Decile Calculator
Calculate deciles to divide your dataset into 10 equal parts for statistical analysis
Calculate Deciles
You can enter up to 1000 values. At least 9 values are required to calculate deciles.
What are Deciles?
Deciles divide a dataset into 10 equal parts
Each decile represents 10% of the data distribution
D1 = 10th percentile, D2 = 20th percentile, etc.
D5 (5th decile) equals the median
Useful for ranking and performance analysis
Decile Formula
Dk = [k × (n + 1) / 10]th data point
Dk: k-th decile
k: Decile number (1, 2, 3, ..., 9)
n: Total number of data points
Note: If the position is not a whole number, interpolation is used between adjacent values.
Common Applications
Academic grading and ranking
Income distribution analysis
Performance evaluation
Market research and analysis
Quality control in manufacturing
Medical reference ranges
Understanding Deciles in Statistical Analysis
What are Deciles?
Deciles are statistical measures that divide a dataset into 10 equal parts, each representing 10% of the data distribution. They are part of a broader family of quantiles that include quartiles (4 parts) and percentiles (100 parts).
How to Interpret Deciles
- •D1 (1st decile): 10% of values are below this point
- •D5 (5th decile): Equal to the median; 50% of values are below
- •D9 (9th decile): 90% of values are below this point
Calculation Method
Step 1: Sort the Data
Arrange all values in ascending order from smallest to largest.
Step 2: Apply the Formula
For each k (1 to 9): Position = k × (n + 1) / 10
Step 3: Interpolate if Needed
If position is not a whole number, interpolate between adjacent values.
Example Interpretation
If you have test scores and the 8th decile (D8) is 85, this means that 80% of students scored 85 or below, and only 20% scored above 85. This makes deciles particularly useful for understanding relative performance and creating percentile-based rankings.