Averages & Means

Average Calculator

Find the exact arithmetic mean of a list of signed decimal values.

Averages & Means

Enter values to average

Exact arithmetic mean
  1. 1EnterProvide the known values
  2. 2CalculateResults update automatically
  3. 3VerifyReview the details and units
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Values

Use ordinary decimals; blank rows are ignored.

Exact average

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Understand the subject

What is an arithmetic average?

An arithmetic average, or arithmetic mean, replaces several values with one equal-share value while preserving their total. It answers: “If the total were shared equally among all observations, how much would each receive?”

Use it for quantities that can sensibly be added—such as scores, measurements, costs, or daily counts. Every entered value contributes equally.

The relationship

Average formula

xᵢ is each value, Σxᵢ is their total, n is the number of values, and is the mean.

See the idea

The mean is a balance point

The left side totals 40. Moving 6 units from 16 fills the 4-unit and 2-unit gaps below 10, making four equal groups of 10. Nothing is created or lost.

Worked example

Average of 6, 8, 10, and 16

Add the four values, then divide by the number of values.

x̄ = (6 + 8 + 10 + 16) ÷ 4 = 40 ÷ 4 = 10

Interpret with care

When an average can hide information

The mean uses every value, so one extreme value can pull it away from where most observations lie. It also says nothing about spread: two datasets can share the same mean and look very different. For a fuller distribution summary, use the Mean, Median & Mode Calculator.

Quick guide

How to use this calculator

  1. Add one signed value per labelled row.
  2. Read the reduced exact result and its decimal representation.
  3. Use the displayed exact sum to verify the calculation.

Calculation method

Add, then divide by the count

The arithmetic mean is the exact sum of all values divided by the number of values. Finite decimals are converted to rational numbers before any operation.

Worked example

Average of 4, 7, and 10

Their sum is 21 and there are three values.

(4 + 7 + 10) / 3 = 7

Supported inputs

Precision and limits

List size

Add 1–100 labelled value rows.

Decimal size

Each value may contain up to 200 digits and 100 decimal places.

Exactness

Exact rational results are never replaced by a rounded decimal; approximations are labelled.