# Opportunity Cost Calculator

URL: https://speedycalculator.com/calculators/finance/opportunity-cost/
Last updated: 2026-10-25

> The opportunity cost calculator shows what spending money today really costs: how much it would grow to if invested instead – after tax on gains and adjusted for inflation.

## Inputs

- Money to spend
- Annual return on savings (%)
- Investment period (years, months)
- Tax on investment gains (%)
- Annual inflation rate (%)

## Results

- Value if invested (before tax)
- Total savings after tax
- Opportunity cost in today's money
- Real gain given up

## Formula

```
Future value = amount × (1 + return)^years
After-tax gain = (FV − amount) × (1 − tax rate)
Opportunity cost in today's money = (amount + after-tax gain) ÷ (1 + inflation)^years
```

## Explanation

Every purchase has a hidden cost: the investment return you give up. A $5,000 car upgrade could be worth $14,000 in 15 years at 7%. That doesn't mean you shouldn't spend – just that you should know the trade-off.

### How to use the Opportunity Cost Calculator

- **Money to spend**
- **Annual return on savings**
- **Investment period**
- **Tax on investment gains**
- **Annual inflation rate**

Results update as you type, and every field accepts the units shown in its menu.

### How it works

Enter the amount you are thinking of spending, the return you could earn, the period, the tax on gains and inflation.

### Tips

- Use the nominal annual rate and pick the compounding frequency your bank or broker states.
- Small differences in return or fees compound into large differences over decades.
- Run the calculation with a cautious, a central and an optimistic return to see the range of outcomes.
- Past returns do not guarantee future returns – nothing here is investment advice.

### Common mistakes to avoid

- Comparing an APR with an APY or effective rate.
- Ignoring inflation, taxes and fees when judging a real return.
- Entering a percentage as a decimal (5 instead of 0.05 is correct here).

### Inputs explained

FieldWhat to enterMoney to spendAmount in your currencyAnnual return on savingsIn %Investment periodUnits: years, monthsTax on investment gainsIn %Annual inflation rateIn %

### What each result means

- **Value if invested (before tax)** = [Money to spend]×(1 + [Annual return on savings]÷100)^[Investment period]
- **Total savings after tax** = [Money to spend] + ([Value if invested (before tax)] - [Money to spend])×(1 - [Tax on investment gains]÷100)
- **Opportunity cost in today's money** = [Total savings after tax]÷(1 + [Annual inflation rate]÷100)^[Investment period]
- **Real gain given up** = [Opportunity cost in today's money] - [Money to spend]

### Example values

How the main result changes when **Money to spend** changes and everything else stays at the example values above:

Money to spendTotal savings after tax2,5006,237.943,7509,356.915,00012,475.886,25015,594.867,50018,713.8310,00024,951.77

## Worked example

Inputs — Money to spend: $5,000; Annual return on savings: 7 %; Investment period: 15 years; Tax on investment gains: 15 %; Annual inflation rate: 2.5 %.

Results — Value if invested (before tax) = $13,795.16; **Total savings after tax = $12,475.88**; Opportunity cost in today's money = $8,614.17; Real gain given up = $3,614.17.

## FAQ

**What is opportunity cost?**
The value of the best alternative you give up when you make a choice.

**Should I invest instead of spending?**
Weigh the opportunity cost against the value the purchase brings you.

**Why adjust for inflation?**
So the future value is shown in today's purchasing power.

**What formula does the Opportunity Cost Calculator use?**
Future value = amount × (1 + return)^years.