DSO calculator

How DSO is calculated

The standard formula: DSO = (accounts receivable ÷ credit sales in the period) × days in the period. If you're owed $40,000 and invoiced $120,000 over the last quarter, your DSO is (40,000 ÷ 120,000) × 90 = 30 days — on average, a dollar you invoice takes 30 days to arrive.

• Use credit sales, not total sales — cash-up-front revenue never sits in receivables, so including it flatters the number.
• A quarter is the sweet spot for small businesses: a single month swings too much with one big invoice, and a year hides recent deterioration.
• Track the trend, not the snapshot. DSO creeping from 32 to 41 over three quarters is the early warning; any single reading is noise.

What's a good DSO?

There's no universal number — it only means something next to your payment terms. If you invoice Net 30, a DSO near 30 is healthy, the high 30s means clients routinely drift, and 45+ means your terms are effectively fiction. A common rule of thumb: DSO more than 1.5× your terms signals a collections problem, not a client mix problem. The “cash trapped” figure above is the practical translation — money you've earned that's financing your clients' businesses instead of yours.

How to actually lower it

Almost every durable DSO improvement comes from the same three moves: invoice immediately (every day between work-done and invoice-sent is pure DSO), make paying frictionless with a payment link on the invoice, and — the one nobody enjoys — follow up relentlessly and escalate. Our past due email templates cover the escalation ladder, and if you charge late fees, the late fee calculator tells you what an overdue balance is worth.

The follow-up is also the part that automates best: Dueflo chases every overdue QuickBooks invoice with a 6-step escalating sequence, pauses when clients reply, and marks invoices recovered when payment lands — which is how DSO drops without anyone writing another awkward email.