The comparison at a glance
| Interval | Frequency | Cumulative count | Cumulative share |
|---|---|---|---|
| [0, 2) | 2 | 2 | 25% |
| [2, 4) | 3 | 5 | 62.5% |
| [4, 6] | 3 | 8 | 100% |
Build an exact-value tally first
For the fictional list 1, 1, 2, 2, 2, 4, 5, 5, the exact frequencies are 1→2, 2→3, 4→1 and 5→2. They sum to eight observations. This table answers which exact value is most common: 2 occurs three times. The sum of the displayed value labels would not answer that question.
Group the same observations explicitly
Using intervals [0, 2), [2, 4) and [4, 6] gives frequencies 2, 3 and 3. The two observations at 1 enter the first interval, the three observations at 2 enter the second, and 4, 5, 5 enter the last. The final interval includes its upper endpoint, although no value equals 6 here.
Add a cumulative column only when order means something
The grouped cumulative counts are 2, 5 and 8. Dividing by eight gives cumulative shares of 25%, 62.5% and 100%. These describe observations below successive boundaries under the stated closure rule. For unordered categories, a cumulative count depends on the chosen order and needs a clear reason, as in a descending Pareto ranking.
Use the table to check the chart
A histogram should reproduce the grouped frequencies exactly. Check that their total matches N and that every boundary observation is assigned once. A frequency table is already a summary: importing its frequency column as raw observations would change the meaning. The maker below expects individual values and generates the grouped table for you.
A related chart you can inspect
References and reproducibility
The worked arithmetic and teaching examples on this page are original. Background reading: NIST histogram background. Source code and reuse terms expose the implemented calculations.
Written by SupaMakers for ChartsAI · September 8, 2026.