Ask a shop owner how much customers owe them and you'll usually get a pause, then a guess. The real figure is spread across the back pages of the sales book, a few scraps of paper, and memory.

That's why credit hurts small shops so badly. It isn't that people never pay. It's that nobody is keeping score, so nobody is asked.

A debtors book fixes that. It needs six columns and one rule.

The rule

One page per customer. Not one list for everyone.

On a shared list you can see that somebody took ₦3,000 of goods on Tuesday. On their own page you can see that this is the fifth time this month, they haven't paid anything since the 2nd, and they now owe ₦19,000.

The format

At the top of each page write the customer's name, phone number, where they live or work, and the credit limit you have agreed for them.

DateDetailsTakenPaidBalanceSign

Details says what they took, or how they paid. Taken is the value of goods collected on credit. Paid is money received. Balance is what they owe after this line. Sign is the initials of whoever served them. For large amounts, have the customer sign too.

A page filled in

The figures are invented.

Customer: Mrs Tobi Adewale. Phone: 0800 000 0000. Address: Block 4, Flat 2. Credit limit: ₦20,000.

DateDetailsTakenPaidBalanceSign
2 OctMilk x2, sugar, bread6,4006,400BA
5 OctNoodles carton3,2009,600BA
9 OctCash5,0004,600CN
12 OctRice 5kg, oil 1L7,50012,100BA
20 OctDetergent, soap4,30016,400CN
28 OctTransfer16,4000CN

One glance tells you everything. She buys often, she pays in full at the end of the month, and she has never gone over her limit. This is a customer worth giving credit to.

Now imagine the same page with nothing in the Paid column since the 9th and a balance of ₦31,000. You'd know to stop before the next carton left the shop.

The summary page

Keep a summary at the front of the book and update it on the last day of each month.

CustomerLimitBalanceLast paymentDays since
Mrs Adewale20,000028 Oct3
Mr Okafor15,00014,20030 Sep31
Iya Bisi10,00022,50014 Aug78
Total owed36,700

Two numbers matter here. Total owed is money that belongs to your shop and isn't in it. Many owners find it's larger than a week's sales. Days since shows who has gone quiet. Iya Bisi is over her limit and hasn't paid in 78 days. That's the conversation to have first.

How it connects to your other books

A credit sale is still a sale. It goes in your daily sales record book marked "Credit", so the stock is accounted for, and it's left out of the cash you expect in the drawer.

Then it's copied to the customer's page the same evening. When they pay, the payment goes in the sales book's cash or transfer total for that day, and on their page.

Do the copying daily. Credit recorded "later" is where most of the leakage happens.

Rules that make credit safe

You choose who gets credit. Keep the list short. Staff can't add to it.

Everyone has a limit. Set it at an amount you could lose without it hurting. When the balance reaches the limit, the answer is "pay something first."

Nothing new while old debt is unpaid past the agreed date. Say this at the start, not during an argument.

The customer sees the page. Show them the entry when they take goods. People dispute debts they never saw written down.

Give a receipt for every payment. A part payment gets a receipt showing the amount paid and the balance left. See how to write a receipt.

Review the summary every month. A debtors book nobody reads is just a neater way of losing money.

When someone won't pay

The book is your evidence and your tool. A customer shown a page with dates, items and their own signature finds it far harder to say "it wasn't that much."

How to ask, what to do when asking doesn't work, and when to let a debt go are in how to collect debts from customers without losing them.