The Invoice That Is Quietly Killing Your Cash Flow
A deep dive into accounts receivable — the revenue you earned but have not collected yet.
A few weeks I hosted a webinar with Duncan from Lunos.ai about cash flow forecasting for startups. One question came up three separate times, from three different founders, in three different industries: “How do I get my clients to pay faster?”
It is the right question. But it is also the wrong framing.
The real question is not how to get clients to pay faster. It is why your accounts receivable process is designed to let them pay slowly in the first place.
The Silent Revenue Leak
Here is a number that will ruin your morning: the average small business has 24% of its total revenue sitting in unpaid invoices at any given time. For B2B service companies, it is closer to 35%.
Think about that. A third of the money you have earned — work you have already done, value you have already delivered — is sitting in someone else’s bank account, earning them interest instead of you.
We talked about this dynamic in the profitable-not-fine post. Profit means nothing if the cash is stuck in AR. But what I did not get into last week is just how much that stuck cash actually costs you.
The Compound Cost Nobody Calculates
Late payments are not just an inconvenience. They have a real, calculable cost that most founders never bother to quantify.
Let us say you have $150K in Accounts Receivable (AR) with an average collection period of 52 days. If you could bring that down to 30 days, you would free up roughly $55K in working capital. That is not theoretical money. That is cash you could use to hire, invest, or simply stop worrying about making payroll.
But it gets worse. That $55K sitting in limbo forces you into other expensive decisions. Maybe you take on a line of credit at 12% to cover the gap. Maybe you delay hiring a key role by two months. Maybe you take a bad deal because you need the cash now rather than the right cash later.
The cost of slow AR is never just the float. It is every downstream decision you make because the float exists.
Why Smart Founders Have Dumb AR Processes
I have worked with hundreds of startups at this point. The pattern is almost universal: brilliant product founders with absolutely no accounts receivable process.
Early on, invoices go out whenever someone remembers. Payment terms are whatever the client asked for during the sales process. Follow-up on late payments is awkward and inconsistent because the person sending the invoice is often the same person managing the client relationship.
This is not a character flaw. It is a structural problem. When you are a ten-person company and the CEO is also the head of sales and the de facto collections department, something is going to give. Usually it’s a routine process that “It’s okay if I do this next week instead”. And that’s often your cashflow review.
In other words, AR.
Five Things That Actually Move the Needle
I am not going to pretend there is a magic fix. But after watching what works across a few hundred companies, these are the five changes that consistently make the biggest difference:
Shorten your default terms. If you are offering Net 60 because that is what your first client asked for three years ago, stop. Net 30 should be your standard. Net 15 is better if you can get it. Every day you shave off your payment terms is a day of cash you get back.
Invoice the same day you deliver. Not next week. Not at the end of the month. The day the work is done. The longer the gap between delivery and invoice, the longer the gap between invoice and payment. Psychology matters here — when the value is fresh, the urgency to pay is higher.
Automate your follow-up. This is the single biggest unlock for most small companies. A polite, automated reminder at 7 days, 14 days, and 21 days past due is not aggressive. It is professional. And it removes the awkwardness of the founder having to chase payments personally.
Offer a 2% discount for Net 10. This sounds like you are giving away money. You are not. You are buying cash flow certainty. 2% to get paid 20 or 50 days early is one of the best deals in business finance. Do the math on your cost of capital and you will see it immediately.
Review AR aging weekly. Not monthly. Weekly. It takes five minutes. Look at what is overdue, what is coming due, and what your total AR balance looks like. This one habit prevents more cash crises than any financial tool I have ever seen.
The Connection to Everything Else
AR does not exist in isolation. It connects directly to your burn rate, your cash runway, and your ability to grow without external funding. When your AR process is broken, everything downstream suffers.
At MyRunwayHealth, we don't fix your AR process — that is not our lane. But we do live in your cash flow forecast all week long, which is exactly where slow-paying invoices show up first. AR aging is rarely the most exciting page in your books, but it is often the fastest path to improving cash position without changing anything else about the business. (If you want to actually overhaul the operations side, Duncan at Lunos.ai — who joined me on the March 31 webinar — is who we send people to.)
You do not need to raise money. You do not need to cut costs. You just need to collect the money you have already earned.
When was the last time you actually looked at your AR aging report? If the answer is “what is an AR aging report,” start with Duncan — and we will keep an eye on your cash flow from ours side.