Calculator Inputs
Use the fields below to estimate future portfolio value and then remove inflation’s effect to see real purchasing power.
Formula Used
Gross Effective Return = (1 + Nominal Rate / Compounding Frequency)Compounding Frequency − 1
Net Periodic Rate = (Nominal Rate / Compounding Frequency) − (Fee Drag / Compounding Frequency) − (Tax Drag / Compounding Frequency)
Net Effective Return = (1 + Net Periodic Rate)Compounding Frequency − 1
Real Effective Return = [(1 + Net Effective Return) / (1 + Inflation Rate)] − 1
Real Balance = Nominal Balance / Cumulative Inflation Factor
The calculator simulates growth month by month. It adds scheduled contributions, applies the net investment return, compounds inflation, and then converts future dollars into today’s purchasing power.
Real contribution totals are also adjusted for inflation timing, helping you compare inflation-adjusted profit against the actual purchasing power of money added over time.
How to Use This Calculator
- Enter your starting portfolio amount.
- Add the amount you expect to contribute each year.
- Choose how many years you plan to invest.
- Set your expected nominal return before inflation.
- Enter expected inflation, annual fees, and tax drag.
- Select compounding and contribution timing assumptions.
- Click the calculate button to see nominal and real results.
- Review the graph and yearly table, then export if needed.
Example Data Table
Example assumptions: $20,000 initial investment, $4,800 annual contributions, 10 years, 8.5% nominal return, 3.1% inflation, 0.60% fee drag, 0.40% tax drag, monthly compounding, monthly end-of-period contributions.
| Year | Nominal Contributions | Real Contributions | Nominal Balance | Real Balance | Cumulative Inflation | Nominal Gain | Real Gain |
|---|---|---|---|---|---|---|---|
| 1 | $24,800.00 | $24,721.46 | $26,521.14 | $25,723.70 | 3.10% | $1,721.14 | $1,002.24 |
| 2 | $29,600.00 | $29,300.95 | $33,548.53 | $31,561.39 | 6.30% | $3,948.53 | $2,260.44 |
| 3 | $34,400.00 | $33,742.75 | $41,121.48 | $37,522.58 | 9.59% | $6,721.48 | $3,779.83 |
| 4 | $39,200.00 | $38,051.00 | $49,282.33 | $43,617.08 | 12.99% | $10,082.33 | $5,566.08 |
| 5 | $44,000.00 | $42,229.70 | $58,076.73 | $49,855.01 | 16.49% | $14,076.73 | $7,625.31 |
Frequently Asked Questions
1. What does inflation-adjusted return mean?
It measures growth after removing inflation’s effect. A portfolio may rise in dollars yet lose purchasing power. Real return shows what your future money can actually buy.
2. Why are nominal and real balances different?
Nominal balance is the raw future amount. Real balance discounts that amount by cumulative inflation, converting it into today’s money for a more realistic comparison.
3. What is tax drag in this calculator?
Tax drag is an estimated annual reduction in performance from taxes on dividends, interest, or realized gains. It helps model taxable accounts more conservatively.
4. Why include fee drag separately?
Management fees, advisory costs, and fund expenses reduce compounding over time. Separating fee drag makes it easier to test lower-cost or higher-cost investing scenarios.
5. Does contribution timing matter?
Yes. Money added earlier has more time to compound. Start-of-period contributions usually produce slightly higher ending values than end-of-period contributions.
6. Can I use this for retirement planning?
Yes. It is useful for long-term planning, retirement projections, and comparing savings strategies. Still, it remains a planning estimate, not a guaranteed forecast.
7. What inflation rate should I enter?
Use a long-run estimate that matches your planning horizon. Many investors test several values, such as base, optimistic, and conservative scenarios, to see the range of outcomes.
8. Is the real effective annual return the same as profit?
No. The real effective annual return is a rate. Real profit is the inflation-adjusted ending balance minus inflation-adjusted contributions made over the investment period.