C4 · Economics & metrics · ratio

LTV:CAC Ratio

Also: LTV/CAC

Definition. LTV:CAC is contribution LTV before acquisition cost divided by allocated acquisition cost for a matched cohort. If LTV is already contribution based, do not multiply by gross margin again. A ratio below one implies negative modeled expected net value under those assumptions, not a loss on every individual customer. The 3:1 rule is a practitioner planning heuristic.

ratio definition established; forecasts and investment hurdles are model- and policy-dependent Last updated 2026-06-18 Source: 3:1 and adjacent score bands are historical practitioner heuristics, not validated universal thresholds or current market requirements.

Formula

LTV:CAC Ratio ratio

LTV : CAC = \frac{L T V _{contribution, before CAC}}{C A C}

Plain English: LTV:CAC = Contribution LTV / CAC

Notation: LTV:CAC = PV(expected customer contribution before acquisition cost) / aligned acquisition cost

Benchmark by stage

Source: 3:1 and adjacent score bands are historical practitioner heuristics, not validated universal thresholds or current market requirements.

Stage	LTV:CAC Ratio	Notes
Concerning	< 1:1	Practitioner heuristic band; inspect assumptions, marginal customer value, cash timing and capacity before changing spend.
Marginal	1:1 – 3:1	Practitioner heuristic band; inspect assumptions, marginal customer value, cash timing and capacity before changing spend.
Good	3:1 – 5:1	Practitioner heuristic band; inspect assumptions, marginal customer value, cash timing and capacity before changing spend.
Best-in-class	> 5:1	Practitioner heuristic band; inspect assumptions, marginal customer value, cash timing and capacity before changing spend.
Suspiciously high	> 10:1	Practitioner heuristic band; inspect assumptions, marginal customer value, cash timing and capacity before changing spend.

Naive vs corrected

Version	Formula
Naive	Revenue LTV divided by partially counted acquisition costs overstates economic recovery; there is no universal inflation percentage.
Corrected	Use contribution LTV/CAC, matched on cohort, currency, period and cost allocation. A constant margin adjustment is valid only if starting with revenue LTV and that margin assumption is appropriate. Do not apply margin twice.

Common errors

Multiplying contribution LTV by gross margin a second time
Assuming sBG necessarily lowers LTV
Combining mismatched customer cohorts or acquisition windows
Inventing a universal WACC-to-ratio threshold formula
Treating 3:1 as an automatic investment decision while ignoring runway, payback, uncertainty and marginal incrementality

Where this sits

Part of the Economics & metrics (C4) cluster in the GTM World Model. Related to the model's "Expected net customer value = contribution LTV - CAC. Discount rates affect LTV through cash-flow timing; required investment hurdles are decision-policy inputs, not a fixed algebraic adjustment to 3:1." equation.

ltv →cac →cac payback →nrr →

How to cite this

@misc{shalvi_gtm_metric_ltv_cac_ratio_2026,
  author = {Singh, Shalvi},
  title  = {LTV:CAC Ratio — GTM World Model Metrics},
  year   = {2026},
  url    = {https://shalvisingh.com/gtm/metrics/ltv-cac-ratio}
}

Singh, Shalvi. "LTV:CAC Ratio — GTM World Model Metrics." shalvisingh.com, 2026. https://shalvisingh.com/gtm/metrics/ltv-cac-ratio