Question 1

How does compound inflation work?

Accepted Answer

Each year prices grow by the rate × previous price. At 3% annually, $100 → $103 → $106.09 → $109.27 … not $100 → $103 → $106. After 30 years at 3% inflation, $100 needs $242.73 to maintain the same purchasing power.

Question 2

What inflation rate should I use?

Accepted Answer

Long-term US CPI averages ~2.5-3.5%. Germany/Euro area ~2%. UK ~3%. For long-term planning, 3% is a safe assumption. For real recent data, look up your country's official CPI.

Question 3

Is anything uploaded?

Accepted Answer

No. All math runs in your browser.

Region	~Recent avg	Notes
US (1990-2024)	2.8%	Higher in 2021-2023, calmer otherwise
Eurozone	2.0%	ECB target, mostly held until 2022
UK	2.5-3%	BoE target 2%, often above
Japan	~0.5%	Decades of near-zero, recent uptick
Turkey	15-50%+	Persistent high inflation

Inflation Calculator

Forward vs backward

Long-term inflation reference (annualised)

The compound effect

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