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Investment Growth Calculator

Calculate how your investments grow over time with compound returns and inflation-adjusted projections.

Your Investment

Market Assumptions

Results
Nominal
￥9,175,630
Before inflation adjustment
Real (Inflation-Adjusted)
￥7,527,213
Purchasing power in today's yen
Total Contributions
￥7,000,000
Total Interest Earned
￥2,175,630
Inflation reduces purchasing power by 18% over 10 years

Inflation Sensitivity

See how different inflation rates affect your purchasing power

If inflation were 0%
￥9,175,630
No inflation impact
At current 2%
￥7,527,213
Your scenario
If inflation were 3%
￥6,827,530
Higher inflation scenario

Yearly Breakdown

YearNominal ValueReal ValueContributionsInterest
11,650,0001,617,647600,00050,000
22,332,5002,241,926600,000132,500
33,049,1252,873,259600,000249,125
43,801,5813,512,073600,000401,581
54,591,6604,158,808600,000591,660
65,421,2434,813,909600,000821,243
76,292,3055,477,831600,0001,092,305
87,206,9216,151,037600,0001,406,921
98,167,2676,834,004600,0001,767,267
109,175,6307,527,213600,0002,175,630

How It Works

This calculator projects the future value of your investments using compound returns, then adjusts for inflation to show the real purchasing power.

Nominal Future Value
FV = P × (1 + r)t + PMT × [ (1 + r)t − 1 ] / r
  • P — Initial investment
  • r — Expected annual return (as a decimal)
  • t — Investment period (years)
  • PMT — Annual contribution (monthly × 12)
Real (Inflation-Adjusted) Value
Real FV = Nominal FV / (1 + inflation)t

The real value shows what your future money is worth in today's purchasing power after accounting for inflation.

Example

If you invest ¥1,000,000 and add ¥50,000/month for 20 years at 6%: nominal value is ¥23.3M, but after 2% inflation it's worth ¥15.7M in today's money. Inflation cuts ~33% of the purchasing power.

This calculator runs entirely in your browser. No data is sent to any server.

Disclaimer

This is for informational and educational purposes only. Past performance does not guarantee future results.

Investment Growth Calculator: Guide

Intent
Project investment growth with inflation-adjusted real returns. See both nominal and real (inflation-adjusted) future values side by side.
What it does
Calculates nominal and inflation-adjusted (real) future values of an investment with monthly contributions, showing both side by side.
Key features
Nominal value projection, Inflation-adjusted real value, Yearly breakdown table, Contributions vs growth breakdown
Privacy
Everything runs locally in your browser. No data is uploaded.
Best for
  • Understanding the real purchasing power of future savings after inflation
  • Planning retirement with realistic inflation-adjusted projections
  • Comparing nominal returns vs actual spending power
Why this tool
  • Shows nominal and real values side by side for clear comparison
  • Yearly breakdown helps visualize the impact of inflation over time
  • Local-only: no sensitive data uploads

How to use

  1. 1Enter your initial investment and monthly contribution.
  2. 2Set your expected annual return rate and expected inflation rate.
  3. 3Choose your investment period in years.
  4. 4Review the nominal vs real value comparison and yearly table.

Common mistakes

  • Inflation rates are historical averages; actual future inflation will vary.
  • Expected returns are not guaranteed; past performance does not predict future results.
  • This calculator does not include taxes, fees, or trading costs.

Examples

30-year retirement planning
Initial: ¥3,000,000 Monthly: ¥50,000 Return: 6% Inflation: 2% Years: 30 Nominal: ~¥56.2M Real: ~¥31.0M
Short-term inflation check
Initial: ¥1,000,000 Monthly: ¥10,000 Return: 4% Inflation: 2% Years: 5 Nominal: ~¥1.9M Real: ~¥1.7M

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