Gross revenue retention (GRR), also referred to gross dollar retention (GDR), tells you how much of your customer revenue you are retaining from the previous year. Conversely, it tells you the churn and downgrades from your existing customers.
GRR is best used in conjunction with other SaaS metrics. GRR tells you how happy your customers are and reflects the stability of your company.
This is how you calculate GRR. You can swap annual recurring revenue (ARR) for MRR if you operate on an ARR basis.
Bessemer Ventures explores gross retention rate by SaaS sub-industries in their report, Scaling to $100 Million.