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Calculation Methodology
This page documents how CAGRCalculator.tools performs its calculations so results can be checked independently.
Standard CAGR formula
The standard calculator uses beginning value (BV), ending value (EV), and elapsed time in years (n).
Reverse calculations
Future Value = Starting Value × (1 + CAGR)^n
Starting Value = Future Value ÷ (1 + CAGR)^n
n = ln(Future Value ÷ Starting Value) ÷ ln(1 + CAGR)
Time-period convention
Manual duration inputs use years + months ÷ 12 + days ÷ 365. Exact-date mode uses ACT/365 Fixed: actual elapsed calendar days divided by 365.
Precision and validation
Calculations use double-precision floating point without intermediate display rounding. Invalid zero periods, non-finite values, and undefined reverse calculations are rejected.
What CAGR does not measure
CAGR does not measure volatility, drawdowns, risk, fees, taxes, inflation, or intermediate cash-flow timing. IRR or XIRR may fit a cash-flow question better.