1. Scope
Totals recurring and one-time monthly outflows into a single burn-rate figure and surfaces category breakdown. It does not forecast growth, model dilution, or separate net versus gross burn beyond what the user enters.
2. Inputs and outputs
Inputs
- lineItems array
Each item: label, monthlyAmount, category.
- monthlyRevenue number (currency) default: 0
Optional — used to compute net burn when provided.
Outputs
- grossBurn
Sum of all monthly outflows.
- netBurn
grossBurn − monthlyRevenue (floor at grossBurn when revenue is zero).
- byCategory
Rollup by category for the category chart.
Engine source: src/lib/monthly-burn-rate-calculator/engine.ts
3. Formula / scoring logic
gross_burn = sum(lineItems.monthlyAmount)
net_burn = max(0, gross_burn - monthly_revenue)4. Assumptions
- Line items are steady-state monthly amounts. Annual subscriptions should be divided by 12 before entry.
- One-time items (legal filings, equipment) are handled by the companion Startup Cost Estimator, not this tool.
- Payroll is entered inclusive of employer taxes and benefits, or users should run the Employee Cost Calculator first.
5. Data sources
This tool relies on user inputs and standard arithmetic; no external benchmark data is bundled. When a question depends on an industry reference (for example, typical churn rates or hourly-wage medians), the linked adjacent tools cite their primary sources on their own methodology pages.
6. Known limitations
- Gross-vs-net burn is sensitive to how the user categorises refunds, deferred revenue, and founder salary. The tool takes inputs at face value.
- No scenario layer: to compare best/base/worst, run the tool multiple times and compare.
7. Reproducibility
Input
lineItems = [{SaaS, 400}, {Payroll, 8000}, {Rent, 1200}], monthlyRevenue = 0.
Expected output
gross_burn = 9600, net_burn = 9600.
8. Change log
- 2026-04-24 methodology page first published.