Quick Answer
Most trades businesses have no idea which jobs actually make them money. This playbook gives you a five-step framework to calculate true job costs, run an 80/20 profitability audit, identify loss-making work types, restructure your service mix, and implement job-level tracking. The result: less revenue on paper, but far more profit in the bank. I have seen businesses drop 20% of their turnover and double their net margin within six months.
Table of Contents
- The problem: busy but broke
- Step 1: Calculate your true job costs
- Step 2: Run the 80/20 profitability audit
- Step 3: Identify your loss-making work types
- Step 4: Restructure your service mix
- Step 5: Implement job-level tracking
- Tools that make this possible
- Implementation timeline
- What tradespeople are saying
- Recommended videos
- Frequently asked questions
- My verdict
Xero
QuickBooks
Commusoft
Tradify
ServiceM8The problem: busy but broke
There is a pattern I see constantly in trades businesses. The phone is ringing. The diary is full. The team is flat out. And the owner checks the bank account at the end of the month and wonders where the money went.
A 2025 Logic4Training survey found that 47.4% of UK trades businesses cite cash flow and rising costs as their single biggest challenge. Not finding work. Not winning customers. Paying the bills while they are busier than ever.
The root cause is almost always the same. The business takes on every job that comes through the door without knowing which jobs actually make money and which ones quietly bleed it away. Over 50% of home service businesses operate without meaningful profit, according to industry benchmarks. Average net margins for service trades sit between 5% and 7%. Top performers hit 15-25%.
That gap between 5% and 20% is not talent. It is not better tools or a bigger van. It is knowing your numbers at job level, and having the discipline to act on what they tell you.
A heating engineer running 4 service calls per day at an average invoice of £180 turns over £3,600 per week. But if two of those calls cost £177 each to deliver (once you factor in burdened labour, vehicle costs, and overhead), those jobs generate £3 profit each. Drop the two loss-makers and replace them with one properly priced installation, and weekly profit can triple.
Step 1: Calculate your true job costs
Most businesses track materials and labour. That is roughly half the picture. True job cost has four components, and you need all of them before any profitability analysis means anything.
1. Direct materials. Everything you buy for the job: parts, consumables, fixings. Include waste. If you buy a 3-metre length of pipe and only use 2 metres, the job carries the cost of the full length.
2. Burdened labour. Not just what you pay an engineer per hour. Add employer NI (15% from April 2025), pension contributions, holiday pay, sick pay provision, and training costs. A technician on £18/hour actually costs the business £24-27/hour once the burden is applied.
3. Vehicle and travel. Running a £45,000 van costs roughly £650-800 per month in depreciation, insurance, fuel, servicing, and breakdown cover. That is £30-40 per working day. If a call takes 90 minutes including travel, the vehicle cost for that job is £5-8. Small, but it adds up across hundreds of jobs.
4. Overhead allocation. This is where most trades businesses fall down. Rent, insurance, office staff, software subscriptions, accountant fees, phone contracts, marketing spend. Total your monthly overhead and divide by the number of jobs you complete in that month. For a 5-person operation running 300 jobs a month, that might be £25-40 per job.
Small trades businesses typically carry 30-40% overhead as a percentage of gross revenue. If you price jobs using only materials and labour, every job is silently losing money on overhead recovery. Volume makes it worse, not better. You are scaling your losses.
Add all four together. That is what the job actually costs you. Compare it to what you invoiced. The difference is your real margin on that specific job. If it is below 15%, the job barely covered its costs. Below 10%, it lost you money once you account for the inevitable variation and rework.
Step 2: Run the 80/20 profitability audit
Once you can calculate true job cost, the next step is brutally simple. List every job from the last 90 days. Calculate the real margin on each one. Sort from highest to lowest.
The 80/20 rule (Pareto principle) applies to trades businesses with uncomfortable precision. Roughly 80% of your profit will come from around 20% of your jobs. The bottom 20% will actively lose you money. The middle 60% will roughly break even.
When you look at the sorted list, group it into three tiers:
Tier A (top 20%): Your highest-margin jobs. These are the work types, customer segments, and price points where your business thrives. Protect these. Grow these. Build your marketing around attracting more of these.
Tier B (middle 60%): These jobs cover their costs but do not move the needle. Some can be repriced upward. Some can be made more efficient. Some should stay as filler between higher-value work. Do not lose sleep over Tier B, but do not build your business around it either.
Tier C (bottom 20%): These jobs cost you money. Every one you complete makes your business weaker. The goal is to eliminate, reprice, or radically restructure every Tier C job within 90 days.
