'Average' usually means the mean — but the median and mode tell different stories about the same data. Here is how to compute all three.
The mean (the everyday average)
Mean = Sum of all values ÷ Number of values
For 4, 8, 15, 16, 23, 42:
- Add the values: 4 + 8 + 15 + 16 + 23 + 42 = 108
- Count them: 6 values
- Divide: 108 ÷ 6 = 18
The median (the middle value)
Sort the data and take the middle entry:
- Odd count — the middle value. For 3, 9, 11 → median = 9
- Even count — the average of the two middle values. For 4, 8, 15, 16, 23, 42 → (15 + 16) ÷ 2 = 15.5
The mode (the most frequent value)
The value that appears most often. For 2, 3, 3, 5, 7, 3 → mode = 3. Datasets can have no mode, one mode, or several.
Which one should you use?
- Mean — best for symmetric data without outliers; used in GPAs and per-km rates.
- Median — better when data is skewed. Median household income beats mean income because a few billionaires pull the mean up.
- Mode — best for categories: most common shoe size, most popular answer.
Outlier example — test scores 70, 72, 74, 76, 20:
- Mean = 62.4 (dragged down by the 20)
- Median = 72 (represents the class better)
Put it into practice
Paste any list of numbers into the free Mean, Median & Mode Calculator to get all three (plus the sum and count) instantly. To see how spread out your data is, follow up with the Standard Deviation Calculator.
