Starlight Tools

Mean, Median, Mode, Range Calculator

Paste homework data, spreadsheet columns, or mixed-delimiter number lists to get mean, median, mode, range, quartiles, IQR, possible outliers, and visible calculation steps.

Numbers & Actions

Results

Results will appear here after calculation.

Tip: Ctrl/Cmd + Enter runs Calculate.

Formulas Used

Mean = sum of values / nAverage of all detected numbers.
Median odd n = middle valueSort the data, then pick the center value.
Median even n = (middle left + middle right) / 2Average the two center values.
Mode = value(s) with highest frequencyReports all tied modes; no mode when all values occur once.
Range = max - minDifference between the largest and smallest values.
Q1, Q3 = medians of selected halvesUses the quartile method selected in the tool.
IQR = Q3 - Q1Spread of the middle 50% of the dataset.
Fences = Q1 - 1.5 x IQR, Q3 + 1.5 x IQRValues outside the fences are flagged as possible outliers.

Quartile method: Exclusive median-of-halves excludes the overall median from Q1 and Q3 when the count is odd. Inclusive median-of-halves includes it. Textbooks and software can vary, so switch methods if you need to match a class or worksheet.

Acceptable Input Formats

Format Example
Comma-separated4, 7, 9, 10
Spaces or new lines4 7 9 10 or one value per line
Semicolons and mixed delimiters4; 7, 9 10
Negatives and decimals-2.5, 0, 4.75
Scientific notation1e3, 2.5e-2, -4E+1

Mean, Median, Mode, and Range Help

This calculator summarizes a dataset in seconds and shows the arithmetic behind each answer. It is built for homework checks, spreadsheet cleanup, test scores, measurements, prices, survey responses, and any list where you need the average, middle value, most common value, and spread.

What these statistics mean

The mean is the familiar average: add all values and divide by the count. Because every value contributes, a few very large or very small numbers can pull the mean up or down. The median is the middle value after sorting the list, so it is more stable when there are outliers. The mode is the most frequent value; some datasets have multiple modes, and others have none if every value appears only once. Together, these measures of central tendency show where the “center” of your data lies.

To understand spread, the calculator also shows the range (max minus min) and the quartiles. Quartiles split your ordered data into four equal parts, and the interquartile range (IQR) captures the middle 50%. The IQR is especially helpful when you want a robust sense of variability without being overly influenced by extreme values. The outlier check uses the common 1.5 x IQR rule, which flags values below Q1 - 1.5 x IQR or above Q3 + 1.5 x IQR.

How to use the calculator

  1. Enter your numbers separated by commas, spaces, semicolons, or new lines.
  2. Choose decimal places and the quartile method you need to match.
  3. Click Calculate (or press Ctrl/Cmd + Enter) to see the results.
  4. Review the answer cards, parsed-input summary, and worked steps for mean, median, mode, range, quartiles, IQR, and outliers.

Example presets

Use the preset buttons to compare a simple homework list, repeated values with more than one mode, and a skewed dataset that includes an outlier. Each preset fills the input and calculates immediately so you can see how the interpretation changes.

Calculation method and review

Maintained by Starlight Robotics for Starlight Tools. Last reviewed: July 7, 2026. The calculator uses standard descriptive statistics definitions for mean, median, mode, range, quartiles, IQR, and Tukey-style 1.5 x IQR outlier fences. All calculations run locally in your browser, so your data stays private.

Frequently Asked Questions

Which separators can I use?

Commas, spaces, semicolons, or new lines. Extra whitespace is ignored.

What is the difference between mean and median?

The mean adds every value and divides by the count. The median is the middle value after sorting, so it is less affected by a few very high or very low numbers.

When should I use median instead of mean?

Use the median when the data is skewed or has outliers, such as income, home prices, or response times.

Can there be more than one mode?

Yes. If two or more values tie for the highest frequency, the calculator lists every mode.

How do outliers affect the mean and range?

Outliers can pull the mean toward the extreme value. They can also make the range much larger because range only compares the minimum and maximum.

How are quartiles and IQR computed?

We sort your numbers, split the dataset using the selected quartile method, calculate Q1 and Q3 as medians of those halves, then calculate IQR = Q3 - Q1.

Why does my quartile result differ from Excel?

Quartile methods vary. This calculator offers exclusive and inclusive median-of-halves methods. Excel and other tools may use inclusive, exclusive, or percentile interpolation formulas.

Can I paste data from a spreadsheet?

Yes. Paste rows or columns directly. The calculator accepts commas, spaces, semicolons, new lines, negatives, decimals, and scientific notation, then reports any ignored tokens.

What if there is no mode?

If every value appears once, there is no mode and we’ll say so.

Is my data private?

Yes—calculations run entirely in your browser.

5 Fun Facts about Mean, Median & Mode

One outlier can drag the mean

Add a single giant value (say, a billionaire’s income) and the mean leaps upward—even if every other number stays small.

Outlier power

Medians are traffic reporters

Highway speed signs often show the median speed, not the mean—because medians ignore a few reckless drivers or slow trucks.

Robust pick

Modes work on words

Mode isn’t just numeric: the most common baby name, T-shirt size, or hex color in a pixel array is a mode, too.

Beyond numbers

IQR defines “box plot” whiskers

Classic box plots flag outliers at 1.5×IQR beyond Q1 or Q3—the middle 50% is literally the box.

Visual stats

Simpson’s paradox flips stories

Combine groups and a mean or median trend can reverse direction—always check subgroups before trusting a headline.

Group caution

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