ToolForage.
INVESTING CALCULATOR

Investment Growth Calculator

Model how an initial investment and annual contributions could change under a constant return, then translate the future amount into today’s purchasing power.

Calculator

%
years
Advanced options
%
YOUR RESULTS
Projected future value92,371.54
Total contributions
30,000.00
Modeled gain
62,371.54
Value in today’s money
56,371.66
Return on contributions
207.91 %

The model applies one constant return each year and discounts the final amount by the selected inflation rate.

Modeled investment value

Amounts use the same currency as your inputs.

Projected valueTotal contributions
046.2K92.4K135791214161820Year

Year 20

Deposits
30,000.00
Gain
62,371.54
Value
92,371.54

Each point shows a year-end value.

Annual growth summary
Annual growth summary
YearDepositsGainValue
111,000.00800.0011,800.00
212,000.001,744.0013,744.00
313,000.002,843.5215,843.52
414,000.004,111.0018,111.00
515,000.005,559.8820,559.88
616,000.007,204.6723,204.67
717,000.009,061.0526,061.05
818,000.0011,145.9329,145.93
919,000.0013,477.6032,477.60
1020,000.0016,075.8136,075.81
1121,000.0018,961.8839,961.88
1222,000.0022,158.8344,158.83
1323,000.0025,691.5348,691.53
1424,000.0029,586.8653,586.86
1525,000.0033,873.8158,873.81
1626,000.0038,583.7164,583.71
1727,000.0043,750.4170,750.41
1828,000.0049,410.4477,410.44
1929,000.0055,603.2784,603.27
2030,000.0062,371.5492,371.54

Understanding your result

Future value combines deposits and modeled growth. Inflation-adjusted value divides the result by cumulative inflation, offering a purchasing-power comparison.

To annualize growth between two values with no intervening contributions, use the CAGR Calculator rather than treating contributed cash as investment gain.

The formula

Next value = (prior value + start contribution) × (1 + return) + end contribution

Contribution timing changes how long new money participates in growth. Returns can be negative but cannot be −100% or lower in this model.

Worked example

Starting with 10,000, adding 1,000 at each year-end, and earning 10% gives 14,200 after two years. With 2% inflation, that equals about 13,648.60 in today’s money.

How to use this calculator

  1. Enter the initial investment, the contribution made each year, and the number of whole years.
  2. Set an annual return scenario; in the additional options, choose contribution timing and the annual inflation assumption.
  3. Compare future value with total contributions and value in today’s money, then inspect the annual balances.

Nominal and real value

A larger future number can buy less if prices rise. The inflation-adjusted result estimates present purchasing power, not a guaranteed price index outcome.

Keep nominal return and inflation assumptions internally consistent.

Sequence risk is hidden

A constant rate creates a smooth line, while actual markets rise and fall. With contributions or withdrawals, the order of returns can affect the ending value.

Use several return scenarios rather than treating one rate as a forecast.

Assumptions & limitations

What this calculation assumes

  • One return and inflation rate each year.
  • Fixed annual contribution.
  • No taxes, fees, or withdrawals.

What to keep in mind

  • Market volatility is not modeled.
  • Return on contributions is not a time-weighted performance measure.
  • Inflation varies by person and period.

Common questions

What is inflation-adjusted value?

It expresses the future amount in approximate today-money purchasing power.

Why does start timing produce more?

That contribution participates in one more annual return period.

Can annual return be negative?

Yes, above −100%, for loss scenarios.

Sources & further reading