How to Track Project Profitability in Your Accounting Software

Your business is profitable — at least, that's what your P&L says. But is it really? And more importantly, are all your projects actually making money, or are you quietly subsidising work that looks good on paper but drains cash when you zoom in?

Tracking project profitability in your accounting software is how you answer these questions. It's the difference between knowing you made £50,000 profit and knowing which projects made that profit and which ones barely broke even. Get it right, and you'll price better, allocate your team to the work that matters, and stop bleeding money on projects that shouldn't exist.

This practice—sometimes called job costing—means assigning every pound of revenue and every penny of cost to individual projects, clients, or jobs. If you're in construction, the HMRC Construction Industry Scheme essentially requires it (and our construction accounting guide walks you through the specifics). But whether you're a plumber, an agency, a consulting firm, or a services business of any kind, the principle is the same: hidden loss-making projects are a silent profit killer.

Why project-level profitability actually matters

Overall profit masks the problems

Here's the uncomfortable truth: a business that looks profitable overall can be harbouring deeply unprofitable projects. Run ten projects, seven at 40% margin and three at -10% margin? Your P&L shows healthy profit. Your gut might tell you something's wrong—and it's right to.

This is where many small-business owners get stuck. You see the bottom line is positive, so you assume the business is working. You don't realise you're pouring resources into work that actively loses money because you're not asking which projects are dragging you down.

You can't price accurately without it

When you don't know the actual cost of delivering a project, you guess at pricing. You remember the last project that was "similar" and charge the same rate. Then it takes 40% longer because you missed something, and suddenly that project is unprofitable.

Good pricing is built on historical data. Show me your last ten projects and their actual costs, and I'll show you how much you've been undercharging. Most small businesses have left significant money on the table in the last year just from bad estimates.

Resource allocation becomes obvious

Project profitability data shows you where your best people should actually be working. If your senior team spends most of their time on low-margin projects while graduates handle the high-value work, there's an efficiency gap you can close.

This is not about blame. It's about realising you have capacity to move around.

Client profitability (the quiet revelation)

When you aggregate projects by client, a pattern usually emerges: a small number of clients account for most of your profit, while others barely break even (or lose money). Harvard Business Review research has long shown this pattern in customer profitability—and it's just as true in service businesses.

This shapes your decisions about which relationships to invest in, which to renegotiate, and which to gently hand over to a competitor who might value them more.

Setting up project tracking in your accounting software

Create projects or cost centres

Most accounting software—whether you're moving from spreadsheets or starting fresh—lets you create projects or cost centres. Each one should map to a piece of work you want to isolate and measure independently:

A client engagement
A construction job
A consulting project
A product development sprint
An event you're running

The more discipline you bring to project creation, the more useful your data becomes later.

Define your cost buckets before you start

Before you tag a single invoice, decide what cost categories matter for your business. The obvious ones:

Direct labour — Time your team spends on the project
Subcontractors — External freelancers or agencies
Materials — Physical goods consumed
Travel and expenses — Flights, hotels, mileage, meals
Tools and software — Project-specific software subscriptions or one-off licences
Overhead allocation — Your share of rent, utilities, admin time, accountant fees

Don't try to track 20 categories. Start with six. You can refine later.

Assign revenue correctly

Every invoice related to a project gets tagged to that project. If an invoice spans multiple projects, split it. This is tedious (which is why software matters—it should handle this automatically), but it's non-negotiable for accuracy.

Assign costs—this is where the discipline lives

Every expense that touches a project gets tagged. This includes:

Purchase invoices from suppliers and subcontractors
Expense claims from your team (they need to specify the project)
Time entries (covered below)

The weak point for most businesses is indirect costs. It's easy to remember to log the £2,000 subcontractor invoice. It's harder to remember that you spent 12 hours in project meetings, or that your accountant spent 6 hours setting up the job in your system.

Handle overhead: pick a method and stick to it

Rent, insurance, admin salaries—these costs benefit all projects, but you can't directly tie them to individual ones. You have options:

As a percentage of revenue — If Project A is 20% of your revenue, it takes 20% of overheads
As a percentage of direct costs — Same idea, but based on your direct cost footprint
Built into hourly rates — Factor overhead into what you charge per hour
Leave at business level — Track only direct costs per project; handle overhead separately

Pick one method. Use it consistently. Wrong-but-consistent beats right-but-chaotic. (If you're preparing for a meeting with your accountant, they'll want to see how you've allocated overheads, so pick a defensible method.)

Key metrics for project profitability

Gross margin: the signal

Gross margin is revenue minus direct costs. It shows what each project contributes before overheads are considered.

Gross margin % = (Revenue − Direct costs) ÷ Revenue × 100

A project with £50,000 revenue and £30,000 direct costs has a 40% gross margin. If your target is 50% and this project lands at 40%, that's useful information.

Net margin: the reality check

Net margin includes your allocated overheads. This is the true profit each project generates.

