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Hi,

many bootstrappers are secretly flying blind.

You hustle all year, you close deals, you pay the bills as they come in, and you feel like you are making progress. But you don't actually know how much you are spending. Then, the end of the year arrives. Your accountant runs the numbers, hands you your Profit & Loss statement (P&L, in German: “Gewinn und Verlustrechnung”), and you stare at a massive minus.

Suddenly, the cold sweat kicks in. You spent way more than you brought in. You have sleepless nights, anxiety about cash flow, and a deep fear of the year-end financial statement.

If you have ever felt this way, you are not alone. But let's get philosophical for a second: Knowing your numbers and controlling your costs isn't just an annoying accounting task—it is a fundamental skill of being an entrepreneur. Your cash flow should never control you; you must control it.

I used to hate the uncertainty of fluctuating expenses. I wanted peace of mind. That is why I built the second bucket in my cash flow system to act as a strict financial guardrail: The Operating Expenses (OPEX) Account.

Let me guide you through exactly how this works, so you never have to fear a year-end statement again.

Simply put, your OPEX account holds the money you need to run your daily business. If we look at a basic Profit & Loss statement, we differentiate between two main types of costs:

Every business has a different focal point when it comes to costs. I can't go too deep into every specific P&L structure here because it is highly individual and complex. But we can roughly categorize 80% of businesses into two main buckets to help you organize your spending:

Regardless of which category you fall into, you need a plan to control these expenses.

Step 1: Estimate & Multiply by 1.5 If you are just starting out or launching a new project, write down every single cost you think you will have. Then, take that total and multiply it by 1.5. Trust me on this. Everything always takes longer and is more expensive than you think.

Step 2: Map It Out Enter all these expected costs into a simple spreadsheet. Separate them by fixed and variable, and categorize them (Marketing, Sales, Production, Admin). Now you know your baseline.

Step 3: Enforce the Budget Cap (The Magic Step) This is where the OPEX account saves you. Let’s assume you assign 25% of your revenue to your Operating Expenses. (Quick reminder: In this system, 45% of your revenue has already been routed to your [Survival/Payroll Account - link to previous article]).

Here is what happens in reality: You close a project and invoice your client for €10,000. The moment that money hits your account, exactly €2,500 gets transferred into your dedicated OPEX account.

This €2,500 is now your absolute maximum operating allowance for that specific revenue chunk. All your software licenses (like that Google Workspace setup), your raw materials, and your marketing budget must be paid from this specific bucket.

And as your business grows, this scales. If you generate €100,000 in revenue over the year, you have exactly €25,000 allocated to spend on running the company.

If you adopt this habit, you practically force yourself to become highly profitable.

Why? Because your business theoretically only ever causes 25% in costs. You know exactly how much you are allowed to spend based on the money you have actually made.

If you ignore this, you risk the ultimate nightmare: running out of money mid-year or getting hit with a massive back-payment because you lived beyond your company's means.

But if you implement this cap, everything changes. You build a buffer. You sleep soundly at night. You evolve from a stressed-out freelancer into a strategic entrepreneur who knows their numbers.

I originally wanted to include a downloadable tracking sheet for you today, but I am still fine-tuning the template to make it perfect. I will share it with you next week!

In the meantime, take a look at your bank statements and see what your true OPEX percentage is.

Next Sunday, we will tackle the most intimidating account of them all: The Tax Reserve.

Keep building,

Bartosz

In the upcoming editions, we’ll dive into the remaining accounts that protect the business itself:

👉 25% Operating Expenses (Covered today!)
👉 25% Tax Reserve (untouchable)
👉 3% Profit
👉 2% Buffer