When does each segment pay back acquisition cost, and how does it compound across the relationship?
№ 009 · Segment ROAS curve
Definition
MetricCumulative gross profit per segment cohort vs fully loaded CAC over months since acquisition
Unitcumulative gross profit as multiple of CAC (1.0x = payback)
Cumulative gross profit per acquired customer divided by their CAC, plotted across 24 months. Each line is a segment; crossover above 1x is payback. Build by tracking acquisition cost and monthly gross profit per cohort by segment. Example: Enterprise crosses 1.0x at M14, hits 4.5x at M24; SMB at M9, plateaus at 2.0x.
- ROAS
- Return on ad spend. Revenue attributed to a campaign divided by the spend on that campaign.
- CAC
- Customer acquisition cost. Fully loaded sales and marketing spend in a period divided by new customers won in that period.
- SMB
- Small and medium business. Segment label, usually under 200 employees or a defined contract-value band.
Benchmarks
| Bottom 30% | Median | Top 30% |
|---|---|---|
| Crosses 1.0x after month 24 or never; curve flattens post-payback because the cohort contracts | Crosses 1.0x around month 16-18 blended; slope after payback determined by segment NRR | Crosses 1.0x by month 6-12; reaches 3x+ CAC within 3 years (the classic LTV:CAC floor) |
Private B2B SaaS, gross-margin-adjusted customer economics, CY2024-2025 data; this is customer-cohort ROAS by segment, not advertising channel ROAS (that family lives in the Marketing section) · The curve is CAC payback (card 012) extended past 1.0x: the crossing point comes from payback benchmarks, the post-crossing slope from segment NRR. No source publishes the full curve by segment; the composite here is assembled from payback and retention benchmarks and flagged accordingly. Enterprise crosses later but compounds harder (118% NRR median); SMB crosses earlier and flattens (97% NRR).
| Category | Bottom 30% | Median | Top 30% |
|---|---|---|---|
| By ACV band (months to cross 1.0x) | any band: 24-30+ months | under $5k: ~9 months; $25-100k: 14-18; above $100k: ~24 | under $5k ACV: 6 months or less; $25-100k: 12 or less |
When it looks bad
A segment's curve crosses 1.0x and then goes flat or bends down, meaning the cohort pays back its CAC and immediately starts contracting, so lifetime value converges to barely above acquisition cost.
SMB cohort crosses 1.0x at month 10, sits at 1.3x at month 24 and 1.4x at month 36. A 3:1 LTV:CAC model was assumed in the plan; reality is a segment that should be acquired cheaper or not at all.
What to do about it
- Plot each segment's curve with its own fully loaded CAC (including allocated SDR, tooling and management cost per segment); blended curves hide the segment that never reaches 3x and is quietly subsidized by the others.
- Steepen the post-payback slope, not just the crossing point: a 5-point NRR improvement in a segment moves the month-36 multiple more than a 2-month payback improvement; usage or module expansion is the lever (OpenView: usage-based 125% vs 115% NRR).
- Cut CAC where the crossing is late for structural reasons: for enterprise, Benchmarkit 2025 shows deals above $250k ACV are less acquisition-efficient than $50-100k deals, so consider landing at mid-six-figures scope and expanding rather than elephant-hunting the first contract.
- Set segment-level investment gates in planning: no incremental S&M into a segment whose curve has not demonstrated 1.0x within 18 months and a rising slope thereafter.
Sources
- Aleph and Benchmarkit Median CAC payback 16 months; top quartile 6 months or less; bottom quartile 24+ months getaleph.com ↗
- Benchmarkit CAC payback highly correlated with ACV: median 9 months at ACV under $5k vs 24 months above $100k ACV benchmarkit.ai ↗
- Benchmarkit CLV:CAC ratio tracked alongside payback; deals above $250k ACV show materially lower acquisition efficiency than $50-100k deals benchmarkit.ai ↗
- SaaS Capital Segment NRR (by ACV) sets the post-payback slope: higher-ACV cohorts compound, low-ACV cohorts flatten saas-capital.com ↗
- Bessemer Venture Partners Capital-into-ARR conversion framework: 0.25-0.5x good, 0.5-1x better, 1x+ best; the company-level analogue of the cohort curve bvp.com ↗
- SaaS Mag LTV:CAC of 3:1 remains the viability floor; top-quartile companies sustain 4:1 to 6:1 saasmag.com ↗