Quick guide
How to use this calculator
- Enter two finite non-negative values.
- Inspect the starting arithmetic and geometric bounds.
- Read their common converged limit and iteration count.
Calculation method
Replace both values repeatedly
At each step, the larger arithmetic mean decreases while the smaller geometric mean increases. They converge rapidly to the arithmetic–geometric mean.
Worked example
AGM of 1 and 2
Starting at 1.5 and √2, repeated averaging converges near 1.45679.
aₙ₊₁=(aₙ+gₙ)/2; gₙ₊₁=√(aₙgₙ)
Supported inputs
Precision and limits
Domain
Both values must be finite and non-negative.
Convergence
Iteration stops when the two floating-point bounds agree within a scale-relative tolerance, with a 100-step safety cap.
