DSO: The Number Every Contractor Should Know

The Corporate Finance Metric Contractors Don't Track

In private equity, when we evaluated a contractor for acquisition, the first financial metric we looked at after EBITDA was DSO — Days Sales Outstanding. It tells you how many days, on average, it takes a company to collect payment after invoicing.

A company with 30-day DSO collects in a month. A company with 90-day DSO takes three months. The difference, on $10M in annual revenue, is roughly $1.6M in cash that's either in your account or tied up in receivables.

Every PE firm, every bank, every CFO in corporate America tracks DSO. Almost no contractor does.

What DSO Looks Like Across the Trades

From analyzing 2.5 million invoices totaling $11.6 billion across 2,200+ contractors, here's the invoice collection picture:

Let that sink in: the median contractor has collected only 70.5% of what they've invoiced. Nearly 30% of invoiced revenue is still outstanding at any given time.

And the bottom quartile? They've collected 43% or less. For a $10M contractor, that's $5.7M in outstanding invoices — money earned, work completed, and cash nowhere to be found.

The Invoice Size Power Law

Not all invoices are equal, and the collection dynamics change dramatically with size:

Classic power law: 0.7% of invoices generate 38% of revenue. Those 16,000 large invoices averaging $275K each are where the real collection risk lives. A single $250K invoice sitting at 90 days overdue has a bigger cash impact than 500 late $200 invoices.

This is why blanket AR follow-up processes don't work. Your $300 residential service invoices need automated reminders. Your $250K commercial invoices need personal attention from day one.

How to Calculate Your DSO

The formula is simple:

DSO = (Accounts Receivable / Revenue) x Number of Days

For a trailing 12-month calculation:

• Pull your current AR balance
• Pull your trailing 12-month revenue
• DSO = (AR / Revenue) x 365

Example:

• Current AR: $1.8M
• Annual revenue: $8M
• DSO = ($1.8M / $8M) x 365 = 82 days

That means, on average, you collect payment 82 days after invoicing.

What's Good?

Most commercial contractors running Net 30 terms should target DSO of 40-50 days. If you're at 70+ days on Net 30 terms, your customers are paying late by 40+ days — and you're financing their business with your cash.

The Outstanding AR Problem

The raw numbers from the dataset on outstanding receivables are staggering:

At the extreme end, the data reveals contractors with tens of millions in outstanding AR. One commercial mechanical contractor invoiced $139M and had $45M outstanding. At the industry-achievable 90% collection rate, that's $31M in recoverable revenue — more than most contractors earn in a year.

Another contractor invoiced $44M and collected only $12M — a 27.4% collection rate with $32M outstanding. That's not a slow-pay problem. That's a business model problem.

But even at the median, the numbers are significant. A typical $8M contractor with the median 70.5% collection rate has $2.4M in outstanding AR. At 88.8% (top decile), that drops to $890K — freeing up $1.5M in cash.

The Three Levers That Control DSO

Lever 1: Billing Speed

How fast you invoice after completing work directly controls how fast you get paid.

From the data: the median contractor invoices 1 day after job completion. The top performers progress-bill before completion (negative billing days — invoicing during the project). The bottom quartile waits 5-10+ days.

Every day of invoicing delay adds a day to DSO. If you invoice 10 days late on Net 30 terms, your effective DSO is 40+ before the customer even starts their payment cycle. Read our full billing speed analysis for the benchmarks.

Lever 2: Payment Terms

Net 30 is standard. But "Net 30" means different things to different customers.

For property management companies and large commercial customers, Net 30 often means "we'll process it in 30 days, then the check takes 10-15 business days." Effective payment: 45-50 days.

For government entities, payment cycles can be 60-90 days regardless of contract terms.

Know your customer DSO. Track payment speed by customer, not just in aggregate. You'll find that 20% of your customers pay in 15 days and 20% take 60+ days. Your DSO is the blended average — but the fix is customer-specific.

Lever 3: Collection Discipline

This is where most contractors lose. They invoice on time, the terms are reasonable, but nobody follows up until the invoice is 45-60 days old.

Best practice from the top-performing contractors in the data:

• Day 7: Automated payment reminder
• Day 21: Personal email to AP contact
• Day 30: Phone call — "Your invoice is now past due"
• Day 45: Escalation to the project manager or property manager
• Day 60: Stop scheduling new work until balance is current

The contractors who collect at 88%+ don't have better customers. They have better follow-up processes. They treat AR like sales — with a pipeline, stages, and accountability.

DSO and Your Borrowing Capacity

Here's something most contractors don't realize: your DSO directly affects your borrowing capacity.

Banks and lenders look at AR quality when sizing a line of credit. AR under 30 days is valued at near face value. AR at 60-90 days is discounted 20-30%. AR over 90 days is often excluded entirely.

A contractor with $2M in AR and 40-day DSO might qualify for a $1.6M line of credit (80% advance rate on clean AR). The same contractor with $2M in AR but 80-day DSO might qualify for $800K — because half their AR is aged and the lender discounts it.

Better DSO = stronger borrowing position = more financial flexibility for growth, equipment purchases, and making payroll during slow months.

When DSO Isn't the Right Metric

Retainage-heavy contractors will always show elevated DSO because 5-10% of every invoice is held for months after project completion. If you do significant commercial work, calculate DSO with and without retainage to see your true collection performance. Read our retainage guide for strategies.

Progress billing contractors may show very low DSO because they invoice before work completes, but their "collection rate" on those invoices might be lower because the work hasn't been certified yet. DSO and collection rate need to be read together.

Rapidly growing contractors will show elevated DSO as a natural consequence of growth. If revenue grew 30% but AR grew 50%, DSO is rising — and that's a cash flow warning sign, not necessarily a collection problem.

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The Bottom Line

DSO is the number that connects your income statement to your bank account. You can have great revenue, strong margins, and still run out of cash if your DSO is 90 days and your payroll is every two weeks.

The median contractor collects 70.5% of invoiced revenue. The top 10% collects 88.8%. On $10M in revenue, that gap is $1.8M in cash — sitting in your customers' accounts instead of yours.

Track the number. Break it down by customer. Fix the worst offenders. Your cash position will reflect it within 60 days.

Q: How does Level help improve DSO? A: We build a real-time AR aging dashboard connected to your QuickBooks, broken down by customer, job, and aging bucket. We calculate DSO weekly (not monthly), flag customers trending past terms, and set up automated follow-up workflows. Most contractors see DSO improve by 10-15 days within the first 90 days. The first audit is free.

Q: What DSO should I target? A: For most $3-30M contractors doing a mix of commercial and service work, target DSO of 40-50 days. Pure residential contractors should target under 30 days. Heavy commercial contractors with retainage may run 55-65 days — that's acceptable if you're tracking retainage separately and collecting the non-retained portion within 35-40 days.

Q: How does DSO relate to my collection rate? A: They measure related but different things. Collection rate tells you how much of what you billed you've collected (cumulative). DSO tells you how quickly you collect (velocity). You can have a high collection rate (95%) but high DSO (75 days) if customers pay eventually but slowly. Both need to be tracked.