Hong Life CalculatorsUnderstanding the ROAS calculator — concept and principle
Return on ad spend (ROAS) tells you how much revenue your advertising brought in for every unit of money you put into it. Marketers use it to compare campaigns, channels and ad groups, to set bid targets in ad platforms, and to decide where the next budget should go. The calculator works with any currency, because ROAS is a ratio and the currency cancels out.
How it is calculated
ROAS = revenue attributed to ads ÷ ad spend.
- Revenue from ads is the sales value your tracking attributes to the campaign over a period.
- Ad spend is what you paid the ad platform over the same period.
The calculator shows the same number three ways: as a multiple (4×), as a percentage (400%) and as revenue per 1 spent (4). Ad platforms often express a target ROAS as a percentage, so 400% and 4× mean exactly the same thing.
The principle
ROAS is a simple efficiency ratio: output (revenue) divided by input (spend). Because both sides are measured in money, the result is unitless and can be compared across campaigns of very different sizes. Its main assumption is that the revenue figure is caused by the ads. In practice it depends on the attribution model (last click, data-driven, view-through) and the conversion window, so the same campaign can show different ROAS in different tools.
Worked example
- Revenue from ads = 12,000 USD, ad spend = 3,000 USD.
- ROAS = 12,000 ÷ 3,000 = 4.
- As a percentage: 4 × 100 = 400%.
- Result: ROAS 4×, meaning 4 USD of revenue for every 1 USD of ad spend.
How to read the result
ROAS measures revenue, not profit. Whether 4× is good depends on your margin. A useful benchmark is break-even ROAS = 1 ÷ gross margin. With a 25% margin you need at least 4× just to cover product cost and ads; with a 50% margin, 2× breaks even. Below 1× you are getting back less revenue than you spend. Compare ROAS over the same period, attribution model and conversion window, and look at the trend rather than a single day.
Common mistakes
- Treating ROAS as profit. A 4× ROAS can still lose money if margins are thin.
- Mixing periods: spend from one month, revenue from another.
- Ignoring returns, discounts and cancelled orders in revenue.
- Leaving out agency fees or creative costs when you want a full-cost view.
Frequently asked questions
What is the difference between ROAS and ROI?
ROAS divides revenue by ad spend. ROI divides profit (revenue minus all costs, including product cost) by the investment, so ROI is usually much lower and can be negative even when ROAS is above 1.
What is a good ROAS?
There is no universal number. Work out your break-even ROAS from your gross margin (1 ÷ margin) and aim above it with room for overheads.
Can ROAS be below 100%?
Yes. A ROAS of 0.8× (80%) means you earned 0.80 in revenue for each 1 spent, which is a loss before even counting product costs.
Should I include tax in revenue?
Usually not. Use revenue net of sales tax or VAT so that the figure reflects money the business actually keeps.
Sources: Google Ads Help — About Target ROAS bidding