In Excel: right-click the series with the different scale, choose Format Data Series and tick Secondary Axis — or use Chart Design ▸ Change Chart Type ▸ Combo and tick Secondary Axis next to that series.
Build the chart with both series on it, even though one looks flat.
Click the flat series once to select it — if it is too small to hit, use Chart Design ▸ Select Data or the series dropdown on the Format tab.
Right-click ▸ Format Data Series ▸ Series Options ▸ Plot Series On ▸ Secondary Axis.
Open Chart Design ▸ Change Chart Type ▸ Combo and give the secondary series a different shape (usually Line) so the two are not mistaken for one scale.
Add an axis title on both sides stating the unit — a dual-axis chart without units is unreadable.
What this does
A secondary axis gives one series its own scale on the opposite side of the chart, so a small-magnitude series (a 4.2% conversion rate) stays visible next to a large-magnitude one (€480,000 of revenue). Without it the small series flattens into the baseline. Excel allows exactly one secondary axis per chart, and the Combo chart type is where you also choose a different shape — typically columns on the primary axis and a line on the secondary. The same idea underpins a lot of everyday Excel work, so the few minutes spent getting it right here pay back across every sheet you build afterwards. Treat it as a pattern, not a one-off, and it stops being something you look up and starts being something you reach for. For “make a excel chart with two y axis”, the reliable version is a short checking loop, not just the first command that appears to work. Run it on a deliberately small range first, watch how the affected chart change, and only then apply the same setup to the full sheet. When this is a ribbon command, the selection matters more than the button: confirm the range, apply the command, then spot-check the output before saving. That is what makes a visual that makes the number obvious at a glance useful in real work: repeatable, auditable, and not dependent on memory or luck.
A worked example
B2:B13 holds monthly revenue (€40k–€90k) and C2:C13 holds conversion rate (3%–6%). Plotted together, the conversion line sits flat on zero. Right-click the conversion series ▸ Format Data Series ▸ Secondary Axis, then Change Chart Type ▸ Combo and set Revenue to Clustered Column and Conversion Rate to Line. Both curves are now readable, with % on the right axis. A secondary axis is what lets a rate sit beside a volume in one picture — revenue against margin, sessions against conversion, output against defect rate. A practical tip before you scale it up: build it once on a small block of test data, confirm the number against the tool on this page, and only then point it at your real sheet. That one habit catches almost every mistake while it is still cheap to fix, long before a wrong figure reaches a report or a colleague.
In Google Sheets
Google Sheets handles this almost identically to Excel. The formula syntax above is the same, and the menu lives under a slightly different label rather than a ribbon tab. Use the platform toggle at the top of the page to switch every keyboard shortcut between Windows and Mac, and expect at most cosmetic differences in naming. The aim was to get you unstuck fast and leave you a little more capable than a copy-paste would. The answer is at the top, the tool proves it, and the detail above shows why it holds — so the next time a colleague asks, you can answer without reaching for search. The short version of “make a excel chart with two y axis”: the answer is at the top of this page, the tool proves it on your own numbers, and the sections above explain why it holds so the next variation does not stump you. Excel rewards people who reference cells instead of typing values and who keep inputs separate from formulas, because that is what makes a result you can audit months later. Build it once, deliberately, with the live tool as a check, and you convert a one-off lookup into a reusable skill — which is the whole point of learning the why and not just the what.
Common mistakes
- Leaving both series as columns, so readers compare bar heights that use two different scales.
- Starting one axis at zero and the other somewhere else, which lets you manufacture an apparent correlation.
- Adding a secondary axis when the real fix is a percentage or index of both series on one scale.
- Forgetting the unit on the right-hand axis, the single most common reason a dual-axis chart gets misread.
Frequently asked questions
How do I add a secondary axis in Excel?
Right-click the series that needs its own scale, choose Format Data Series, and under Series Options select Secondary Axis. On Mac the same option sits in the Format Data Series pane.
Can a chart have two y axes?
Yes — one primary and one secondary, so two scales in total. Excel does not support a third.
Why is my secondary series invisible?
It is usually hidden behind the primary series. Change its chart type to Line under Change Chart Type ▸ Combo, or reorder the series in Select Data.
Is a dual-axis chart a good idea?
Only when the two series genuinely use different units. If both are currency or both are counts, one axis is clearer and harder to misread.
Other ways people ask this
On the way here you may have searched this as “make axis start at 0 excel” and “how to make chart in excel with two y axis” — it is all the same task, and this page is the single, complete answer to it.
This guide also answers
- how to make a excel graph with two y axis
Why do people search for this in so many different ways?
Because the same task has many names. “make axis start at 0 excel”, “how to make chart in excel with two y axis” all point at the one operation explained on this page, which is why they all lead here.