4️⃣ Quartile Calculator
Calculate the first quartile, median, and third quartile using linear interpolation.
📊 Statistics📐 Formula included🧠 Practice questions✓ Free
Please enter valid values.
Formula and Explanation
Calculate the first quartile, median, and third quartile using linear interpolation.
| Concept | Formula or rule |
|---|---|
| Quartile Calculator | Q₁ = 25th percentile · Q₂ = median · Q₃ = 75th percentile |
How to Use This Calculator
- Enter the sample, counts, probabilities, or summary statistics requested above.
- Keep paired lists in the same order and separate values with commas.
- Select the correct test direction or sample/population option when available.
- Press Calculate and interpret the result together with the supporting statistics.
Worked Example
Example: For 1, 2, 3, 4, 5, the quartiles using linear interpolation are 2, 3, and 4.
✓ Q₁ = 2, Q₂ = 3, Q₃ = 4
Where This Is Used
School & coursework
Check homework, understand formulas, and verify step-by-step statistics exercises.
Research
Explore estimates, uncertainty, distributions, and relationships before using full statistical software.
Business & data analysis
Summarize variation, compare groups, and communicate data-driven findings clearly.
Common Mistakes to Avoid
⚠️
Assuming one universal method
Software packages may use different quartile conventions.
Software packages may use different quartile conventions.
⚠️
Not sorting data
Quartiles are based on ordered values.
Quartiles are based on ordered values.
⚠️
Confusing Q3 with the maximum
Q3 is the 75th percentile, not the largest value.
Q3 is the 75th percentile, not the largest value.
Practice Questions
1. Find Q2 for 2,4,6,8.
Answer: 5
2. What percentile is Q3?
Answer: 75th percentile.
3. Which quartile equals the median?
Answer: Q2.
Frequently Asked Questions
What percentage of data lies below Q1?▾
Approximately 25%.
Is Q2 always the median?▾
Yes.
Why might my textbook show slightly different quartiles?▾
It may use a median-of-halves method instead of interpolation.