Combo Charts in Data Studio: Bars and Lines on Two Axes Without Confusing Anyone

• Only combine related measures
• Label both axes clearly
• Start the bar axis at zero
• Limit to two series
• Say what to look for

Combo charts, usually bars for volume and a line for a rate, are useful and easy to get wrong. I’m Harsh Khubchandani, an independent Data Studio consultant in New Delhi, and these are the rules I follow in Data Studio (formerly Looker Studio).

§Only combine related measures

Spend as bars and cost per lead as a line works, because the reader wants to see both together. Two unrelated metrics on two axes invite people to see a relationship that isn’t there.

§Label both axes clearly

When a chart has a right-hand axis, I make sure both axes show titles and units. A reader should never have to guess whether the line is in rupees or percent.

§Start the bar axis at zero

Bars encode size by length, so a bar axis that doesn’t start at zero exaggerates differences. Lines are more forgiving, but I still check the range isn’t hiding or inventing movement.

§Limit to two series

One bar series and one line is the sweet spot. Beyond that, I split into two charts stacked vertically with the same date axis, which reads more clearly than a crowded combo.

§Say what to look for

A one-line note above the chart, such as “spend up, cost per lead flat”, tells busy readers why the chart is there.

If your charts need a second look, I offer a free 30-minute review. Details at datastudioconsultant.com.