I’m Rennie, founder of Huntr (B2C SaaS, 8 years, 6-person team). I built this to solve a problem that’s been bugging me for years.

There are plenty of MRR forecasting tools: plug in churn, acquisition, ARPU, see where revenue is headed. And there are plenty of cash flow tools: enter expenses, see your burn. But these need to be the same chart. Your runway isn’t a function of expenses alone. It’s how your SaaS metrics interact with your expenses over time.

The thing most tools get wrong: SaaS revenue has lag. When churn creeps up or acquisition slows down, MRR doesn't move in a straight line. The hit (or the bump, when things go well) is steepest in the first few months, then gradually flattens as the compounding plays out. Most founders don't see the shape of it until it’s too late.

The problem is, your brain sees the first two months and draws a straight line. But the curve flattens. So you end up cutting too deep or spending too fast; reacting to a future that was never going to happen.

Airstrip takes your SaaS inputs (new customers/month, churn rate, ARPU), forecasts MRR with the lag modeled correctly, then layers in expenses: payroll with start/end dates, recurring costs, one-time expenses, Stripe fees, owner’s draw, estimated taxes. One chart. Forecast up to 60 months.

What makes it useful for me: ∙ Change any input, runway updates in real time ∙ Hide/show employees to see exactly what cutting or adding a role does ∙ Save scenarios, branch off them, compare ∙ Share via URL; all variables encode into the link, no export needed

No backend. Everything is local storage. No login, no account, I can’t see your data. I use this to run Huntr. Built it because the spreadsheet I’d been maintaining for years finally broke me, and enterprise FP&A tools are $500+/month overkill for a small team.

Totally free to use: https://app.getairstrip.com Learn more about the product: https://getairstrip.com