How budget.ceo Calculates Runway & Breakeven
Plain-English math, honest assumptions, and a comparison with other burn rate calculators.
The math
Gross burn = sum of monthly operating expenses (salaries, rent, software, services). Revenue is ignored.
Net burn = gross burn − monthly revenue. This is the number that actually depletes the bank account.
Runway (months) = cash on hand ÷ net burn. With no growth and no expense changes, that's the answer.
When you turn on month-over-month revenue growth, revenue compounds each simulated month. The simulator iterates one month at a time:
- At the start of each month, check whether monthly revenue has caught up to effective expenses. If so, return breakeven at that month.
- Otherwise, subtract the month's net burn from cash and apply the growth rate to revenue.
- If cash hits $0 before breakeven, return runway = months survived.
Effective monthly expenses = (base expenses + additional hires × hire cost) × (1 − expense cut %). Hires add cost linearly; expense cuts apply as a flat percentage on the whole base.
Assumptions
| Assumption | Value | Why |
|---|---|---|
| Loaded engineer cost per hire | $12,500 / month | Reasonable mid-2020s US average for a fully-loaded engineer (salary + benefits + tax + tooling). Adjust your base expenses if your number differs. |
| Simulation cap | 600 months (50 years) | Prevents runaway loops for very low net burn or very high growth. You will never hit this in real life. |
| Time granularity | Integer months | Founders think in months. Sub-month precision would imply false accuracy on inputs that are themselves estimates. |
| Starting revenue floor | None — growth disabled when revenue = 0 | Growth compounds on a base. 5% of $0 is $0 forever, so the slider is disabled until revenue is positive. |
What this calculator doesn't model
- Taxes — federal, state, and payroll taxes. Bake an estimate into your expenses if it matters at your stage.
- One-time costs — legal fees, equipment purchases, security deposits, real-estate buildouts.
- Funding rounds mid-runway — the model assumes no new capital arrives. To simulate a raise, add the proceeds to cash and re-run.
- Seasonality — monthly variance in revenue or expenses (B2C holiday peaks, annual contract renewals).
- FX — foreign-currency revenue or expenses are assumed to be already converted to USD at a flat rate.
- Deferred revenue accounting — annual prepaid contracts are revenue when collected here, not amortized monthly.
Burn rate calculators compared
Honest snapshot of how budget.ceo stacks up against other popular burn rate calculators as of 2026. Different tools fit different needs.
| Tool | Free | Shareable URL | Scenario sliders | Breakeven mode | No signup |
|---|---|---|---|---|---|
| budget.ceo | Yes | Yes | Yes | Yes | Yes |
| OmniCalculator | Yes | No | No | No | Yes |
| Wave Apps | Yes | No | Limited | No | No (signup required) |
| Founderpath | Gated | No | Yes | Partial | No |
Each tool has its own strengths: Wave is genuinely useful if you're already using it for bookkeeping; OmniCalculator is great for quick one-shot math; Founderpath is built for revenue-financing customers. budget.ceo's niche is the shareable-URL, no-signup, scenario-slider workflow for founder-to-founder and founder-to-VC conversations.
Linking
Every change to the inputs updates the URL hash, so you can share a specific scenario as a link. Paste it into a board memo, a Notion doc, or a Slack message and your reader sees exactly the numbers you saw. Try the calculator and hit "Copy share link" — that URL is the whole state.