Rex says
Money math without the spreadsheet headache. Plug in your numbers and I'll show you exactly where the dollars land.
Try a scenario
Click to load — tweak from there.Inputs
Result
Projected annual expansion ARR
$432,000
Projected new monthly recurring revenue
$36,000
Net new licensed seats
1,440
Projected total seats
13,440
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How to use this
- 1Enter total current seats across customers.
- 2Enter annual seat growth rate (%).
- 3Enter price per seat ($/mo).
- 4Enter new hires who get licensed (%).
- 5Read your projected annual expansion arr on the right — it updates as you type.
- 6Hit Share to keep the scenario or send it to someone.
About this calculator
Per-seat pricing models grow revenue automatically as customer teams hire and adopt the product more broadly, without any new sales activity. This calculator projects seat expansion revenue based on your current customer base's seat count, an assumed seat growth rate (driven by customer headcount growth and internal adoption), and price per seat, giving you a forecast of how much ARR shows up purely from existing accounts growing headcount. This is a distinct growth lever from logo acquisition or price increases, and it's why seat-based SaaS companies (e.g. project management, communication, or HR tools) often show strong NRR even with modest new-logo growth: their existing customers' headcount growth does a meaningful share of the compounding for them. The risk is the inverse during downturns — when customers do layoffs or hiring freezes, seat-based revenue can contract fast and unpredictably, which is exactly what many SaaS vendors experienced in 2022-2023 as tech company headcounts shrank.
Worked example
Using the values the calculator loads with:
Inputs
- Total current seats across customers: 12000
- Annual seat growth rate: 15 %
- Price per seat: 25 $/mo
- New hires who get licensed: 80 %
Results
- Projected annual expansion ARR: $432,000
- Projected new monthly recurring revenue: $36,000
- Net new licensed seats: 1,440
- Projected total seats: 13,440
What each field means
Inputs
- Total current seats across customers
- The total current seats across customers used in the calculation. Starts at 12000 so you have a working example on load.
- Annual seat growth rate (%)
- The annual seat growth rate used in the calculation, measured in %. Starts at 15 % so you have a working example on load. Accepted range: -50–200 %.
- Price per seat ($/mo)
- The price per seat used in the calculation, measured in $/mo. Starts at 25 $/mo so you have a working example on load.
- New hires who get licensed (%)
- The new hires who get licensed used in the calculation, measured in %. Starts at 80 % so you have a working example on load. Accepted range: 0–100 %.
Results
- Projected annual expansion ARR
- Returned as a money amount in US dollars and shown as the headline result. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Projected new monthly recurring revenue
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Net new licensed seats
- Returned as a whole number. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Projected total seats
- Returned as a whole number. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
FAQ
Why include an adoption rate separate from headcount growth?
Not every new hire at a customer gets licensed immediately, especially if the tool is role-specific rather than company-wide. Adoption rate captures the realistic share of headcount growth that actually converts into paid seats, which is usually well below 100% for anything but universally-used tools like email or chat.
What's a realistic seat growth rate assumption?
It should roughly track your customer base's average headcount growth plus any internal expansion (new departments adopting the tool). For a base of mostly stable enterprise accounts, 5-10% is typical; for a base skewed toward high-growth startups, 15-25%+ is plausible, but revisit this assumption during macro downturns when hiring slows broadly.
How does seat-based pricing compare to usage-based for expansion?
Seat-based expansion is more predictable and easier to forecast since it tracks headcount, a relatively stable metric, while usage-based expansion tracks actual product consumption, which can grow faster (compounding with usage intensity, not just headcount) but is harder to forecast and more sensitive to short-term demand swings.
What happens to seat revenue during layoffs?
It contracts, often quickly, since removing seats is usually a low-friction action for a customer's IT admin compared to canceling a contract outright. This is why many seat-based vendors added minimum seat commitments or annual contracts with true-up-only terms to smooth this volatility.
Accuracy and limitations
- Results are estimates before tax, fees, and inflation unless an input explicitly covers them.
- Rates are treated as fixed for the whole period — variable-rate products will drift from this projection.
- This is educational maths, not financial advice. Check anything contractual with the lender or your accountant.
Related tools
Expansion Revenue Rate Calculator
Measure how much of your growth comes from existing customers spending more.
Usage-Based Revenue Forecast Calculator
Forecast consumption revenue from usage volume, growth rate, and unit pricing.
Net Revenue Retention (NRR) Calculator
See how much revenue your existing customers generate a year later, expansion included.
Cite this calculator
Writing about this topic? Grab a citation — every link helps keep these tools free.
RevenueLab. (2026). Seat Expansion Revenue Calculator. Retrieved from https://www.revenuelab.fyi/toolbox/seat-expansion-revenue
<p>Source: <a href="https://www.revenuelab.fyi/toolbox/seat-expansion-revenue" target="_blank" rel="noopener">Seat Expansion Revenue Calculator — RevenueLab</a> (2026).</p>
Source: [Seat Expansion Revenue Calculator — RevenueLab](https://www.revenuelab.fyi/toolbox/seat-expansion-revenue) (2026).