Average Calculator
Find the average of any list with the sum, count and substitution shown line by line. Also called an average finder; the page reports the arithmetic mean and compares it with the median so a skew does not fool you.
- No upload
- Worked steps
- Free, no sign-up
100% Local in Browser — Your Data Never Leaves This Tab
Comma, space, tab or newline separated. Paste an Excel column directly; blank lines and labels are ignored.
Try a sample
Paste a dataset to begin
The worked steps, table, box plot and summary update as you type. Nothing is sent anywhere.
How it works
- 1
Paste the list
Paste grades, measurements, prices or an Excel column. The parser accepts commas, spaces, tabs and line breaks, and ignores blank cells so a stray row does not become a zero.
- 2
Divide the total
The average is Σx / n. The page shows the actual numerator and denominator, plus the sorted data, so the result can be checked by hand or copied into a lab report.
- 3
Read the right average
The Quick Summary compares the mean with the median. For income, house prices or a class with one very high score, the median is often the better description; the page gives you both without pretending they are interchangeable.
More tools
- Median CalculatorPaste a dataset and get the median with the sorted list, the exact middle position or pair, and a box plot. Odd and even counts are handled separately, and the numbers never leave your browser.
- Mean CalculatorAdd a list of numbers and see the mean with the sum, the count and every substitution in Σx / n. The dataset stays in your browser and carries over to the median, SD, IQR and z-score pages.
- Standard Deviation CalculatorGet sample or population SD with a row-by-row deviation table, the definition formula and the computational Σx² − n·x̄² formula. Copy the APA result or switch to population variance without re-pasting the data.
- Interquartile Range (IQR) CalculatorCompare Q1, Q2, Q3 and IQR under the TI-83/84/AP exclusive rule, Tukey’s inclusive hinges and Excel QUARTILE.INC interpolation. See the 1.5 × IQR fences, potential outliers and a live box plot.
- Z-Score CalculatorTurn x, μ and σ into a z-score and a left-tail, right-tail or two-tailed probability, or standardize every value in your dataset at once. The standard normal curve fills the same area the table reports.
What it won't do
- “Average” is ambiguous in everyday English. This page calculates the arithmetic mean; the median and mode are different summaries, and the Quick Summary surfaces the median explicitly.
- The result is only as good as the pasted list. Duplicate values are kept as duplicates, and a missing value is not imputed.
- A weighted average needs weights. Expand each value by its frequency or use the weighted formula separately; this page treats every pasted number as one observation.
- All parsing and calculation happen in the tab; there is no server request to inspect or delete.
Questions
How do you calculate an average?
Add the values and divide by how many there are. For 12, 15, 18, 20 and 22 the sum is 87 and n is 5, so the average is 17.4. The page prints that same substitution with your own numbers.
Is an average finder the same as a mean calculator?
In this tool, yes: both names describe the arithmetic mean. “Average” is the broader everyday word, so the page also shows the median and explains when the two summaries disagree.
Should I use the mean or the median?
Use the mean when every observation should contribute proportionally and the distribution is not badly skewed. Use the median when a few extreme values would dominate the result, such as home prices or one very high exam score.
Can the average be a number that is not in the list?
Yes. The mean is a calculated balance point, not necessarily an observed value. For 1, 2 and 9 the mean is 4, which is not in the dataset; the median is 2.
What happens to blank cells?
They are ignored rather than counted as zero. If a blank really means zero, type the zero explicitly; that is a modelling decision the calculator should not make silently.
Does this page upload my grades or prices?
No. The numbers are parsed in JavaScript and never sent to a server. The shared dataset lives in sessionStorage only so the other five pages can reuse it in the same tab.