Average Calculator
Calculate mean, median, mode, range, standard deviation, quartiles, and outliers. Three modes: descriptive statistics, weighted average, and frequency table.
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How It Works
Enter numbers separated by commas or spaces. The calculator computes: count, sum, mean, median, mode (flags "No mode" if all values are unique), min, max, range, midrange, population SD, sample SD, population variance, sample variance, Q1, Q2, Q3, IQR, skewness, kurtosis, CV%, and outliers using the Tukey 1.5×IQR fence. A histogram also renders for visual distribution.
Mean = Σx / n | SD = √(Σ(x−mean)² / (n−1)) | IQR = Q3 − Q1Input: 4,8,15,16,23,42 → Mean=18, Median=15.5, SD=14.08Each value gets a weight. Weighted mean = Σ(value × weight) / Σ(weights). Weights do not need to sum to 1 or 100 — the calculator normalizes automatically. Enter grade 90 weight 3, grade 80 weight 1: weighted mean = (90×3 + 80×1) / 4 = 350/4 = 87.5. Unweighted mean of 90 and 80 would be 85 — the difference shows the impact of weighting.
Weighted mean = Σ(xᵢ × wᵢ) / Σ(wᵢ)Physics 85 (4cr), Math 90 (3cr), History 78 (2cr) → WA = 85.1Enter each unique value and its frequency count instead of listing every individual value. Example: a class where 5 students scored 70, 12 scored 80, 8 scored 90. Enter value 70 frequency 5, value 80 frequency 12, value 90 frequency 8. The calculator computes the mean and full stats as if all 25 individual scores were entered.
Mean = Σ(value × frequency) / Σ(frequencies)70×5 + 80×12 + 90×8 = 2090 / 25 = 83.6The calculator flags outliers using the Tukey method: lower fence = Q1 − 1.5×IQR, upper fence = Q3 + 1.5×IQR. Any value outside these fences is listed as an outlier. Example: dataset 2, 3, 4, 5, 6, 100 — value 100 is an outlier (far above the upper fence). Outliers are listed in the results so you can decide whether to investigate or exclude them.
Outlier if: x < Q1 − 1.5×IQR or x > Q3 + 1.5×IQRData: 2,3,4,5,6,100 → outlier detected: 100Skewness measures distribution asymmetry: positive = right tail longer (mean > median), negative = left tail longer. Kurtosis measures peak sharpness vs a normal distribution: excess kurtosis > 0 means heavier tails (leptokurtic), < 0 means lighter tails (platykurtic). Both use sample-corrected formulas (n ≥ 3 required for meaningful results).
Skewness: γ₁ = n/((n−1)(n−2)) × Σ((xᵢ−x̄)/s)³Right-skewed income data: positive skewness, mean > medianQuick Reference
Common calculations — verify these in the calculator above.
Descriptive
Mean of 4,8,15,16,23,42
18
Descriptive
Median of 1,2,2,3,100
2
Descriptive
Mode of 1,2,2,3,3,3
3
Sample SD
SD of 2,4,4,4,5,5,7,9
2
Weighted
WA: 90(w=3), 80(w=1)
87.5
Quartiles
IQR of 1,2,3,4,5,6,7
3
Descriptive
Range of 5,10,15,20,25
20
Descriptive
Mean of 100,100,100,200
125
Tips & Shortcuts
Paste a column directly from Excel or Google Sheets — the calculator handles newline-separated values the same as comma-separated ones. No reformatting needed.
For weighted GPA, use credit hours as weights. The result automatically accounts for 4-credit courses having more influence than 1-credit courses.
If mean and median differ significantly, check the outlier list — a single extreme value can pull the mean far from where most data sits.
The Coefficient of Variation (CV%) in the results lets you compare spread across datasets with different units or scales. CV = SD / mean × 100.
For frequency table data, enter totals instead of individual values: "score 85, count 12" is faster than listing 85 twelve times and gives identical results.
Common Mistakes
Using mean for skewed data like income or house prices
A few billionaires in a dataset raise the mean dramatically while the median stays near the typical person. Always use median for right-skewed distributions. The calculator shows both — compare them to detect skew.
Using population SD when the data is a sample
Sample SD (divides by n−1) is almost always correct. Population SD (divides by n) is only valid when you have every possible value in the universe of interest — rare in practice. The calculator shows both; use sample SD by default.
Expecting mode to always exist
If all values appear exactly once, there is no mode. The calculator correctly reports "No mode" in this case. A dataset can also be bimodal (two modes) or multimodal — all are listed.
Confusing standard deviation with range as a measure of spread
Range = max − min and is sensitive to a single extreme value. Standard deviation uses all data points and is a more robust measure of typical spread. IQR (Q3−Q1) is even more robust, ignoring the top and bottom 25% entirely.
Entering numbers with units or symbols (e.g. $50, 30%)
Remove units before entering. The calculator accepts only numbers — entering "$50" causes a parse error. Strip dollar signs, percent signs, and commas from thousand separators (use 1000 not 1,000).
Frequently Asked Questions
Average (arithmetic mean) = sum of all values ÷ count. For 4, 8, 15, 16, 23, 42: sum = 108, count = 6, mean = 108 ÷ 6 = 18. This calculator also shows median, mode, standard deviation, quartiles, and outliers — all from the same input.
Mean: arithmetic average — sensitive to outliers. Median: middle value when sorted — resistant to outliers. Mode: most frequent value — can have multiple modes or none. For 1, 2, 2, 3, 100: mean = 21.6 (pulled up by 100), median = 2 (unaffected), mode = 2. Use median when data is skewed.
Weighted average = Σ(value × weight) / Σ(weights). Enter each value and assign it a weight. Example: GPA with 3 courses: Physics 85 (4 credits), Math 90 (3 credits), History 78 (2 credits). Weighted GPA = (85×4 + 90×3 + 78×2) / (4+3+2) = (340+270+156)/9 = 766/9 ≈ 85.1.
Standard deviation measures the average distance from the mean. Sample SD (divides by n−1): use when your data is a sample from a larger population — this corrects for bias. Population SD (divides by n): use only when you have every value in the entire population. In practice, sample SD is almost always the right choice.
Q1 (25th percentile) and Q3 (75th percentile) divide the sorted data into quarters. IQR = Q3 − Q1 covers the middle 50% of values. Outlier fences: lower = Q1 − 1.5×IQR, upper = Q3 + 1.5×IQR. Values outside these fences are flagged as outliers by the Tukey method, which this calculator uses automatically.
Use mean for symmetric data without extreme outliers (heights, test scores in a class). Use median for skewed data or when outliers exist (income, house prices, response times). A useful rule: if the mean and median differ by more than 10%, the data is skewed enough that median is the better summary statistic.
Separate numbers with commas, spaces, or new lines — all work interchangeably. Examples: "10, 20, 30" or "10 20 30" or paste a column from a spreadsheet. Negatives (−5) and decimals (3.14) are supported. The Frequency Table tab accepts values with repetition counts for large grouped datasets.
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