Most SaaS operators already track MRR in a spreadsheet: a column for starting MRR, one each for new, expansion, contraction, and churn, and a formula or two for the totals. Every one of those formulas is ordinary arithmetic. Where a spreadsheet formula goes wrong is not the arithmetic — it's keeping new, expansion, and reactivation MRR out of gross revenue retention specifically, which is the one rule that makes gross retention mean something different from net retention.
A spreadsheet can reproduce every formula this calculator runs — the waterfall total, gross and net revenue retention, and the quick ratio. Building it correctly means writing two separate retention formulas (one excluding growth, one including it), remembering to cap only the gross one at 100%, and never letting a copy-and-edit of one formula quietly turn into the other.
This calculator keeps the six inputs, the full waterfall, and both retention percentages on one screen, with the exclusion rule built into the tool itself rather than into a formula that can drift.
| Question | Where to answer it |
|---|---|
| What's my gross revenue retention this period, excluding growth? | This calculator's readout — the exclusion is enforced in code, not a formula. |
| What's my net revenue retention, including expansion and winbacks? | The same readout, computed independently from the same six inputs. |
| How do I compare several periods or cohorts side by side? | A spreadsheet you build yourself — this tool answers one period at a time. |
| Am I over- or under-charging existing customers on price? | The subscription price impact calculator. |
| Is my data uploaded anywhere? | No. Everything runs in your browser; your figures stay on this device. |
Starting MRR of $10,000, with $1,200 in new MRR, $1,500 in expansion, $100 reactivated, $400 in contraction, and $600 churned this period:
| Line | Amount |
|---|---|
| Starting MRR | $10,000.00 |
| + New / Expansion / Reactivation | +$2,800.00 |
| - Contraction / Churn | -$1,000.00 |
| = Ending MRR | $11,800.00 |
| Gross revenue retention | 90.0% |
| Net revenue retention | 106.0% |
A single retention formula built by copying one cell and swapping the numerator would report the same 106% for both rows, hiding the fact that this period actually lost 10% of its starting base to real churn and contraction — the exact distinction a board update or investor update needs, and the one a rebuilt spreadsheet formula most often collapses into one number.
This page names no specific product — it compares against the generic method of tracking these numbers in a spreadsheet, not a competing calculator or platform.
Yes. Starting MRR plus new, expansion, and reactivation, minus contraction and churn, is ordinary addition and subtraction. The retention percentages and the quick ratio are ordinary division. Every formula this calculator runs can be written in a spreadsheet cell.
That new, expansion, and reactivation MRR never enter the gross revenue retention formula. A spreadsheet has no rule against summing the wrong column into the wrong cell, and the easiest mistake to make by hand is building one retention formula, copying it, and only changing the numerator -- which silently turns gross retention into a second copy of net retention. This calculator computes both from the same six inputs with the exclusion built into the code, not into a formula a future edit can quietly break.
Yes, when you need more than one period side by side, a cohort-level breakdown by signup month, or a chart of the trend over time. This calculator answers one period at a time and does not store or chart history. A spreadsheet you build yourself can track as many periods and cohorts as you want.
No. The calculator runs entirely in your browser. The six numbers you type in are never sent anywhere, and the optional usage counter records only which features were used and the day, never your MRR figures.