Your service mix shifts with seasons, pricing changes, and new customers. A quarterly 80/20 audit takes about two hours if your job management software tracks costs properly, and it is the single highest-value exercise a business owner can do. If you are using automated quoting and invoicing, the data is already there.
Step 3: Identify your loss-making work types
The 80/20 audit shows you which individual jobs lost money. Step 3 is about finding the pattern. Loss-making jobs rarely distribute randomly. They cluster around specific work types, customer segments, or pricing models.
Here are the five most common loss-makers in UK trades businesses:
Small reactive callouts without a minimum charge. A single socket replacement or dripping tap that takes 30 minutes on site but 45 minutes in travel and 20 minutes in admin. Without a minimum charge of £80-120, these jobs cannot cover their true cost.
Fixed-price contracts inherited from years ago. That maintenance contract you quoted at £4,500 in 2022 has not been repriced, but your labour costs have risen 12% and material costs 18%. It now costs you £5,200 to deliver. You are paying your client to work for them.
Scope-creep jobs where you absorbed extras. The rewire that started as first fix only but somehow included making good, painting, and three return visits. Every unpriced variation is profit walking out the door.
Distance jobs in low-density areas. A boiler service 40 minutes away might look like a £120 job, but the 80 minutes of travel pushes vehicle and labour cost to the point where your margin is single digits.
Customers who pay late and dispute invoices. The cost of chasing payment, managing disputes, and carrying the cash flow gap is real. A 60-day payment delay on a £3,000 job costs you roughly £40-60 in working capital interest alone, plus the admin hours.
Loss-making jobs are almost always the ones that cause the most stress. Difficult customers, unreasonable expectations, constant phone calls, disputes. When you drop this work, you do not just improve your margins. You get your evenings back.
Step 4: Restructure your service mix
Identifying loss-making work is the analysis. This step is the action. You have three options for every Tier C job type:
Option 1: Reprice. If the work is profitable at a higher rate, raise your price. Introduce minimum charges for small jobs (£80-120 is standard in 2026 for most trades). Add callout fees. Apply a proper overhead recovery markup. Some customers will leave. That is the point. The ones who stay are now profitable.
Option 2: Restructure. Some jobs lose money because of how you deliver them, not what you charge. Batch small jobs by geography so you do four callouts in one area instead of driving across town between each one. Standardise materials so you carry common parts on the van and eliminate supplier trips. Cut the admin by using job management software that automates invoicing, scheduling, and customer communication.
Option 3: Drop. Some work types are simply wrong for your business at any price. If you are a 10-person heating company, single tap washer replacements are not your market, regardless of what you charge. Refer them to a sole trader who specialises in small domestic work. Focus your capacity on the installations, maintenance contracts, and commercial work where your margins are strongest.
This is where most business owners freeze. Turning away revenue feels wrong. Every instinct says take the work. But revenue is vanity, profit is sanity. A business that turns over £400,000 with a 5% net margin makes £20,000. A business that turns over £320,000 with a 15% net margin makes £48,000. Less work. More money. Less stress.
If you want to build predictable income that replaces reactive callouts, a planned maintenance contract programme is one of the most effective ways to fill the gap left by dropped Tier C work.
| Metric | Before (take every job) | After (optimised mix) |
|---|---|---|
| Annual turnover | £400,000 | £320,000 |
| Net margin | 5% | 15% |
| Net profit | £20,000 | £48,000 |
| Jobs per month | 310 | 220 |
| Avg margin per job | £5.40 | £18.20 |
| Late payment disputes | 8-12/month | 1-2/month |
| Weekend stress calls | Regular | Rare |
Step 5: Implement job-level tracking
The framework only works if you keep measuring. A one-off audit is useful. A monthly review is transformational. Here is the minimum data you need to capture on every job:
Time on site (actual, not estimated). Travel time. Materials used (with cost). Any extras or variations. Invoice amount. Payment date.
From those six data points, you can calculate true margin on every job. Most modern job management platforms do this automatically if you set them up properly. Commusoft, Tradify, ServiceM8, and Fergus all have job costing features built in. The key is actually using them, which means your team needs to log time accurately and record materials as they use them, not from memory at the end of the week.
If your team resists logging time, it is usually because the process is clunky. A mobile app that takes 30 seconds to clock in and out of a job gets used. A paper timesheet that needs completing at the end of the day does not. Pick software your team will actually use. See our guide to digital transformation for HVAC businesses for a practical example.
