waterfall() — Waterfall chart

Shows ups and downs adding up to a final total.

waterfall(values)

Key idea

• A waterfall chart shows how a starting value changes step by step into a final value. (e.g. 100 + 40 - 25 = 115)
• Rising steps add to the running total (the amount so far); falling steps subtract. (e.g. +40 up, -25 down)
• Each bar starts where the previous one ended, so they float instead of sitting on zero.
• It makes the contribution of each gain or loss clear. (e.g. revenue +40, costs -25)
• Great for breaking a net change (the overall result) into its parts. (e.g. start 100, end 115)

Definition

$$\text{end}=\text{start}+\sum _i{\Delta }_i$$

$\text{start}$

the opening value

${\Delta }_i$

each step up (+) or down (-)

$\text{end}$

the final running total

In plain words

Like steps going up and down, where you see exactly what added to the total and what took away from it.

Where you'd use it

• Start with revenue $100k, subtract costs $40k and taxes $15k. A waterfall shows each drop as a falling bar, landing on a final profit bar of $45k, so you see exactly what ate into the total.
• Explain a bank balance over a month: open at $2000, add a $3000 paycheck, subtract $1200 rent and $800 spending, ending around $3000 — each step floats from where the last ended.
• Show headcount change: start at 50, add 8 hires, lose 3 leavers, finishing at 55, with green rises and red falls making the net change obvious.

Frequently asked questions

What is a waterfall chart for?

Showing how a starting value grows and shrinks through a sequence of changes to a final total.