Burn Rate & Runway Calculator

Burn Rate & Runway Calculator is a free, browser-based tool built for one job: startup cash runway, gross/net burn & zero-cash date with a depletion chart. It is part of ToolsMonk's business tools collection, so you can finish the work without downloading software, creating an account, or jumping between multiple websites.

This tool is especially useful for workflows such as knowing how many months of runway you have before you need to raise or reach profitability, testing what a hiring plan does to the zero-cash date before you commit to it, and preparing the runway figure for a board pack or an investor update. Because it runs directly in your browser, you can use it on desktop, tablet, or mobile while keeping the process fast and easy for one-off tasks as well as repeat work.

The design goal is simple: practical output on the first try, with a privacy-friendly workflow and the rest of the ToolsMonk library one click away.

The Burn Rate and Runway Calculator takes your cash balance, monthly spend and monthly revenue, and returns gross burn, net burn, runway in months and a zero-cash date, with a chart of the depletion curve. It is the arithmetic every board pack and investor update opens with.

The two burn figures answer different questions and both matter. Gross burn is total operating spend, ignoring revenue: it is your real cost base, and it is what you would have to cover if revenue stopped tomorrow. Net burn subtracts revenue and is the rate your balance actually falls, which is what runway is calculated from. Reporting only net burn hides the size of the cost base; reporting only gross hides how long you have.

The straight-line runway that comes out of the simple calculation is a starting point rather than an answer, because costs almost never stay flat. Headcount grows, contracts renew upward, infrastructure scales with usage, and annual bills arrive in lumps that no single month reveals. Modelling burn increasing in line with your actual hiring plan and known commitments usually shortens the runway noticeably, and that shortened figure is the one worth planning against.

What counts as burn is where optimistic numbers usually originate. It should be all operating cash leaving the account: salaries and contractors, rent, software and infrastructure, marketing, professional fees, everything. The two most frequent omissions are annual and quarterly payments, which are invisible in a typical month and then land all at once, and the employer costs on top of headline salaries, which are consistently underestimated.

The zero-cash date is the output that turns this into a decision, but only if you work backwards from it. A fundraise commonly takes three to six months from first conversation to money in the bank, and frequently longer. The date that matters operationally is therefore the zero-cash date minus that period, minus a buffer. Confusing the two is how companies end up raising from a position of necessity rather than strength.

On how much runway to hold, the common investor convention is 18 to 24 months after a round, precisely so the next raise can begin from strength. Below twelve months the negotiating dynamic changes, because your position is visible. Below six is generally treated as a crisis. These are conventions rather than rules and they move with market conditions, but they are the frame most boards will apply to the number this calculator gives you.