Free calculator
Inflation calculator
See how a flat annual inflation assumption changes purchasing power over time. Pick forward (grow today’s amount into the future) or backward (express today’s amount in older dollars). We show an equivalent amount, cumulative inflation over the horizon, and a simple break-even nominal return line—transparent math for Sheets or Excel, not a government CPI database.
When to use this calculator
Quick assumption checks before you paste the same exponent into a larger workbook.
- Stress-test a constant inflation line against a savings or salary story you explain elsewhere.
- Translate “today’s $” into past dollar amounts for a memo or chart footnote.
- Copy POWER / caret patterns into Google Sheets or Excel so reviewers see the same definition as this page.
- Jump to the compound interest or retirement savings calculators when you need contributions, returns, and optional “today’s dollars” in one timeline.
This page uses one constant annual rate π (as a decimal internally) and a horizon t in years. It is a classroom-style shortcut, not a replay of published monthly CPI paths.
Forward (multiply)
Equivalent = amount × (1+π)^t. Cumulative inflation = (1+π)^t − 1, reported as a percent.
Backward (divide)
Equivalent = amount ÷ (1+π)^t—today’s cash expressed in nominal units of t years ago under the same π.
What we do not model
Official price indexes, seasonal adjustment, salary tax and payroll rules, hyperinflation safeguards beyond π > −100, and real interest beyond a single FAQ pointer—use dedicated products when you need them.
For past prices brought up to today, the same multiply applies: treat the old price as amount, pick forward, and set t to years since that quote. For balances with deposits and return, open the compound interest calculator; for optional “today’s dollars” on a nest egg, see the retirement savings calculator. The TVM calculatordiscounts your cash flows at your rate—it is not a CPI inflation engine.
Google Sheets & Excel
A1 = amount, B1 = annual inflation as a percent (e.g. 3), C1 = horizon in years (can be a decimal). Names follow US/UK English packs; use Insert function for other language packs.
=A1*POWER(1+B1/100,C1)Same as amount × (1+π)^t with π = B1/100.
=A1/POWER(1+B1/100,C1)Expresses today’s A1 in nominal terms t years earlier at rate B1.
Frequently asked questions
What does this inflation calculator do?
It applies a constant annual inflation percent you supply over a horizon you choose, then shows an equivalent amount, cumulative inflation, and a simple break-even nominal return line—illustration math for planning conversations.
What formulas do you use?
Forward: amount × (1+π)^t. Backward: amount ÷ (1+π)^t with π as a decimal per year (percent ÷ 100). Cumulative inflation = (1+π)^t − 1.
When should I pick Forward vs Backward?
Forward grows an anchor into later nominal dollars (future purchasing power at π). Backward takes today’s amount and expresses it in earlier nominal dollars. Past prices brought to today also use the multiply path—use Forward with the historic figure as amount.
I have an old price tag—how do I get “today’s dollars”?
Enter that historic amount, choose Forward, set t to the years since the tag, and use an inflation assumption that matches your story. This is not the same as loading official CPI factors unless you type the implied average π yourself.
Is this the same as the BLS CPI inflation calculator?
No. Government calculators apply published index levels between calendar dates. We never load those series here—use BLS, Minneapolis Fed, Destatis, Bundesbank, Insee, or national statistics offices when you need index-backed answers.
Is this the same as the TVM calculator’s discount rate?
No. TVM uses your nominal discount or loan rate on cash flows. Inflation here is only the purchasing-power shortcut π on a single amount—do not swap the two without a deliberate story.
How does this relate to the retirement calculator’s inflation field?
The retirement tool’s optional inflation line deflates a future nest egg with (1+π)^t for a “today’s dollars” read—same family of math, different UI and questions. Use retirement for contributions and ages; use this page for pure inflation on one amount.
Can inflation be negative?
Yes—small negative π models deflation while 1+π stays positive. Extreme inputs are not guarded beyond π > −100; treat answers as illustrations.
Do you support monthly inflation instead of annual?
v1 is annual compounding of π only. For monthly steps you can convert an effective annual assumption or build a schedule in your sheet.
What is the “break-even nominal return”?
A rough reminder: a nominal investment return near π (before tax and fees) offsets inflation in this simplified story—it is not a product promise.
Where is the real interest rate (Fisher)?
We do not ship a Fisher panel here. For (1+nominal)/(1+inflation)−1 style teaching, combine this page’s π with the compound interest or TVM tools and keep labels explicit in your workbook.
How do I match this in Google Sheets or Excel?
Use the copy cards: =A1*POWER(1+B1/100,C1) and =A1/POWER(1+B1/100,C1). In German Excel you may need ; instead of , between arguments.
Is this investment or macro advice?
No. It is a free educational tool—not a forecast, not tax or legal guidance, and not a substitute for qualified professionals when stakes are high.