Gross Dollar Retention (GDR) tracks how much of the starting MRR or ARR a company retains after accounting for churn and downgrades, but before including upsell or expansion revenue. Unlike NRR, it cannot exceed 100% and represents the floor of revenue retention.

Example: A SaaS company starts the year with $2M ARR from existing customers. By year end, $1.74M remains after churn and downgrades. The GDR is 87%, meaning the company retained 87% of its base revenue before any expansion.