Calculate the arithmetic mean of a list

The list is split on new lines or semicolons. A single value is allowed (the mean is then that value). Empty lines are skipped. For credits or volumes as weights, use the weighted-average page.

x̄ = (x₁ + x₂ + … + xₙ) / n

US (12.5) and continental (12,5) decimals are both read. The mean is not a median or a mode: an outlier pulls x̄ toward itself. No trimming, no winsorizing.

Values

At least one valid number. Lines that are not numbers are ignored if anything valid remains; an empty list is rejected.

Assumptions

• Equal weight per observation.
• You want the arithmetic mean, not a geometric or harmonic mean.

Limits

• No median, mode, or standard deviation.
• A typo of 1000 among 10s dominates the mean.

20 is the balance point of 10, 20, and 30. If 10 is a quiz worth 10% and 30 is a final worth 50%, this equal-weight mean is the wrong tool — use weights.

• Averaging already-averaged subgroup means without weights.

  If groups have different sizes, use the weighted-average calculator with size as the weight.

• Treating the mean as a typical value when the list is skewed.

  The mean follows the tail. This page does not compute a median.

• Weighted averageEach line is a value and its coefficient. The mean is the sum of (value × weight) divided by the sum of weights — not the average of the values then of the weights.
• PercentageEnter two numbers of the same kind. The tool returns (part ÷ total) × 100 — useful for a test score, a slice of a budget, or a share of a count.

Written by Rédaction HexaCalc (editorial team). Content last updated: August 25, 2026. No third-party medical or financial review is claimed.

This calculation uses a standard mathematical identity. See also the methodology.