Most Founders Can't Tell You Their Runway. I Was One of Them.

Berkay Yozgen — Sun, 16 Aug 2026 09:43:02 +0000

€200,000 in the bank, burning €25,000 a month, is eight months. That is the whole calculation.

The math is never the problem. The inputs are. They move every week and nobody keeps up. Someone starts on payroll. A customer pays 40 days late. You double ad spend for a launch. The spreadsheet that knew the answer was last opened a month ago, two of its formulas quietly broke, and now the number you are quoting an investor is fiction.

A few habits fixed this for me.

Log money as it happens

The moment you spend or get paid, the number should move. If you reconcile once a month, you are always looking at the past. Runway is a live number or it is a guess.

Split one-time from recurring

A €10,000 legal bill hits your cash once. A €4,000 retainer hits it every month forever. Only the recurring stuff belongs in your burn. Mix them up and your runway looks scarier than it is, which pushes you into bad decisions.

Know your concentration

If one customer is 40% of revenue, your runway has a hidden cliff. Losing them does not dent the model, it rewrites it. You want to know which customer would hurt most to lose long before the day they churn.

Model the decision before you make it

Before you raise salaries 10% or hire two engineers, you should see what it does to your runway in seconds. If checking costs you a weekend in Excel, you will just not check, and that is how the number drifts.

What I ended up doing

I did the spreadsheet thing for a while. It works if you are disciplined. I was not, because the spreadsheet is boring and the company is always a little on fire.

So I built Plainhub. You type what happened in plain words, "Paid €4,000 for Meta ads," "Hired two engineers," and your runway, burn and MRR update while you type. No bank logins, no imports, no month-end reconciliation. It is the tool I wanted when I gave that investor the wrong number.

Whatever you use, spreadsheet or tool, the point is the same. Stop guessing the most important number in your company. Know it before it turns into a problem.