Two boards, same growth rate, opposite futures
Picture two Series B SaaS companies on the same Monday. Both grew net ARR 30% last year. Both are raising. Company A added $5M in new and expansion revenue and lost $1M to churn and downsells. Company B added $11M and lost $7M. On the headline slide, they look identical. Underneath, one is a coiled spring and the other is a bucket with a hole in it the sales team keeps refilling at a dead sprint.
The number that separates them is the SaaS Quick Ratio: every dollar of revenue you gained divided by every dollar you lost. Company A's ratio is 5.0. Company B's is roughly 1.57. Same growth, radically different quality of growth — and quality is the only thing that survives a 2026 data room.
What makes the Quick Ratio sharper than Rule of 40 or even net revenue retention is that it refuses to net anything out. Rule of 40 lets profit hide a growth problem. NRR collapses your whole base into one percentage. The Quick Ratio puts gross inflow on one side and gross outflow on the other and forces you to look at both at full size. You can't average your way out of it. According to KeyBanc Capital Markets' annual SaaS survey work, the gap between top-quartile and median operators has been widening on exactly this dimension — not how fast you grow, but how cleanly.
The formula, and why the median fell off a cliff
The metric came out of Mamoon Hamid's work at Social Capital, and the math is something you can run on the back of a board deck:
SaaS Quick Ratio = (New MRR + Expansion MRR) / (Churned MRR + Contraction MRR)
Note what's in each bucket. The numerator pairs new logos with expansion from your existing base. The denominator pairs full churn (a customer leaves) with contraction (a customer stays but shrinks their seats or tier). Most founders track new and churn religiously and let expansion and contraction live in a spreadsheet nobody reconciles. That's where the number lies to you.
Here's the part that should make you sit up: per ChartMogul's SaaS growth data, the median Quick Ratio has slid to roughly 1.82, down from about 2.55 in 2021. That's not a rounding error. It means the typical SaaS business today loses nearly a dollar for every dollar-and-eighty it adds. Half the market is on a treadmill it doesn't fully see.
Read your number honestly
- Above 4 — clean engine. Four dollars in for every one out. Every sales rep you add is profitable to add, because they aren't running to replace a leak. This is the only zone where "hire more sellers" is the right answer.
- 2 to 4 — the grind. Where most Series B companies stall. You're growing on effort, not on a flywheel. Valuation tends to cap here because the buyer can see how much of your growth is just refilling.
- 1 to 2 — masking a defect. You're spending acquisition dollars to paper over a product or onboarding failure. The fix is upstream of sales.
- Below 1 — you're contracting. This is a turnaround conversation, not a growth one.
Why 4 is the line and not 3
Churn compounds against your base, and your base only gets bigger. At $5M ARR a 15% churn drag is $750K your sales team can outrun. At $40M ARR that same 15% is $6M of hole to fill before you've grown a dollar. A 2.0 ratio that felt survivable at Series A becomes the thing that quietly eats your Series C. The higher you scale, the more a sub-4 ratio asks of a sales org that physically cannot keep up.
What I actually do when the number is broken
When a founder shows me a Quick Ratio of 2.1 and asks how to get to 4, the instinct in the room is always the same: lean on the VP of Sales to close more. It's almost always the wrong lever. A weak Quick Ratio is a denominator problem wearing a numerator costume — you're losing too much, not winning too little. Here's the order I work it.
First, separate churn from contraction
Pull the two halves of your denominator apart and look at them as distinct failures. Full churn usually means the product never delivered the promise made in the sale — start with gross revenue retention; under 85% and you have a delivery problem no marketing budget fixes. Contraction is sneakier: customers staying but shrinking. That's usually pricing, seat sprawl, or a feature they adopted and then abandoned. The two need different owners and different fixes, and lumping them together hides which one is killing you.
Second, mine expansion before you buy a new logo
Expansion sits in your numerator and it's the cheapest revenue you will ever book — no cold acquisition cost, a customer who already trusts you. Operators with elite ratios commonly source a meaningful share of their gains from the existing base rather than net-new. If your SaaS Magic Number is weak, that's a signal to point capacity at expansion plays — usage-based upsell, tier migration, seat growth — before you fund another outbound team.
Third, refuse to launder a discount as a win
This is the one that breaks in diligence. When a customer threatens to leave and your CS team cuts a 20% discount to keep them, that is contraction MRR — it belongs in your denominator, not booked as a save in your numerator. Teams under pressure quietly reclassify those, and the inflated ratio looks great until a buyer's analyst rebuilds the bridge from raw billing data and watches it collapse. The honest number is the one you can defend line by line.
Run your own ratio this week. Pull last quarter's new, expansion, churn, and contraction MRR — the four numbers, not the netted summary — and divide. If you land under 4 and want a second read on which half of the denominator is the real bleed, that's the kind of diagnostic we do fast.
