SaaS Quick Ratio — A Field Guide

The Quick Ratio is the one SaaS metric that answers a question growth rate can't: is this growth durable, or is it one slow sales month away from going flat? A company can show 8% month-over-month growth while quietly bleeding customers, if new bookings are just outrunning churn rather than beating it by a comfortable margin. The Quick Ratio strips that out and shows the underlying health of the revenue engine.

The formula

SaaS Quick Ratio = (New MRR + Expansion MRR) / (Churned MRR + Contraction MRR). The numerator is everything moving revenue up in a given month — new customers plus existing customers who upgraded or bought more seats. The denominator is everything moving it down — customers who cancelled plus customers who downgraded. A ratio of 4 means you're adding four dollars of MRR for every dollar you lose; a ratio near 1 means new bookings are essentially just replacing what churned out the back door, and any slowdown in sales will show up as flat or shrinking revenue almost immediately.

WITH monthly_mrr_movements AS (
  SELECT
    DATE_TRUNC('month', event_date) AS month,
    SUM(CASE WHEN movement_type = 'new'        THEN mrr_delta ELSE 0 END) AS new_mrr,
    SUM(CASE WHEN movement_type = 'expansion'  THEN mrr_delta ELSE 0 END) AS expansion_mrr,
    SUM(CASE WHEN movement_type = 'churn'      THEN ABS(mrr_delta) ELSE 0 END) AS churned_mrr,
    SUM(CASE WHEN movement_type = 'contraction' THEN ABS(mrr_delta) ELSE 0 END) AS contraction_mrr
  FROM mrr_ledger
  GROUP BY 1
)
SELECT
  month,
  new_mrr, expansion_mrr, churned_mrr, contraction_mrr,
  ROUND(
    (new_mrr + expansion_mrr)
    / NULLIF(churned_mrr + contraction_mrr, 0), 2
  ) AS quick_ratio
FROM monthly_mrr_movements
ORDER BY month;

What counts as good

Public benchmarks generally put a Quick Ratio above 4 in healthy territory for growth-stage SaaS, with anything below 2 treated as a warning sign worth investigating rather than an automatic emergency — the right threshold depends on stage and how lumpy your deal sizes are. A one-person self-serve product with thousands of small accounts should have a smoother, more predictable ratio month to month than an enterprise seller closing five deals a quarter, where losing or landing a single large logo can swing the number sharply. Read the ratio as a trend over several months, not a single data point.

Where the metric lies to you

The Quick Ratio is easy to game unintentionally. Large annual contracts that get discounted heavily to close before quarter-end inflate New MRR without reflecting durable unit economics. Grandfathering existing customers out of a price increase suppresses Contraction MRR and flatters the ratio without changing whether those customers are actually happy. And a company that stops offering downgrade paths — forcing unhappy customers straight to cancellation — moves dollars from Contraction into Churn, which changes the ratio's shape even though total revenue lost is identical. Always sanity-check a moving Quick Ratio against the raw MRR movement components, not just the final division.

Wrapping up

The Quick Ratio earns its place next to MRR growth and churn because it forces the same question every month: is the revenue engine adding faster than it's leaking, by a margin wide enough to survive a slow quarter? Calculate it from the same MRR movement ledger you already use for churn reporting, track the trend rather than any single month, and always look at the four underlying components before trusting the ratio on its own.