Project portfolio value forward with regular contributions and a compound growth rate.
The starting balance and the contribution stream are compounded separately: the balance as a lump sum, the contributions as an ordinary annuity. The final-year growth line shows how heavily compounding is back-loaded. In a long projection most of the final value comes from returns rather than contributions, and almost all of that arrives in the last third of the period.
Portfolio Growth
Future value = start × (1+i)ⁿ + contribution × ((1+i)ⁿ − 1) ÷ i, with i the monthly rate
Future value = start × (1+i)ⁿ + contribution × ((1+i)ⁿ − 1) ÷ i, with i the monthly rate The starting balance and the contribution stream are compounded separately: the balance as a lump sum, the contributions as an ordinary annuity. The final-year growth line shows how heavily compounding is back-loaded.
In a long projection most of the final value comes from returns rather than contributions, and almost all of that arrives in the last third of the period.
This calculator takes 4 inputs: Starting portfolio value, Monthly contribution, Expected annual return, Years to project. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.