Burn Rate Calculator - Startup Cash Runway Analysis

Burn Rate Calculator is designed for startup cash runway analysis, where a small change in one input can alter a decision, budget, or performance story. The calculator keeps the assumptions visible beside the result so the number can be reviewed instead of copied blindly. Use the fields as a compact worksheet: enter the values using the units shown on each label, calculate the primary result, then read the supporting lines to understand which driver is moving the answer. The calculation divides net cash used over a historical period by elapsed months and then divides current cash by monthly burn. In plain terms, Monthly burn = (starting cash - ending cash) / months; runway = current cash / monthly burn. The supporting outputs are included because the headline number rarely gives enough context on its own. Margins, rates, totals, variances, or remaining balances explain whether the result is caused by price, volume, time, cost structure, or exposure. Common use cases include board updates, fundraising timing, hiring-plan reviews, expense reduction planning, and comparing runway after a financing or cost-cutting scenario. A practical review usually compares at least three cases: conservative, likely, and optimistic. Change one input at a time so the sensitivity is clear; if a small input movement creates a large output change, document the assumption and look for a better source before presenting the result. Important caveats include seasonal revenue, working-capital swings, one-time expenses, financing receipts, deferred payments, committed hires, and changes in gross margin. The calculator is a deterministic planning aid, not a substitute for professional advice, policy review, tax guidance, legal review, HR judgment, brokerage instructions, or a full financial model. Rounding can also matter when the result will be used in contracts, accounting entries, payroll conversations, or regulated decisions. For best results, keep time periods and units consistent. Enter percentages as ordinary percentage values, such as 8 for 8%, rather than decimals. Runway is the number of months before cash reaches zero at the observed average burn rate. After calculating, compare the answer with an independent estimate or source document and save the assumptions that support the scenario.