption used for the projection. Real investment returns vary and can be negative.
The implemented future-value formula treats regular monthly contributions as end-of-period contributions.
No. Unless reflected indirectly in the return assumption you enter, they are not separately modeled.
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