What This Inflation Scenario Means
The calculator compounds the annual rate you enter over the selected horizon. A positive rate raises the modeled future price level, 0% leaves it unchanged, and a negative rate models deflation.
This is a constant-rate scenario, not a forecast of future CPI or any particular price. Real inflation varies over time and different goods, services and households can experience different price changes.
Inflation calculations are scenarios about purchasing power, not forecasts of what prices will actually do. A constant 3% assumption is useful because it lets you see the compounding effect clearly, even though real inflation moves from year to year. Negative inflation can also be modeled as long as the rate remains mathematically valid. If you are planning decades ahead, try more than one inflation assumption; the difference between them can become substantial over long periods.
Frequently Asked Questions
Can I enter 0% inflation?
Yes. At 0%, the modeled future cost and purchasing power remain unchanged.
Can the calculator model deflation?
Yes. Enter a negative annual rate greater than -100%. The model then compounds the assumed decline in the price level.
Why does a constant inflation assumption matter more over many years?
Each year's price level becomes the base for the next year's change. A small annual difference therefore compounds over time, just as an investment return does.
Methodology & Related Tools
Review how RatioCalc builds, tests and updates calculator models before using an estimate for a material decision.
Accuracy review
Conversion & Other family audit: .
Site-wide consistency review: September 4, 2026.