Average Calculator
Paste numbers, plan a target, or combine group averages without losing their counts.
Find the arithmetic mean without hiding input mistakes
The arithmetic mean is sum ÷ count. Paste up to 1,000 plain decimal values; the calculator accepts punctuation or whitespace separators but does not silently ignore malformed tokens. A comma always means “next value,” so grouped thousands such as 1,000 are rejected as ambiguous. Write 1000 for one thousand or put separate values on different lines.
Compare mean and median
The mean uses every value and can move substantially when the list contains an extreme value. The median sorts the values numerically and takes the middle value; for an even count it averages the two middle values. This page shows both, along with the sum, count, minimum, and maximum, so the mean is not presented without context.
Plan the average needed across remaining items
The target planner treats every current and remaining item as equally weighted. It computes needed future total = target × (current count + remaining count) − current sum, then divides by the remaining count. The answer is the average needed across the remaining items—not a requirement that every item have the same value.
Minimum and maximum fields are visible, editable assumptions. They test whether a real-number aggregate average can fit inside that range. They do not solve integer-only scores, grading increments, caps that differ by item, unequal weights, or a unique item-by-item combination.
Combine averages using each group's count
Two or more group averages cannot usually be averaged directly. A group with 100 observations should contribute more than a group with 2. This tool reconstructs each implied total as group average × group count, adds the implied totals, and divides by the combined count. It also displays the naive mean of group means as a labeled wrong comparison when counts differ.
Because a source group average may already be rounded, the combined result inherits that uncertainty and is labeled approximate. The 2, 4, or 6 decimal setting changes display formatting only; internal calculations are not rounded first.
Frequently asked questions
How do I calculate an average?
Add the values, then divide the sum by the number of values. The default tool shows the arithmetic mean, sum, count, median, minimum, and maximum without changing the underlying values to match the display precision.
What separators can I paste?
Use commas, semicolons, spaces, tabs, or new lines between plain decimal values. A comma always separates values here; decimal commas and comma-formatted thousands are intentionally not guessed. Ambiguous input such as 1,000 is rejected.
How can I find the average needed to reach a target?
Enter your current equal-weight values, target final average, and remaining item count. The planner finds the total and average needed across all remaining items. Optional minimum and maximum assumptions check aggregate reachability, not a unique set of scores.
Can I combine two class or group averages?
Yes, if you also know each group's count. Multiply every group average by its count, add those implied totals, and divide by the total count. Directly averaging group averages is wrong when group sizes differ.
Why is the combined group result labeled approximate?
An entered group average may already be rounded. Weighting it by count carries that earlier rounding into the combined result, even though this calculator does not round intermediate arithmetic.
Is the mean always the best summary?
No. A very high or low value can pull the mean. Compare the median shown beside the mean and inspect the original data before treating one number as representative.