Waterfall encodes values as signed bar height from a running total. Popularised in 1980s–90s consulting decks (McKinsey waterfall).
In reports, ads and assignments it fits P&L bridges, budget vs actual, headcount walks. Skip it when the story is a trend over many periods, not a bridge.
Rules
- Rules 1 — Use signed bar height from a running total as one channel, not two.
- Rules 2 — Direct labels beat a distant legend.
- Rules 3 — Do not hide zero. If you break the axis, say so.
- Rules 4 — Colour encodes category or magnitude, not both.
- Rules 5 — Put the claim in the title, not just “Waterfall”.
- Rules 6 — Source and period, even in small type.
Palette
- Palette 1 — Categories: distinct hues. Sequences: one hue, changing value.
- Palette 2 — Diverging: a neutral centre, emphasis at both ends.
- Palette 3 — One brand colour plus greys beats a rainbow.
- Palette 4 — Check contrast on a projector and in greyscale print.
Type
- Type 1 — Tabular figures for numbers. Do not pour body copy into the chart.
- Type 2 — Titles as sentences; axes as short nouns.
- Type 3 — For CJK, drop weight one step and leave tracking.
Waterfall: honour signed bar height from a running total, and switch when the story is a trend over many periods, not a bridge.