Latest / Cash Flow Conversations with Fexingo: Working Capital, Receivables, and Small Business Finance / How Late Payments Accumulate Like Interest on Your Business
Transcript
- Lucas: You know that moment when a customer who always pays 30 days late sends a big order and you feel that little knot in your stomach? Luna: Oh, I know that knot. It's the 'here we go again' feeling. Lucas: Right. And most business owners just write it off as 'the cost of doing business.' But what if I told you that a single late-paying customer can cost you tens of thousands of dollars a year, even if they eventually pay every invoice in full? Luna: That sounds dramatic, but I've seen it happen. Let me guess — it's about the time value of money, right? Lucas: Exactly. But more specifically, it's about the compounding effect of late payments. Here's the example I want to walk through today. Say you have a customer who consistently pays 60 days after invoice. Your average invoice to them is $10,000. And your business has a cost of capital — let's say 8 percent annual, which is conservative for a lot of small businesses right now in mid-2026. Luna: So that $10,000, if they paid in 30 days, would cost you about $66 in carry cost. But at 60 days, it's double — $132. That doesn't sound huge. Lucas: Per invoice, it's not. But here's the compounding piece. If that customer sends you one $10,000 invoice per month, and every single one of them is 30 days late beyond your terms, you are effectively carrying a permanent $10,000 loan to that customer. Over a year, the carry cost at 8 percent is $800. Over five years, $4,000. And that's just for one customer. Luna: Okay, so the compounding isn't on the late payment itself — it's on the fact that the delay becomes a permanent feature of your balance sheet. Lucas: Bingo. And most businesses have multiple customers like this. Let's say you have five customers, each with $10,000 in average receivables outstanding 60 days past your net-30 terms. That's $50,000 in permanent receivables that are essentially zero-interest loans. At 8 percent cost of capital, that's $4,000 a year — a very real expense that never shows up on your income statement as a line item. Luna: And that's just the direct cost. There's also the opportunity cost — what you could have done with that $50,000 if it were in your bank account. Lucas: Precisely. And here's where I think a lot of owners miss the real insight. When you calculate the effective discount you're giving by accepting late payment, it's often way bigger than you think. Let's do the math. If a customer pays 30 days late, and your cost of capital is 8 percent, the effective discount you're giving them is roughly 0.67 percent per invoice. That's not huge. But if they pay 60 days late, it's 1.33 percent. At 90 days, it's 2 percent. At 120 days — which is not uncommon in some industries — you're giving a 3.3 percent discount. That's real margin erosion. Luna: So the customer who brags about never asking for a discount might actually be getting one anyway, just by paying late. Lucas: That's exactly right. And they probably don't even realize it. But you, as the business owner, are eating that cost. Now, here's a practical tool I want to share. I call it the 'late payment cost spreadsheet.' It's a simple model where you list every customer, their average invoice amount, their typical payment delay beyond terms, and your cost of capital. Then you calculate the annual carry cost for each customer. It's eye-opening. Luna: So you'd end up with a list that says, 'Customer A costs us $600 a year in carry cost, Customer B costs us $1,200,' and so on. Lucas: Exactly. And then you can prioritize which customers to have a conversation with about payment terms. Or, if they're strategic customers, you can at least factor that cost into your pricing. If you know a customer is going to pay 60 days late, you can build a 1.3 percent surcharge into your quote — not as a penalty, but as a cost recovery mechanism. Luna: And if they push back, you can show them the math. 'Hey, we love working with you, but our cost of capital means we need to either adjust terms or adjust pricing.' Lucas: Right. And that conversation is actually easier if you frame it transparently. Most customers don't realize they're costing you money. They just think they're being 'flexible' with their own cash flow. But the thing is, by delaying payment, they're effectively using you as a low-cost lender. Luna: And you're probably not a bank. Your job is to deliver a product or service, not to finance your customers' working capital. Lucas: That's the key insight. Now, I want to talk about a specific scenario that makes this even worse — the 'just this once' trap. A customer who always pays on time suddenly asks for a 30-day extension 'just this one time.' You say yes because they're a good customer. But then the next order, they're 30 days late again. And the next. Suddenly, you've given them permanent 60-day terms without ever formally agreeing to it. Luna: And the cost compounds because now you have a new baseline. So that one-time exception becomes the new normal. Lucas: Exactly. And that's why I recommend that every business have a formal late payment policy that includes a cost of capital charge. Not a punitive late fee, but a transparent charge that reflects your actual borrowing cost. Some businesses do it as a percentage per month — say, 1 percent per month on the outstanding balance after 30 days. That's 12 percent annualized, which covers most small business cost of capital and then some. Luna: So you're basically saying, 'If you want to use our money, here's the interest rate.' Lucas: Precisely. And if you put that in your terms and conditions from day one, it's not adversarial — it's just business. The customer can choose to pay early and avoid the charge, or pay late and cover your cost. Either way, you're not losing money on the carry. Luna: I think a lot of owners worry that charging interest will scare customers away. But in my experience, most B2B customers actually respect it — as long as it's standard and applied consistently. Lucas: Yeah, and the ones who complain are often the ones who benefit most from the current system. So it's a useful filter. But there's another angle here that I want to touch on — the psychological cost. When you have a big chunk of receivables sitting out there, it creates anxiety. You check your bank account every morning. You spend mental energy chasing payments. That cognitive load has a real cost too, even if it's hard to quantify. Luna: Absolutely. And that's the cost that keeps owners up at night. The spreadsheet cost you can calculate; the worry cost is harder. Lucas: So what's the one takeaway I want listeners to walk away with? It's this: late payments are not just a cash flow inconvenience. They are a direct, measurable cost that erodes your margins. And the longer a payment is delayed, the more that cost compounds. If you can reduce your average receivables aging by just 10 days, you might add a full percentage point to your net margin — without selling a single extra dollar of revenue. Luna: That's a powerful number. So track it, measure it, and then act on it. Start with that spreadsheet. Lucas: Exactly. And if you want to take it a step further, set up an automatic reminder system — email or text — that goes out three days before an invoice is due, the day it's due, and three days after. That alone can shave 5 to 10 days off your average collection time. It's not pushy; it's professional. Luna: Yeah, and it's consistent. Customers learn that you follow up. That alone changes behavior. Lucas: Alright, let's wrap it up with a challenge. This week, open your receivables aging report. Pick your three slowest-paying customers. Calculate the annual carry cost for each using your cost of capital. Then decide: have a conversation, adjust terms, or build it into pricing. That exercise alone could be worth thousands a year. Luna: And if you find this kind of practical finance useful, you know what keeps these episodes coming — listener support. If today's conversation moved your thinking forward, consider buying the team a coffee at buy me a coffee dot com slash fexingo. It's a simple way to keep this ad-free and focused on what actually helps. Lucas: Yeah, we really appreciate that. And it makes a difference. So back to the numbers — I want to leave you with one more calculation. The rule of thumb I use: every 30 days a customer pays past your terms, you are effectively giving them a discount equal to your annual cost of capital divided by 12. So at 8 percent, that's about 0.67 percent per 30 days. That's not huge on one invoice, but over a year of invoices, it adds up. Luna: And if you have multiple customers doing that, you're running a de facto lending business at zero interest. That's a bad business model. Lucas: Exactly. So know your numbers, have the conversation, and protect your margins. That's it for this episode of Cash Flow Conversations. Luna: Thanks for listening, and we'll see you next time.