Net margin % = (Revenue − Direct costs − Allocated overheads) ÷ Revenue × 100

Gross margin is encouraging. Net margin is honest.

Revenue per hour (for time-based work)

If you sell time, this metric matters enormously. Divide total project revenue by total hours worked.

Revenue per hour = Total project revenue ÷ Total hours

This is often shocking. You might bill £150/hour, but once you factor in unbilled time, project management, scope creep, and internal reviews, you're actually earning £95/hour. That gap is where your margins evaporate.

Budget vs. actual

Compare what you estimated to what you actually spent. This feeds back into your next estimate. A consistent pattern (always running 15% over budget) means your estimation process needs calibration.

Common pitfalls that kill project profitability tracking

Not tracking time

For service businesses, labour is often your biggest cost. If you don't track how much time your team spends on each project, your profitability numbers are fiction. Even rough time tracking beats none.

Forgetting the invisible hours

People are good at logging billable work hours. They're terrible at logging the meetings, emails, internal reviews, admin, and travel time that also belong to the project. That's your margin erosion—right there.

Many small businesses find that tracking all expenses—not just direct ones—is the breakthrough moment in understanding true project profitability.

Changing your allocation method mid-stream

If you allocate overhead one way for Project A and differently for Project B, your comparisons are useless. Pick a method and lock it in.

Waiting until project completion to look at the numbers

By then, it's too late. You can't fix an unprofitable project that's already finished. Monitor costs and margins during the project so you can take action—renegotiate scope, tighten resources, escalate issues—before it becomes a loss-maker.

Scope creep invisibility

When clients ask for "just a bit more," and you do it without updating the invoice, that's profit erosion. The work is real; the cost is real. Log it, measure it, and have a conversation about change orders.

Using project data to actually improve things

Pricing adjustments built on history

If your projects consistently land below your target margin, your pricing strategy is wrong. Use actual project data—not guesses—to build better estimates that account for all costs, including the ones you've been overlooking.

Go/no-go decisions

Before accepting a new project, estimate its profitability based on historical similar work. If the projected margin is below your threshold, either renegotiate the price or decline it. This sounds obvious. Most small businesses don't do it.

Team performance and training

Project data combined with time tracking reveals who delivers efficiently and who doesn't. This isn't about punishment—it's about where training, better tools, or process improvements could help.

Client segmentation

Rank your clients by profitability. You'll often find that 20% of your clients generate 80% of your profit. This should directly influence where you spend your time and energy.

Choosing software that actually supports this

Your accounting software needs to make project tracking simple, not a chore. Look for:

Project or job code assignment on invoices, bills, and expenses
Time tracking integration (built-in or connected)
Project-level reporting—profit and loss by project, budget vs. actual
Dashboard views that show project performance at a glance

Relentify's accounting module includes project tracking with integrated time recording, so you can assign revenue and costs to individual projects and see profitability at the project and client level—without switching between three different tools.

Frequently Asked Questions

How do I track time if my team uses different tools? Most accounting software integrates with time-tracking tools, or has basic time recording built in. If your team is spread across tools, consolidate into one—even a simple one. The overhead of manually entering time is worth the clarity you get.

Do I need to track overhead for small projects? Yes. Overhead is real, even on small projects. The question is whether you allocate it proportionally or at a flat rate. Without it, you'll underestimate your true cost, even on projects that look profitable at the gross margin level.

What if a project is unprofitable mid-way through? First, understand why. Is it scope creep? Bad estimation? Inefficiency? Then decide: can you renegotiate with the client, tighten execution, or write off the loss as a lesson? Do this for the next similar project, not to punish yourself retroactively.

How detailed should my cost categories be? Start with five to seven categories. More than that and you'll spend more time categorising expenses than you'll learn from the data. As you grow, you can refine.

Should I track all my projects or just the big ones? Track all of them. You'll be surprised which small projects are highly profitable and which big ones barely break even. Your intuition about project profitability is probably wrong.

What's a "good" project margin? That depends on your industry and business model. Service firms often target 40–60% gross margin. Construction might be 20–35%. Consulting can be 50–70%. Know your target, then use project data to work toward it.

How often should I review project profitability? Monthly, at minimum. If you're project-based, you might review weekly or after each project closes. The more frequently you look, the faster you improve.

Can I use spreadsheets instead of accounting software for this? You can, but you'll spend an hour a week maintaining it. Accounting software handles the tagging and reporting automatically. For a small business, that time back is worth the subscription price.

The path from "I'm profitable overall" to "I know exactly which projects make money and which don't" is straightforward. It takes discipline to set up, and habit to maintain. But once you have that visibility, your pricing, your resource allocation, and your business decisions get sharper.

Start this month. Pick your biggest three active projects, create them in your accounting software, and assign last month's costs and revenue to them. You'll probably learn something uncomfortable—and valuable.