Part of a whole
100% stacked area chart
Shows changing component shares by normalising each time point to 100%.
- Chart
- Composition
- Trend over time
What it answers
How do shares evolve independently of totals?
- Shape
- Stacked bands of constant total height
- What it shows
- Share gains and losses.
Example
The question
How has the share of orders by channel shifted through the year?
Share of orders by channel, 2025
Illustrative data. It belongs to no company.
When to use it
Use it when
Changing composition across many periods.
Avoid it when
When absolute quantities or changes in total are required.
How to read it
Read each vertical slice as 100% and compare band thicknesses.
Note
Each time point needs a positive total.
The data you need
- Layout
- Long table
- Fields
- Time: date/datetime; Series: text; Value: number
- One row is
- One series observation at one time. What is the grain?
- Rules
- Sort time within series. Resolve duplicate time-series pairs and align series before stacking.
- Optional
- Wide alternative: Time,A,B with one row per time.
- Preparation
- Align series, sum each time slice, then divide each component by that slice total.
- Units
- Each time slice totals 100%; denominator is the sum of included component values at that time.
Worked example
Data Jan: A30, B45; Feb: A34, B40. Convert to shares. A rises 40% to 45.9%; this alone does not show total growth.
| Time | Series | Value |
|---|---|---|
| 2026-01-01 | A | 30 |
| 2026-01-01 | B | 45 |
| 2026-02-01 | A | 34 |
| 2026-02-01 | B | 40 |