Gross Revenue Retention (GRR)
Your revenue floor — how much of the existing base survives churn and contraction, before any expansion.
What is it?
Gross Revenue Retention is the percentage of last period's MRR that survives into this one, counting only what you lost — churn and contraction — and ignoring expansion entirely. It answers a deliberately pessimistic question: of the revenue I already had, how much did I keep? Because expansion is excluded, GRR can never exceed 100%.
It is your revenue floor. Net retention can be flattered by a handful of big upgrades; gross retention strips those out and shows the raw durability of the base. Two companies with identical NRR can have very different GRR, and the one leaking more underneath is the more fragile business.
How to calculate?
Take the MRR from existing customers at the start of the period, subtract churn and contraction over the period, and divide by that starting MRR. Ten thousand dollars of starting MRR that loses $800 to contraction and gives back nothing from expansion retains $9,200 — a GRR of 92%. Expansion, however large, is left out on purpose.
Read GRR next to NRR: the gap between the two is exactly how much expansion is masking. A GRR below 85% is a warning that retention needs fixing before you spend another dollar on acquisition.