ROI to ROAS Calculator
Turn ROI into ROAS—or ROAS into ROI—with the total cost and ad spend behind each number. When those costs differ, one ratio alone cannot pick a single answer.
ROI to ROAS Calculator
Enter ROI as a percentage. -100% means zero revenue.
Include every cost used in your ROI calculation.
Enter only the ad spend used as the ROAS denominator.
Why this matters
Why convert ROI to ROAS the careful way?
ROI and ROAS divide by different costs. Convert through revenue—or confirm ad spend is the whole cost—before treating the numbers as the same story.
Finance often reports ROI. Ad platforms report ROAS. Mixing them without the cost split is how teams argue past each other.
Skip the cost split and the same 50% ROI can look like 6× ROAS in one setup and 3× in another.
Do it right and you can:
- See the ROAS that matches your ROI and cost split
- Spot when a ratio-only shortcut is unsafe
- Keep each metric on its own denominator
Before you convert
What has to match before you convert?
Enter total cost and ad spend from the same campaign, period, currency, and conversion-value definition.
ROI to ROAS example
Why can the same 50% ROI become 6× or 3× ROAS?
Hold ROI at 50% and total cost at 800. Implied revenue stays 1,200. Change only the ad-spend share—and ROAS flips.
ROI
50%
Total cost
800 units
Implied revenue
1,200 units
800 × (1 + 50%)
Then divide by ad spend
The denominator changes by scenario.
Scenario A: lower ad-spend share
1,200 ÷ 200
6× ROAS
Scenario B: higher ad-spend share
1,200 ÷ 400
3× ROAS
What stayed the same?
ROI stays at 50% because its top and bottom use the same total cost. ROAS changes because the ad-spend denominator changes.
The rule: You need the total-cost and ad-spend relationship. A ratio alone cannot choose one ROAS when those amounts can differ.
What this example leaves out
- This is hypothetical, not a customer result or public-user data.
- It depends on the total cost you supply; it cannot find costs that were omitted.
- It does not fix attribution gaps, mixed reporting windows, or different conversion-value rules.
ROI and ROAS formula
How do you convert ROI to ROAS?
When total cost and ad spend differ, restore implied revenue first. Then apply each metric's own denominator.
Quick lookup
What if ad spend is the only cost?
Use this table only when ad spend is the entire cost in the ROI calculation. If total cost includes more, enter both amounts in the calculator instead.
| ROI | ROAS |
|---|---|
| 0% | 1× |
| 50% | 1.5× |
| 100% | 2× |
| 200% | 3× |
| 300% | 4× |
| 400% | 5× |
Shortcut: ROAS = (ROI ÷ 100) + 1 when ad spend is the full ROI cost.
Common mistakes
What can a ROI to ROAS conversion not tell you?
Common errors
- Treating ROI and ROAS as interchangeable without checking their denominators.
- Mixing revenue, spend, or costs from different dates, currencies, campaigns, or attribution windows.
- Using a ratio-only shortcut when total cost includes more than ad spend.
What this result cannot decide
- It cannot prove profitability—omitted costs and conversion value can change that call.
- It cannot fix attribution uncertainty or recover costs you did not supply.
- It cannot produce one unique conversion from ROI or ROAS alone when total cost and ad spend are not known to match.
Sources
Where do these ROI and ROAS definitions come from?
This calculator uses ROI with total cost and ROAS with ad spend. The shortcut appears only as a confirmed special case.
ROI (return on investment)
Google Ads describes ROI as net profit relative to costs—roughly revenue minus total costs, divided by total costs. What counts as cost depends on your goal.
Google Ads: About return on investmentROAS (return on ad spend)
Google Ads defines ROAS as total conversion value divided by total spend. That value may be sales revenue, margin, or another tracked amount.
Google Ads: ROAS glossary entryWhat these definitions do not settle
They guide the math. They do not standardize your attribution model, cost ledger, or conversion-value policy.
Last reviewed
August 1, 2026. Recheck the linked source and your reporting definitions before using a result for a business decision.
ROI to ROAS conversion FAQ
What should you do next?
Related tools
Calculate ROAS from attributed revenue and ad spend
Calculate a cost-based ROAS threshold
Related guides
Learn how the metrics use different denominators
Check the ROAS input contract and formula