How this calculator works
The annual return is effective and converted into an equivalent monthly rate for a recurring plan. Monthly contributions arrive at period end; only completed months create deposits. Reverse modes find an opening amount, monthly contribution or constant annual return. Time-to-target mode returns the first whole month reaching the target for a monthly plan, or a fractional year for a lump sum. Returns, fees, taxes and distributions must be reflected consistently in your assumed rate.
Formula
Monthly i = (1+a)^(1/12)-1. For complete monthly periods N, F = P(1+i)^N + C[(1+i)^N-1]/i. A partial final month grows the existing balance without adding a partial deposit.
Worked example
A $1,000 lump sum at 10% effective annual return reaches $1,210 after two years. With zero return, twelve $100 monthly contributions and no opening balance produce $1,200.
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Frequently asked questions
Is the annual return nominal or effective?
It is an effective annual assumption. Twelve equivalent monthly growth factors reproduce that annual return.
Does this include fund fees or account charges?
Only if you incorporate them into the return assumption. Use the investment fee calculator to model charges separately.
Is the projected return guaranteed?
No. This is a constant-rate scenario. Mutual fund prices and account rates can change, and an investment fund is different from an insured deposit account.