Reading a P&L Statement for a Service Business
Why this matters
Most small field-service operators can't read their own P&L. The CPA hands it over at year-end + the owner stares at it for 90 seconds + files it away. That gap is the #1 reason contractors run out of cash in year 3. The P&L isn't accounting trivia - it's the operating dashboard that tells you whether the business actually makes money, where the leaks are, + what to fix next.
The five sections of every P&L
A Profit & Loss statement (also called Income Statement) breaks into:
- Revenue (top line)
- Cost of Goods Sold (COGS) - direct cost of delivering the service
- Gross Profit = Revenue - COGS
- Operating Expenses - everything else to run the business
- Net Profit = Gross Profit - Operating Expenses
These five numbers tell the whole story. Everything else is sub-detail.
Revenue (top line)
What you billed customers in the period. Cash basis = when paid; accrual basis = when invoiced. Service businesses usually run accrual for the accurate picture, cash for tax purposes.
Break revenue into service-line buckets:
- Recurring maintenance (highest-margin)
- Repairs (mid-margin)
- Installs / replacements (volume-driver)
- Emergency / after-hours (premium)
- Membership / club dues (recurring)
The mix matters more than the total. Two shops with the same top line have different economics if one is 80% installs + 20% maintenance and the other is 40% recurring + 60% repairs.
Cost of Goods Sold (COGS) - the trade-specific line
In a service business, COGS includes everything directly tied to delivering the job:
- Direct labor: technician wages + payroll taxes + workers comp on hours billed to jobs (NOT office staff)
- Materials: parts, supplies, sub-contracted work
- Vehicle costs allocated to jobs: fuel + maintenance (some operators put these in OpEx; the IRS allows either; pick one + stay consistent)
- Subcontractor payments: when you hire out portions of work
- Job-specific permits + fees
What's NOT in COGS:
- Office staff wages
- Owner's salary (typically OpEx)
- Marketing
- Office rent
- General insurance
- Software + tech subscriptions
Gross Profit + Gross Margin
Gross Profit = Revenue - COGS
Gross Margin % = Gross Profit ÷ Revenue × 100
Healthy gross margin by trade, computed on the full COGS line above, with labor burden and allocated vehicle cost included:
- HVAC residential: 35 - 50%
- Plumbing residential: 35 - 50%
- Electrical residential: 35 - 50%
- Roofing residential: 25 - 40%
- Cleaning residential: 40 - 60%
- Pool service: 40 - 60%
- Pest control: 50 - 70%
- Lawn care: 35 - 55%
- Tree service: 25 - 40%
Below the trade benchmark = you're either underpricing OR overspending on direct labor + materials.
These bands read lower than the single cross-trade figure in Financial KPIs for a Service Business, which is stated on the job basis and carries no payroll tax, workers comp, allocated vehicle cost or permits above the line. Neither is wrong; they are different lines. Measure your own margin against whichever basis your chart of accounts actually uses, and say which one you used when you quote the number to anybody else.
Operating Expenses (OpEx) - the rest
Everything to run the business that isn't a direct job cost:
- Office salaries + owner pay: dispatcher, CSR, bookkeeper, owner
- Marketing: ads, lead gen, referral payouts
- Office rent: shop, warehouse, office
- Insurance (non-WC): GL, vehicle, umbrella, EPLI
- Vehicle leases / payments: if not allocated to COGS
- Office vehicle fuel + maintenance: non-billable miles
- Software subscriptions: CRM, QuickBooks, dispatch
- Phone + internet
- Office supplies
- Continuing education + training
- Professional services: accounting, legal, consulting
- Depreciation: vehicles, equipment, computers
- Interest on loans
Net Profit + Net Margin
Net Profit = Gross Profit - Operating Expenses
Net Margin % = Net Profit ÷ Revenue × 100
Healthy net margin for residential service business: 8 - 18% pre-tax. Take that as the span of what gets published rather than one agreed number. The floor sits consistently at about 8; the ceiling is where sources part company, quoted anywhere from 15 to 18, so the top third of the band is the contested part. Unlike the gross-margin bands above, this is not a basis difference: net margin is the bottom of the same statement however you split COGS and OpEx, so the same quantity is simply being reported with different ceilings. Financial KPIs for a Service Business quotes this band and points back here for it. Trade-specific cards publish their own and some sit above it; a specialty line is not the cross-trade figure.
Below 8%: structural problem; review pricing + labor cost + overhead. Between 15 and 18%: real, but read the next section before you bank it. An owner who has not taken a market salary out of OpEx is reporting part of that salary as profit, which is the most common reason a shop reads high in the band. Above 18%: either an exceptional operator OR pricing premium OR underinvesting in growth.
The number most owners get wrong: their own pay
The "owner's salary" question:
- If owner works in the field: their billable hours' labor cost belongs in COGS (just like any tech)
- If owner runs the business: their salary belongs in OpEx
- If owner does both: split it; reasonable allocation based on time
Pretax net profit AFTER paying yourself a market salary is the real number. Owners who don't pay themselves + show 20% "profit" are kidding themselves - that profit IS their compensation + the business isn't earning what they think.
Reading the P&L month-over-month
Monthly comparison reveals trends:
- Revenue declining 3+ months: marketing OR sales OR seasonality issue
- COGS % rising 2+ months: material costs up OR labor over-allocated OR pricing eroded
- OpEx growing faster than revenue: scope creep OR poor cost discipline
- Net margin declining: one of the above
The pattern matters more than any single month.
Comparing to industry benchmarks
Industry surveys (PHCC for plumbing/heating, IEC for electrical, ASEC for HVAC, etc.) publish annual cost-of-doing-business data. Compare your P&L line items to industry medians:
- Direct labor as % of revenue
- Materials as % of revenue
- Marketing as % of revenue
- Total OpEx as % of revenue
This calibration tells you where you're above or below peers. Numbers way above peers = leak. Numbers way below = either lean operation OR underspending (e.g., 0% marketing = stalled growth).
The single highest-value habit for a service-business owner is the MONTHLY P&L REVIEW - 30 minutes on the 5th - 10th of the following month, with your bookkeeper. Read every line. Compare to last month + same month last year. Flag what changed. Most owners avoid this because they don't understand the document; the act of doing it every month + asking the bookkeeper "what is this" teaches you the document. After 6 months, you'll read it fluently + catch issues before they sink the business.
Cash vs accrual (the basics)
- Cash basis: revenue when paid; expenses when paid
- Accrual basis: revenue when earned (invoiced); expenses when incurred (billed)
Most service businesses operate on accrual for management + cash for tax. Your bookkeeper or accountant chooses; you should know which.
Accrual reveals lag between work + payment - important for collections + cash flow. Cash hides this.
What a P&L DOESN'T tell you
The P&L is profit. The cash flow statement is cash. They're different:
- A profitable business can run out of cash (if customers don't pay fast enough)
- A money-losing business can have cash on hand (financed loss, prepaid revenue)
Owner needs to read BOTH. P&L tells you if you're earning; cash flow tells you if you can pay the rent next week.
References
- "Profit First" by Mike Michalowicz (service business application)
- IRS Publication 334, Tax Guide for Small Business (business expenses + cost of goods sold; basis for the vehicle-cost classification note above)
- PHCC, NECA, ACCA cost-of-doing-business surveys
- QuickBooks + Xero help documentation
- Manuall internal: Financial KPIs for a Service Business, Weekly Cash Flow Forecast SOP