Runway calculator. Months left, four scenarios.
Set cash on hand, monthly burn, optional monthly revenue. We compute runway in months, the extinction date, and chart the cash trajectory across four burn scenarios so you can see what tightening or expanding the burn does to runway.
Set cash on hand and monthly burn (and optional monthly revenue). We compute runway in months and chart the cash trajectory across four burn scenarios — current, +10% (creep), -10% (easy cuts), -25% (restructure). Pure browser math, your numbers stay on your machine.
Total cash out per month (salaries, infra, marketing, etc.).
Cash inflow per month. Subtracted from burn to get net burn.
Privacy: calculation happens in your browser. Nothing is sent or logged.
Four bands. What each one means.
Strong (18+ months). The position every founder wants to fundraise from. With 18+ months of runway, you can launch a fundraise with 12 months of cash still on the balance sheet. Investors see no urgency, you don't have to take the first term sheet, you can play multiple firms against each other for terms. Investors call this "fundraising from strength." Aim for this band whenever you close a round.
Comfortable (12-18 months). Watching, not panicking. The default for most healthy startups between rounds. Plan to launch the next fundraise when you're at 8-10 months — that gives you 4-6 months to close, leaving 4-6 months of cash buffer at signing. Below 12 months you start moving toward pressure-mode and the terms get worse.
Tight (6-12 months). Pressure-mode fundraising. You need to close a round in the next 3-6 months. Investors know this and price accordingly — expect lower valuations, more dilutive structures, board control concessions. If you can't close, the -10% and -25% cost-cut scenarios become real options to extend runway and avoid a down-round.
Critical (<6 months). Either you have a term sheet already or you're in restructure mode. Bridge loans (convertible notes from existing investors) buy you time but at a cost — additional dilution, sometimes punitive terms. Layoff / restructure decisions need to happen before this band, not in it. The cost of waiting until 4 months remaining is much higher than acting at 8 months.
Four jobs this tool covers.
Job 1: Monthly board prep. Update the inputs each month with last-month's actuals, screenshot the chart, drop into the board deck. The four-scenario view is what investors and board members actually want — not just current runway, but how much runway you can buy back through cost discipline.
Job 2: Pre-fundraise scenario planning. Before launching the next round, model what runway looks like at the close-target ($X raised) and what runway looks like if the round comes in 50% of target. The scenario side-by-side tells you whether the partial-raise outcome is survivable or whether you need to commit harder to the cost-cut path before pitching.
Job 3: Cost-cut decision support. When the board asks "should we cut the marketing budget by 20%?", the calculator gives you the runway delta in months. A cut that buys 4 months of additional runway looks different from one that buys 4 weeks. Quantifying the trade-off makes the conversation faster and the decision better.
Job 4: Hire / freeze decisions. Each new hire moves the burn line. Use the +10% scenario to estimate what 1-2 senior hires plus their fully-loaded cost (salary + equity + benefits + tools) does to runway. Then decide whether the hire is worth that many months of runway. Pair with our Blended CAC Calculator if the hire is in growth/marketing.
Six questions users ask.
Should I use gross burn or net burn?
Net burn — the actual cash outflow per month after revenue. Gross burn (total spend before revenue) misleads if you have meaningful revenue. We let you enter both: monthly burn (gross spend) and monthly revenue (offsetting inflow); the calculator subtracts to get net burn for runway. If you're pre-revenue or revenue is below 10% of burn, gross burn alone is fine. For everyone else, net burn is the operating signal.
What runway is healthy?
Industry rule of thumb: 18 months minimum. The reasoning — fundraising takes 3-6 months on the optimistic end, 6-12 on the realistic end. With 18 months runway you can launch a fundraise with 12 months left, giving you negotiating room. With 12 months you have to fundraise in pressure-mode. With 6 months you're in survive-mode and term sheets reflect that. Below 6 months is bridge-loan territory. The verdict bands here use 18+/12-18/6-12/<6 as the cuts.
What if my burn varies month-to-month?
Use the trailing-3-month average as your input. Single-month burn distorts during one-off events (annual subscriptions billed all at once, AWS-credit drawdowns, employee equity vesting). Trailing 3 averages out the spikes. For runway projection, the calculator assumes constant burn going forward — adjust the input if you've signed an obvious next-month change (new hire, renewal cliff, contract end). For irregular burn forecasts, build a proper monthly cash-flow model in a spreadsheet; the calculator is for the constant-burn baseline.
Why are there four scenarios?
Decision-making input. Current burn is the baseline. +10% asks 'what if costs creep up' (almost always do — new tools, raises, scope expansion). -10% is the easy-win scenario from cancelling underused SaaS, paring down marketing, freezing ramps. -25% is layoff-or-restructure territory — the cut you'd make if facing a 6-month runway cliff. Seeing all four side-by-side lets you decide whether the easy cuts are enough or whether you need the deeper one.
How does this differ from gross margin or unit economics?
Runway is a cash-and-time question — when do you run out, given current burn. Gross margin and unit economics are a per-customer profitability question — does each customer make money. Healthy unit economics means you can scale revenue faster than burn; bad unit economics means scaling makes runway worse. For SaaS specifically, pair runway with our LTV:CAC Ratio tool — those two together tell you both 'when do I run out' and 'will scaling help or hurt.'
Is the data I enter sent anywhere?
No. Calculation happens entirely in your browser. The page is static HTML; the only network request is the initial page load (which fetches Chart.js from jsDelivr CDN). Safe for sensitive financial projections, internal burn forecasts, or any number you wouldn't want shared with a third party. We never see your numbers.