The Seed Stage Burn Calculator measures how much cash a startup consumes each month after accounting for operating cash inflows. It reports gross burn, net burn, and the share of starting cash used during the period.
Founders can use it to monitor spending discipline and prepare for runway planning. Because accounting profit and cash burn are different measures, the inputs should be based on actual or expected cash movement.
Include monthly operating cash payments such as payroll, software, rent, and marketing.
Add cash received from customers or other recurring operating sources.
Use the unrestricted cash balance available to fund operations.
Compare net burn with gross spending and the implied simple runway.
Gross burn = Monthly operating cash outflows
Net burn = max(0, Cash outflows − Cash inflows)
Simple runway = Starting cash ÷ Net burn
The calculator floors net burn at zero. If inflows equal or exceed outflows, the business has no modeled net cash burn for that month.
Monthly net burn is the amount by which operating cash outflows exceed operating cash inflows.
Large one-time payments, financing proceeds, and changes in working capital can make actual cash movement uneven.
Given: $95,000 in monthly outflows, $35,000 in inflows, and $900,000 in cash.
Calculation: Net burn = $95,000 − $35,000 = $60,000. Simple runway = $900,000 ÷ $60,000 = 15 months.
Result: Monthly net burn is $60,000.
Gross burn is total operating cash outflow. Net burn subtracts operating cash inflow and shows the actual monthly cash consumption.
Usually not for operating burn. Track financing separately so operating performance is not obscured.
A business can be cash-generative, but this calculator displays zero net burn when inflows exceed outflows and identifies no simple burn-based runway.
For planning, allocate them across months only if that reflects the intended model. For cash tracking, use the month when payment actually occurs.
Cash burn reflects cash timing, capital purchases, working capital, and noncash accounting items, while net loss follows accounting rules.