Most underpriced plumbing and heating jobs aren’t underpriced by accident. They’re priced against what a competitor might charge, rather than what the job actually costs to deliver profitably. How to price jobs profitably starts with a different question entirely: not “what should I charge,” but “what does this job genuinely cost me, and what needs to sit on top of that.”
This guide covers exactly how to build a quote from real numbers, so pricing protects your margin instead of quietly eroding it, job after job.
At a Glance
| Best for | Sole traders and small plumbing, heating, gas, drainage or HVAC businesses reviewing or building their pricing from scratch |
| Difficulty | Moderate, mostly arithmetic and honest cost tracking, not complex financial modelling |
| Time required | 2–3 hours to build a proper hourly rate and pricing structure |
| Expected business impact | Every job contributes genuine profit, rather than some jobs quietly running at a loss without you realising |
How to Calculate Labour Costs for a Job
Labour cost is more than your hourly wage. It needs to include employer National Insurance, holiday pay, pension contributions, and any time spent on admin, travel and quoting that isn’t directly billable. A job that only accounts for your take-home pay per hour will always underprice the true cost of delivering it.
What to Include in Your True Labour Cost
- Your own or your employee’s gross wage, including National Insurance and pension contributions
- Paid holiday and any sick pay commitments
- Non-billable time: quoting, admin, travel between jobs
- Training, certifications, and ongoing CPD costs
How to Calculate Your Hourly Rate
Rather than guessing at what a reasonable rate might be, build your rate from your own numbers.
- Add up your total annual running costs: wages, overheads, insurance, vehicle, tools and materials margin
- Work out your realistic billable hours per year, not 40 hours a week for 52 weeks, but hours actually spent on paid work after holiday, admin and travel
- Divide total annual costs by billable hours to find your break-even rate
- Add your target profit margin on top of the break-even figure
A rate built this way reflects what your business actually needs to earn, not what a competitor happens to be charging this month.
How to Include Overheads in Job Pricing
Overheads are the costs that exist whether or not you’re on a job, insurance, van finance and fuel, tools, software subscriptions, and business admin. If they aren’t built into every quote, they get silently absorbed by profit instead, which is one of the most common reasons a busy business still struggles for cash.
A practical approach: total your monthly overheads, divide by your realistic billable hours that month, and add that figure to every job alongside labour and materials. This way, overheads are recovered consistently rather than hoped for at the end of the year.
Fixed Price vs Day Rate: Choosing the Right Model
| Pricing model | Best suited to |
| Hourly rate | Diagnostic work or jobs with genuinely unknown scope |
| Fixed price | Jobs with clearly defined scope, such as a boiler swap or toilet replacement |
| Day rate | Larger jobs spanning most or all of a working day, such as a bathroom installation |
Fixed pricing gives customers certainty and protects your margin on well-understood jobs. Hourly pricing protects you on jobs where the scope genuinely can’t be known until you’re on site. Choosing the wrong model for the job- fixed pricing for something unpredictable, or hourly pricing for something routine- is a common source of lost margin.
How to Create a Profitable Quote
A properly built quote adds these elements in order, rather than picking one final number from instinct:
- Materials cost, including a fair markup for sourcing and handling
- Labour cost, using your calculated hourly rate, not a rounded guess
- Overhead recovery, spread proportionally across the job
- Profit margin, added deliberately, not left to whatever’s left over
- VAT, if applicable, sole traders must register once taxable turnover exceeds the current VAT registration threshold, and VAT should be shown clearly on the quote, not buried in the total
How to Calculate Profit Margin on a Job
Profit margin is what’s left after materials, labour and overheads are covered, and it should be added as a deliberate percentage, not whatever remains once a round-number quote has been sent. A common approach is to add a target margin of 15–25% on top of your full cost base, adjusted for job complexity and risk. Reviewing actual costs against the original quote once a job is finished is the only reliable way to confirm your margin assumptions are actually holding up in practice.
Common Mistakes When Pricing Jobs
Pricing against competitors instead of your own costs. A competitor’s quote tells you nothing about whether that price actually covers their overheads, let alone yours.
Forgetting non-billable time. Quoting, admin, and travel all cost real hours that need recovering somewhere in your pricing.
Treating overheads as an afterthought. If overheads aren’t built into every quote, they’re being paid for out of profit without you noticing.
Using hourly pricing on well-defined jobs. This creates uncertainty for the customer and often ends up undercharging for genuinely routine work.
Never reviewing actual costs against the quote. Without comparing estimated to actual costs after the job, pricing mistakes repeat indefinitely.
Key Takeaways
- Build your hourly rate from your actual costs and realistic billable hours, not from what competitors charge
- Include employer National Insurance, holidays, pensions and non-billable time in your true labour cost
- Recover overheads on every job by spreading monthly costs across billable hours
- Match the pricing model to the job: fixed price for known scope, hourly for genuine uncertainty
- Add profit margin deliberately as a percentage, not as whatever’s left over
- Show VAT clearly on quotes once registered, rather than folding it into a single total
- Review actual job costs against your original quote regularly to confirm your pricing still holds up
What to Do Next
Profitable pricing protects everything else you’re building in the business, from cash flow to genuine growth. If your pricing feels solid but your enquiry volume doesn’t match the work you want to be doing, book a free Digital Growth Audit, and we’ll show you where the gap is.
FAQs
1. How do I calculate my hourly rate as a plumber or heating engineer?
Add up your total annual running costs, including wages, overheads, insurance and vehicle costs, then divide by your realistic billable hours for the year. This gives you a break-even rate, to which you then add your target profit margin.
2. Should I quote a fixed price or an hourly rate?
Fixed pricing works best for jobs with a clearly defined scope, like a toilet replacement or boiler swap. Hourly pricing suits diagnostic or unpredictable work where the scope genuinely can’t be known before you start.
3. How much profit margin should I add to a job?
A common starting point is 15–25% on top of your full cost base, adjusted for the complexity and risk of the specific job. The right figure depends on your overheads and how competitive your local market is.
4. What should be included in job overheads?
Insurance, van finance and fuel, tools, software subscriptions, and general business admin all count as overheads, since they exist whether or not you’re actively on a job.
5. When do I need to charge VAT on my quotes?
Once your taxable turnover exceeds the current VAT registration threshold, you must register and charge VAT, which should be shown as a clear, separate line on every quote rather than built into a single final figure.
