Burn Rate & Runway Calculator — Methodology

Step-by-step calculation

Calculate gross burn, net burn, and months of runway from cash balance, revenue, and monthly expenses.

1. 1

   Enter current cash balance

   Bank balance plus liquid assets — the total you can spend.

2. 2

   Enter monthly revenue

   Average monthly income. Use 0 for pre-revenue startups.

3. 3

   Enter monthly expenses

   Total monthly cash outflows — salaries, rent, software, suppliers.

4. 4

   Read burn rate and runway

   Gross burn (total expenses), net burn (expenses minus revenue), and runway in months. The cash exhaustion date estimates when funds run out at current trajectory.

Assumptions and overrides

Runway = cash / net burn. Assumes current-month income and expense levels continue. In practice, expenses creep, hires happen, and revenue is non-linear. Update inputs monthly for accurate tracking.

Every region default on the calculator is editable. If your effective rate, fee, or threshold differs from the headline figure shown, type your own number into the field — the calculator recomputes instantly without leaving this page.

Review cadence and corrections

This methodology and the underlying rate defaults are reviewed at least annually, and immediately following any change to the headline rate from IRS, HMRC, or SARS. Every substantive update is recorded on the public changelog. Spotted an error? See the corrections policy for how to report it.

See the full editorial policy for the standards every page on BusCalcTools is held to.