Assumptions and method

When to be cautious

Inflation and nominal rate must use the same period and currency basis.

Real rate = (1 + nominal)/(1 + inflation) − 1

Test a scenario

Use your own inputs

Inputs stay in your browser. Shared scenario links include your inputs.

Use the result in a decision

Use consistent currency, timing and price assumptions.

Inflation and nominal rate must use the same period and currency basis.

Set a baseline and change one assumption to compare outcomes.

A worked example

Follow the fixed teaching example
  1. Convert percentages to fractions.
  2. Real rate = (1.08 ÷ 1.03 − 1) × 100 ≈ 4.8544%.

These illustrative inputs describe a project scenario, not a published benchmark. All monetary inputs use the same currency and price basis.

Nominal rate (%)
8
Inflation per period (%)
3
Real rate
4.8544 %

Interpret the output only within the assumptions above. Changing the inputs changes the result; it does not validate the inputs.

Source & credit

Standard financial mathematics; no single inventor is asserted.

OpenStax: Principles of Finance, capital budgeting

This is independently written code and explanation of the underlying method. The linked publication, its diagrams and its trademarks remain its owner’s material; no permission to reuse them is implied.

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