Investment Horizon Planner

Your investment horizon depends on growth, contributions, withdrawals, and your target goals. This tool simulates your portfolio year by year.

1. Portfolio evolution

Starting balance:
B_0

Annual contribution:
C

Annual withdrawal:
W

Net annual return (decimal):
r

For year t (1..N):
B_t = (B_{t−1} + C − W) × (1 + r)
        

Contributions and withdrawals are applied before growth each year.

2. Horizon to depletion

If goal type = "How long portfolio lasts":

Simulate years until:
B_t ≤ 0
or
t reaches max years
        

The horizon is the number of years until the portfolio is exhausted or the simulation limit is reached.

3. Horizon to target value

If goal type = "Years to reach target value":

Target value:
T

Simulate years until:
B_t ≥ T
or
t reaches max years
        

The horizon is the first year your balance meets or exceeds the target value.

Thinking in horizons helps you align risk, withdrawals, and goals. Shorter horizons usually call for more conservative assumptions; longer horizons can tolerate more volatility but require discipline.

Worked example

Suppose you have $500,000, expect 5% annual returns, contribute $10,000 per year, and withdraw $25,000 per year in retirement. You can model:

• How many years the portfolio can sustain those withdrawals.
• How the ending balance changes if you adjust contributions or withdrawals.

Using the results

If the horizon is shorter than you’d like, you can explore lower withdrawals, higher contributions, or different return assumptions. If you’re modeling a target value, you can see how long it might take to reach a savings goal under different scenarios.