Compound Growth Calculator
From initial principal, annual rate, years, frequency and contributions, compute the future value and total compounded growth.
Input Data
Results
At a glance:FV = PV x (1 + r/m)^(m·t) + PMT x ((1 + r/m)^(m·t) - 1) / (r/m); total principal = PV + PMT x m·t; growth = FV - principal. It handles both a lump sum and a recurring contribution (ordinary annuity, paid at period end). Example: 100k + 2k/mo at 6% monthly, 20y → FV ≈ 1.26m, growth ≈ 675k. WARNING: Fixed assumed return; real returns vary, not guaranteed; inflation and fees reduce real result. Education, not advice.
Formula
FV = PV × (1 + r/m)^(m·t) + PMT × ((1 + r/m)^(m·t) − 1) ÷ (r/m).
Total principal = PV + PMT × m·t; growth = FV − total principal.
$$$FV = PV\\left(1+\\dfrac{r}{m}\\right)^{mt} + PMT\\cdot\\dfrac{\\left(1+\\frac{r}{m}\\right)^{mt}-1}{r/m}$$$$$$Growth = FV - Principal$$$How to Use
- Enter the initial principal, annual rate and years.
- Pick the compounding frequency (e.g. monthly).
- Enter any periodic contribution to see FV, total principal and growth.
FAQ
What is the difference between compound and simple growth?
Compound growth reinvests each period's return so later returns earn on earlier returns ('interest on interest'); simple growth is on the original principal only. Over time, compounding accumulates far more.
Does a higher frequency always help?
At the same nominal rate, more frequent compounding gives a slightly higher FV, but with diminishing returns — annual to monthly is noticeable, monthly to daily is tiny.
When is the contribution paid?
This tool assumes an ordinary annuity — contribution at the end of each period. An annuity-due (paid at the start) would give a slightly higher FV.
What rate is realistic, and is the return stable?
There is no standard answer — it depends on asset class and risk. Conservative deposits/funds are low; equities/funds are higher but volatile. Use a long-term average and lean conservative; never treat the smooth fixed-rate result as a guarantee. Also factor inflation, fees (fund/management, trading) and tax. Run optimistic/neutral/conservative scenarios.
How do frequency and contribution timing affect the result?
Both matter, but less than amount, rate and time. Frequency: more frequent compounding lifts FV modestly (diminishing). Timing: start-of-period contributions earn one extra period versus end-of-period, so annuity-due FV is slightly higher. The dominant drivers of long-term results remain contribution, rate and time.
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References
Content review: Calculatorism Finance Team. Results are for reference only; please refer to the relevant authorities for the official figures.