Cash, runway and break-even

0:00 Cash, runway and break-even

Here's a sentence that surprises many first-time founders. A profitable business can go bust. Not because it isn't making money on paper, but because the cash arrives too late to pay the bills. In this lecture, you'll learn why profit isn't cash, how to calculate burn, runway and your zero-cash date, how to find break-even, how to run a thirteen-week cash forecast, and how to avoid the new cash traps of AI products, like usage bills that arrive before your customers pay.

0:36 Why it matters

Why does this matter? Because cash is oxygen. You can survive a loss-making month. You can't survive a month where you can't pay salaries or suppliers. The gap between profit and cash comes from timing. Customers pay thirty, sixty, sometimes ninety days after you invoice. Stock ties up cash before you sell it. Equipment uses cash immediately but is expensed over years. Taxes and loan payments arrive on their own schedule. And growth itself can eat cash, because more customers often means more unpaid invoices and more stock. Here's the key idea. Manage cash as carefully as you manage profit, and plan it weekly when it's tight.

1:23 The water tank

Here's an analogy. Think of your bank balance as a water tank. Water flows in from customers and out to salaries, rent and suppliers. Profit tells you whether, over a whole year, more water comes in than goes out. But the tank can run dry in the middle of the year if a big outflow comes before the inflow. Burn rate is how fast the level is falling each month. Runway is how many months until the tank is empty. And your zero-cash date is the day it would run dry if nothing changed. You want to see that day coming a long way off.

2:09 Burn and runway

Let's do the maths. Gross burn is total monthly cash spending. Net burn is cash spending minus cash received. Runway is cash in the bank divided by net burn. For example, illustrative: three million in the bank, nine hundred thousand going out each month, four hundred thousand coming in. Net burn is five hundred thousand. Runway is six months. Now here's the practical rule. Fundraising and reaching break-even almost always take longer than you expect. So set a trigger in advance: when runway falls below a certain number of months, you start fundraising or cutting costs. Don't wait until the last few months.

2:54 Break-even: a café (illustrative)

Now break-even: the point where contribution covers fixed costs. Break-even units equal fixed costs divided by contribution per unit. A simple worked example, illustrative. A café in Manchester has fixed costs of eighteen thousand pounds a month. The average transaction is eight pounds and the variable cost is three pounds twenty, so contribution is four pounds eighty, or sixty percent. Break-even is eighteen thousand divided by four eighty: three thousand seven hundred and fifty transactions a month, about a hundred and twenty-five a day. Or, in revenue, eighteen thousand divided by point six: thirty thousand pounds a month. Now the owner knows exactly what a normal day must look like.

3:42 Improve cash

How do you improve your cash position? Collect faster: invoice promptly, make paying online easy, take deposits on projects and offer annual prepayment. Pay suppliers on the agreed terms, not early, and negotiate longer terms where you can, while keeping relationships healthy. Keep stock lean. Delay hires until they're needed and prefer flexible contracts early on. And plan tax payments so they never surprise you. When cash is tight, switch from a monthly view to a thirteen-week cash forecast, updated every week: opening cash, expected receipts, payroll, suppliers, rent, taxes and loans, and closing cash, with a minimum threshold that triggers action.

4:26 AI-era cash traps

Now the AI-era cash traps. First, usage bills arrive after the usage. A viral week can create a large model bill before customers have paid you, so set spend limits and alerts in your provider's console and watch cost per day. Second, free trials of AI products burn real money, so cap trial usage and verify users. Third, team subscriptions to AI tools quietly pile up; review seats every quarter. And fourth, currency. Many AI and cloud providers bill in US dollars. The UAE dirham and Saudi riyal are pegged to the dollar, which reduces that risk for Gulf businesses, but if you earn in rupees or pounds, exchange-rate moves change your costs.

5:15 Worked example 2: a viral bill (illustrative)

Here's a realistic scenario, illustrative. Two founders in Lahore, Hamza and Zara, launch a free AI CV-writing tool to build an audience. A post goes viral. Usage jumps overnight, and within days the model bill is several times their planned monthly budget, payable in US dollars. They have no spend cap. So they act fast. They set a hard monthly cap and a daily alert in the provider console. They limit free users to three generations after verification. They switch first drafts to a cheaper model. And they launch a paid tier for heavy users. The lesson: in usage-priced products, a budget line isn't enough. You need usage controls.

6:02 Watch me: the calculator

Watch me fill in the runway and break-even calculator from the lesson. Cash in bank today: I type the actual balance, not what I expect next week. Monthly cash out: payroll, rent, tools, model and API bills, supplier payments and tax instalments. Monthly cash in: actual customer receipts, not invoices sent. The sheet gives me net burn, runway and the zero-cash date. Then I set my trigger: start fundraising or cutting when runway drops below a number I choose now. In the break-even section, I include AI usage per unit and payment fees in variable costs, because they're easy to forget and they change the answer.

6:48 Default alive or default dead?

There's a useful question from the investor Paul Graham: are you default alive or default dead? In other words, if nothing changes, with your current growth and costs, will you reach profitability before the money runs out? It's a brutally honest question, and it's worth answering every month. If you're default dead, you have three choices: raise money, cut costs, or grow revenue faster. Usually it's a mix. Decide early, while you still have options, rather than late, when every option is expensive.

7:24 Common mistakes

Let's list the common mistakes. Confusing profit with cash. Not knowing your runway. Starting fundraising too late. Ignoring the cash appetite of growth. Paying suppliers early to be nice while running short. And in AI products: no spend caps, uncapped free trials, and forgetting that dollar-denominated bills move with the exchange rate. One more practical tip. Keep a minimum cash buffer, a number below which you'll act immediately, and make it visible to everyone who makes spending decisions.

7:58 Recap and try this now

Let's recap. Profit isn't cash, because of timing. Know your net burn, runway and zero-cash date, and set a trigger for action in advance. Calculate break-even in units and revenue. Use a thirteen-week forecast when cash is tight. For AI products, set spend caps and alerts, cap free usage, and watch currency exposure. Your try this now: fill in the runway and break-even calculator with your real numbers, write down your zero-cash date, and set your action trigger today. Next, we'll look at funding options, dilution and how to raise money if you need to.