ROAS vs. ROI — what marketers actually mean
ROAS measures revenue divided by ad spend. ROI measures profit divided by ad spend. They diverge significantly: a brand selling $100 hand soap with 80% gross margin can hit profit at 2:1 ROAS. A drop-shipper selling $100 electronics at 12% margin needs 9:1 ROAS just to break even on the ad before fulfillment costs. When agencies and tools say "ROAS" they almost always mean revenue-to-spend, not profit-to-spend.
Target ROAS by channel and stage
Prospecting (cold audience): 1.5–2.5x for most consumer brands, 2.5–4x for SaaS subscription. Retargeting (warm): 4–8x is normal — the audience already knows you. Branded search: 8–25x and frequently meaningless because much of the revenue would have happened organically. The blended ROAS your CFO sees is a weighted average; high branded-search ROAS hides poor prospecting performance unless you break it down by channel.
Why "break-even ROAS" is the real KPI
Break-even ROAS = 1 / gross margin %. A brand with 40% gross margin breaks even at 2.5x ROAS. Anything above that line generates contribution dollars. Anything below burns cash to acquire revenue. For subscription products, calculate break-even against LTV rather than first-purchase revenue — many DTC brands target 1.0x ROAS on first purchase and rely on the second-order rate to make the unit economics work.
Worked Examples
Shopify brand running Meta ads
| Ad spend | $12,000 |
| Revenue from ads | $48,000 |
ROAS = 4.0x. Each ad dollar returned $4 in revenue.
Healthy by surface number. But at 35% gross margin, contribution is $48K × 0.35 − $12K = $4,800 of actual profit. At 20% margin (typical apparel), this campaign loses $2,400.
B2B SaaS Google Ads campaign
| Ad spend | $25,000 |
| Revenue from ads (year-1 ACV) | $87,500 |
ROAS = 3.5x on year-1 ACV.
Strong if customers stay 3+ years. The same campaign on year-1 ACV alone looks fine but the real LTV-to-CAC ratio is what determines whether this scales — at 80% gross retention and 110% net retention, this customer cohort is worth roughly 4x the year-1 ACV over a 5-year horizon.
Frequently Asked Questions
What's a good ROAS?
Anything above your break-even ROAS (1 / gross margin). A 4:1 ROAS is excellent at 40% margin, mediocre at 25% margin, and catastrophic at 10% margin. Always compare ROAS to your specific break-even, not to industry averages.
How is ROAS different from ACOS?
ACOS (Advertising Cost of Sale) is the inverse of ROAS expressed as a percentage: ACOS = ad spend ÷ revenue × 100. A 4x ROAS is a 25% ACOS. Amazon Ads uses ACOS by default; everyone else uses ROAS.
Does ROAS account for organic lift?
No. Reported ROAS includes only revenue attributed to the ad platform, which usually claims everything in its attribution window (7-day click, 1-day view on Meta). The true incremental ROAS is typically 30–60% lower than reported because some of those customers would have purchased anyway. Geo holdout tests measure incrementality.
Should I use first-purchase or LTV-based ROAS?
LTV-based for any subscription, repeat-purchase, or marketplace business. First-purchase ROAS for true one-time products. Most DTC brands sit in between and use a "predicted LTV at day 30" multiple — typically 1.4–1.8x first-purchase revenue.
Why is my ROAS dropping as I scale?
Diminishing returns. The most efficient audiences and placements get exhausted first. Each additional dollar of spend reaches lower-intent users. A 5x ROAS at $5K/day commonly becomes 3x at $20K/day. The optimization question is whether the incremental volume is still above break-even.
Sources
Theo spent 10 years building reporting stacks for B2B SaaS companies, focusing on the LTV/CAC, ROAS, and payback-period dashboards that boards actually look at. He writes about marketing math the way an operator uses it — not the way an agency sells it.