Set a monthly review cadence. Every month, pull a report showing margin by job type, by customer, and by engineer. Look for drift. If a work type that was profitable three months ago is now marginal, something has changed, either your costs went up or your pricing did not keep pace.
The real power comes when your job management platform feeds directly into Xero or QuickBooks. Automated invoicing eliminates the gap between completing a job and getting paid, and it means your profitability data is always current. Our software stack guide covers exact costs and integrations.
Tools that make this possible
You do not need expensive enterprise software to run this framework. Here are the tools that matter, with realistic UK pricing:
Xero (from £15/month for Starter, £33/month for Growing). Cloud accounting with project tracking, bank feeds, and automatic reconciliation. Integrates with most job management platforms. The Growing plan supports unlimited invoices and multi-currency, which covers most trades businesses up to 20 employees.
QuickBooks (from £12/month for Simple Start, £22/month for Essentials). Similar to Xero with slightly different strengths. Better built-in job costing reports. Slightly less popular with UK accountants than Xero, but perfectly capable.
Commusoft (pricing on request, typically £30-50/user/month). Purpose-built for field service businesses. Job costing, scheduling, invoicing, and customer communication in one platform. The job profitability reports are excellent if your team logs data properly.
Tradify (from £29/user/month). Designed specifically for trade businesses. Quoting, job management, timesheets, and invoicing. Integrates with Xero. Good for smaller teams of 1-10 people.
ServiceM8 (from £23/month for Starter). Strong on mobile, which means better field data capture. Job dispatch, quoting, invoicing, and online booking. Best suited to sole traders and small teams.
The minimum viable setup is an accounting platform (Xero or QuickBooks) plus a job management tool that integrates with it. Budget £50-80/month total for a sole trader, £200-400/month for a 5-10 person team.
Implementation timeline
Gather your data
Export the last 90 days of jobs from your accounting or job management software. You need invoice amount, materials cost, and labour hours for each job. If you do not have this data, start capturing it now and run the audit after 90 days of clean data.
Calculate overhead rate
Total your fixed monthly costs (rent, insurance, vehicles, software, admin salaries, accountant, phones, marketing). Divide by monthly job count. This is your per-job overhead allocation. Apply it to every job in your 90-day dataset.
Run the 80/20 audit
Sort jobs by real margin. Identify Tier A (top 20%), Tier B (middle 60%), and Tier C (bottom 20%). Look for patterns in the Tier C jobs: work type, customer type, geography, pricing model.
Decision time
For each Tier C pattern, decide: reprice, restructure, or drop. Communicate price changes to existing customers with 30 days notice. Set up minimum charges and callout fees. Brief your team on which work types you are no longer accepting.
Implement and monitor
Enforce the new pricing and service mix. Track job margins weekly for the first month. Expect a 10-20% drop in job volume. Watch your net margin climb. Run a second 80/20 audit at the 90-day mark to measure progress.
What tradespeople are saying
Recommended videos
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5 Best Job Costing Software 2025
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Frequently asked questions
Yes, some. That is the point. The customers who leave over a fair price increase were costing you money. The ones who stay are now profitable. In my experience, businesses lose 10-15% of customers after a reprice and end up with higher net profit within three months.
Start tracking now. Get your team logging time, materials, and travel on every job for the next 90 days. You cannot optimise what you cannot measure. In the meantime, pick your five biggest jobs from last month and calculate true cost manually. Even that rough audit will reveal surprises.
Show them the numbers. Engineers are smart people. When they see that four loss-making callouts could be replaced by one profitable installation, they get it. Frame it as working smarter, doing fewer stressful jobs for more money. Most engineers prefer quality work over a punishing schedule of small reactive jobs.
Aim for 10-15% net as a baseline, 15-25% for top performers. The average sits around 5-7%, which is barely survivable. If you are below 10%, there is almost certainly Tier C work dragging your numbers down.
It matters more for sole traders. You have one pair of hands and a fixed number of hours per week. Every hour spent on an unprofitable job is an hour you cannot spend on one that pays properly. A sole trader who works 45 hours a week and eliminates 8 hours of loss-making work can earn more from 37 hours.
My verdict
I ran a heating and plumbing business for years before starting TrainAR. The single most impactful decision I made was not hiring another engineer or buying a better van. It was sitting down with a spreadsheet, working out which jobs were costing me money, and stopping doing them. Turnover dropped. Profit went up by quite some margin. Stress went down. The framework in this playbook is exactly the process I followed. It works. But it only works if you commit to measuring at job level and acting on what the numbers tell you, even when that means saying no to a paying customer.
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