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.
Worked example
Run live against the same engine this site ships
(/engines/monthly-burn-rate-calculator.js).
The inputs and outputs below are recomputed on every build and
independently re-verified in CI — they are never hand-authored.
Input
- tool
- monthly_burn_rate
- cash_on_hand
- 200000
- monthly_revenue
- 8500
- items[0].name
- Salaries
- items[0].category
- payroll
- items[0].amount
- 15000
- items[1].name
- Hosting
- items[1].category
- infra
- items[1].amount
- 1200
Output
- grossBurn
- 16200
- netBurn
- 7700
- runwayMonths
- 25.97
- byCategory.payroll.amount
- 15000
- byCategory.payroll.percent
- 92.59
- byCategory.infra.amount
- 1200
- byCategory.infra.percent
- 7.41
- itemCount
- 2
- annualBurn
- 92400
Frequently asked questions
- What does the Monthly Burn Rate Calculator calculate?
- 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.
- What inputs does the Monthly Burn Rate Calculator need?
- It takes 2 inputs: lineItems, monthlyRevenue (default 0). Outputs returned: grossBurn, netBurn, byCategory.
- What formula does the Monthly Burn Rate Calculator use?
- The exact computation is: gross_burn = sum(lineItems.monthlyAmount); net_burn = max(0, gross_burn - monthly_revenue)
- Can I verify the Monthly Burn Rate Calculator with a worked example?
- Yes. With lineItems = [{SaaS, 400}, {Payroll, 8000}, {Rent, 1200}], monthlyRevenue = 0. the tool returns gross_burn = 9600, net_burn = 9600.
- Does the Monthly Burn Rate Calculator bundle any external benchmark data?
- No. It runs standard arithmetic on the values you enter; no external benchmark dataset is bundled. Industry references, where relevant, are cited on the adjacent tools' methodology pages.
- What can the Monthly Burn Rate Calculator not tell me?
- 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.