Debtors Days Calculator (DSO / Collection Period)

Calculate Average Collection Period for Credit Sales

Debtors Days (DSO) Formula

Formula

\[ \text{Debtors Days} = \left( \frac{\text{Trade Receivables}}{\text{Annual Credit Sales}} \right) \times D \]

Where:

$TR$ — trade receivables: the total amount owed by customers for credit sales (currency)
$CS$ — annual credit sales: total sales made on credit during the year (currency)
$D$ — number of days in the year, typically 365 or 360

The formula expresses, in days, the average time it takes a business to collect payment from customers after a credit sale. It is also known as days sales outstanding (DSO) or the average collection period.

Debtors Days – Calculation Example

Example: a company has $$25{,}000$ in trade receivables and $$150{,}000$ in annual credit sales. Using a 365-day year:

\[ \text{Debtors Days} = \frac{25{,}000}{150{,}000} \times 365 = 0.1667 \times 365 \approx 60.8 \text{ days} \]

Result: it takes the company about 60.8 days on average to collect payment from its customers.

How to Use the Debtors Days Calculator

Enter the Trade Receivables — the total outstanding credit currently owed to you by customers. You can find this as "accounts receivable" on your balance sheet.
Enter the Annual Credit Sales — the total revenue from sales made on credit over the year (not cash sales).
Set the Days in Year — use 365 for a standard year or 360 if your financial reporting convention requires it.
Read the result: the Debtors Days (DSO) field shows the average number of days it takes to collect payment.

What Are Debtors Days?

Debtors days, also called days sales outstanding (DSO) or the average collection period, measures how quickly a business converts credit sales into cash. Whenever you sell on credit, the amount owed sits in accounts receivable until the customer pays. Debtors days tells you, on average, how long that money stays outstanding.

The metric is a core part of working capital analysis. A lower value means customers pay faster, cash flows into the business sooner, and less capital is tied up in receivables. A higher value signals slower collections — money you have earned on paper is not yet available to pay suppliers, staff, or loans. Debtors days is often analyzed alongside creditors days and inventory days to estimate the cash conversion cycle.

There is no single "good" number, because collection periods vary widely by industry. Retail businesses typically collect within days, while construction or B2B manufacturers may operate on 60- to 90-day terms. The most useful comparisons are against your own payment terms (if you offer 30-day terms but debtors days is 55, customers are paying late), your own historical trend, and industry benchmarks.

To dig deeper into your company's financial health, debtors days can be paired with liquidity and leverage metrics such as the Debt Coverage Ratio, the Interest Coverage Ratio, or the Debt to Equity Ratio.

Interpreting the Result

Below 30 days: collections are fast; your credit policy is working well and cash is arriving quickly.
30–60 days: typical for many B2B businesses; compare against your stated payment terms to spot slippage.
Above 60–90 days: customers are slow to pay; consider tighter credit checks, earlier invoicing, discounts for prompt payment, or a more active collection process.
Rising trend over months: a warning sign — the same customers are taking longer to pay, which strains cash flow even if sales are growing.

Assumptions and Limitations

The calculation assumes credit sales are spread evenly across the year. If your business is seasonal, the ratio can be misleading: a high receivables balance measured just after a peak sales month will inflate debtors days, while a quiet month will understate it. For seasonal businesses, it is more accurate to use receivables divided by average daily credit sales over the recent period rather than the full year.

Note that the formula should use credit sales only. Including cash sales in the denominator understates the collection period, because cash sales are collected instantly and add no receivables. If you cannot separate cash and credit sales, using total sales gives an approximation — but be consistent so trends remain comparable.

A single number tells you little; track debtors days month by month, compare it with the payment terms you actually offer, and benchmark it against similar companies. Consistency in the days-in-year convention (365 vs. 360) matters too — pick one and stick with it across periods, or your trend will jump without any real change in collections.

Quick Reference Table

Trade Receivables	Annual Credit Sales	Days in Year	Debtors Days
$10,000	$100,000	365	36.5 days
$25,000	$150,000	365	60.8 days
$40,000	$200,000	365	73.0 days
$50,000	$500,000	365	36.5 days

The table shows how the same receivables balance can mean very different collection speeds depending on sales volume — always read debtors days relative to the size of your credit sales.

Frequently Asked Questions

How do I calculate debtors days by hand?

Divide trade receivables by annual credit sales, then multiply by the number of days in the year: $ \text{Debtors Days} = \frac{TR}{CS} \times D $. For example, receivables of $$40{,}000$ and credit sales of $$200{,}000$ give $ \frac{40{,}000}{200{,}000} \times 365 = 73 $ days. You only need a calculator and two figures from your financial statements.

What is a good number of debtors days?

There is no universal target — it depends on your payment terms and industry. Retailers may collect in under 15 days, while construction or manufacturing firms often run 60–90 days. A practical rule: debtors days should be close to the credit terms you offer. If you give 30-day terms but the figure is 50+, customers are paying late and your cash flow is suffering.

Should I use 365 or 360 days in the formula?

Use 365 for a standard calendar year; 360 is common in banking and some accounting conventions (a "30/360" year). Both are acceptable, but switching between them distorts comparisons — 360 days understates the result by about 1.4% versus 365. Pick one convention and apply it consistently across all periods you compare, whether tracking trends or benchmarking against competitors.

Why does using total sales instead of credit sales give a wrong answer?

Cash sales generate no receivables, so including them in the denominator shrinks the ratio and makes collections look faster than they really are. If cash sales are 50% of revenue, your debtors days could be roughly halved. If you cannot separate the two, use total sales as an approximation — but do it every period, so the trend stays meaningful even if the absolute value is understated.

Can debtors days be negative or zero?

Zero is possible when receivables are zero — meaning all customers have paid, which is normal right after collections or in cash-only businesses. Negative debtors days cannot occur from the standard formula, since receivables cannot be negative. However, if customers pay in advance, the related metric "days payable outstanding" for suppliers is the mirror image: prepaid sales show up elsewhere, not as negative receivables.

How is debtors days different from the average collection period and DSO?

They are three names for the same metric. Debtors days, days sales outstanding (DSO), and average collection period all measure how many days pass between a credit sale and collecting the cash. The terms differ mainly by region and context: "debtors days" is common in UK and Commonwealth accounting, while "DSO" dominates in US finance and credit management reporting.

How does debtors days affect the cash conversion cycle?

Debtors days is one of three components of the cash conversion cycle: $ \text{CCC} = \text{Inventory Days} + \text{Debtors Days} - \text{Creditors Days} $. It shows how long your cash is tied up from buying inventory to receiving customer payments. Reducing debtors days shortens the cycle and frees working capital, but beware — stretching supplier payments (higher creditors days) instead only shifts the problem onto others.

Debtors Days Calculator