SaaS Revenue Forecast Calculator

A real forecast separates the forces: new and expansion MRR coming in, churn taking out, and compounding doing the rest. This calculator simulates month by month and shows the trajectory.

Inputs

Current MRR

New + expansion MRR / month

Monthly churn rate

Additions growth / month

How fast new MRR itself grows each month.

Months

Results

MRR in 18 months

$62,959

ARR then: $755,510
Total MRR added: $48,959
Months to double MRR: 1

Forecast MRREnd: 62,959.14

Formula

MRRₜ₊₁ = MRRₜ × (1 − Churn) + New MRRₜ

FAQ

Why grow new MRR separately?

Acquisition capacity usually improves (or degrades) over time. Modeling additions growth makes the forecast far more realistic than a flat monthly addition.

How do I sanity-check the output?

Compare implied end-state growth rate and net revenue retention against your history and segment norms — if the forecast implies implausible retention, adjust churn.