SaaS Monthly Recurring Revenue (MRR) & Churn Rate Calculator

For a SaaS business, MRR and churn are the two numbers that decide survival. Monthly Recurring Revenue shows the base; churn shows how fast it leaks. This calculator combines them to project whether you are growing or slowly declining — a reality many founders miss until it is too late.

Churn's compounding effect is brutal. Losing 5 percent of customers monthly sounds minor but means losing nearly half your base annually, requiring constant new sales just to stand still. The tool makes this visible by projecting revenue with and without churn, so you see the hidden tax on growth that retention work would eliminate.

Expansion changes the math. If existing customers upgrade, net revenue retention can exceed 100 percent, meaning the base grows even with some churn. The calculator models upsell offsetting losses, illustrating why reducing churn and increasing expansion both beat pure acquisition on cost and durability.

Use it for planning and investor conversations. Track MRR and churn monthly, set retention targets, and model how small improvements compound into valuation. Acquisition gets attention, but retention is cheaper and more predictable. The calculator's value is framing churn not as a support metric but as the core growth lever it truly is.