Three ways to describe the center
The arithmetic mean is the sum divided by the number of observations. The median is the middle sorted value; with an even count, average the two middle values. Modes are the values tied for the highest repeated frequency.
This calculator reports no mode when every value appears once. If several repeated values tie for the highest frequency, it reports all of them. Range is the maximum minus the minimum; it measures spread rather than center.
Example: 7, 3, 9, 3, 12, 8, 3, 15, 9
The sorted values are 3, 3, 3, 7, 8, 9, 9, 12, 15. Their sum is 69 and their count is 9, so the mean is 69 ÷ 9 ≈ 7.666667. The fifth value gives a median of 8. The mode is 3, appearing three times, and the range is 15 − 3 = 12.
Choosing a useful summary
A large outlier can pull the mean away from typical observations. The median is less sensitive to extreme values; the mode can show a repeated measurement or common category code, but numeric codes still need context.
Enter up to 10,000 numbers with magnitudes at most 10⁵⁰. Commas separate observations, not thousands: enter 1000 instead of 1,000 for a single value. Every token must be numeric. One value is enough for center and range, but sample standard deviation needs at least two.