The verdict in three sentences
A consultancy of 70 consultants billing around 1,100 GBP per day that tracks time in spreadsheets and invoices by hand leaks margin without noticing: projects over budget, consultants on the bench, milestone invoices raised late. A professional services automation (PSA) tool costs, as a 2026 order of magnitude in the UK, 70,000 to 130,000 GBP as a custom build, against 25 to 45 GBP per user per month for a market PSA. With weekly timesheets, 12-week forward staffing and automatic progress billing, moving utilisation from 68% to 76% within 6 months is a credible goal.
Where a consultancy loses margin
In a typical London firm, strategy, operations or finance transformation for mid-market and FTSE 250 clients, the finance director receives timesheets at month end, consolidates them in Excel and computes project margin quarterly. When a 120-day fixed-fee engagement burns 150 days, leadership finds out after delivery.
Staffing suffers from the same lag. Partners book people over Slack or email, two projects fight over the same senior manager while an analyst sits on the bench for two weeks. At 1,100 GBP a day, every unbilled day hits the P&L directly.
| Indicator | Spreadsheet management | With a fitted PSA (2026 order of magnitude) |
|---|---|---|
| Visibility on project margin | Quarterly | Weekly |
| Consultant utilisation | 65 to 70% | 74 to 80% |
| Delay to raise a milestone invoice | 10 to 20 days after the milestone | 1 to 2 days |
| Timesheet completion at day 7 | 60 to 75% | Over 95% |
| Overruns caught mid-project | Rarely | Alert at 80% of budget consumed |
| Finance month-end close | 4 to 6 days | 1 to 2 days |
Market PSA or custom build: the costed comparison
Market PSA tools handle timesheets, expenses and simple invoicing. They struggle with the hybrid models common in consulting: fixed fee with milestones, capped time and materials, success fees, expense rebilling with markup, and associate subcontracting.
| Criterion | Custom build | Market PSA |
|---|---|---|
| Upfront investment | 70,000 to 130,000 GBP | Configuration, often 5,000 to 15,000 GBP |
| Recurring cost for 80 users | Maintenance and hosting, quoted separately | 25 to 45 GBP per user per month, 24,000 to 43,200 GBP per year |
| 5-year cumulative cost | 70,000 to 130,000 GBP plus maintenance | About 125,000 to 230,000 GBP |
| Hybrid billing models | Modelled exactly | Partially, through workarounds |
| Forward staffing by skill | Based on your competency framework | Generic |
| Accounting and CRM integration | Your existing tools (Xero, Sage, HubSpot, Salesforce) | Standard connectors |
| Data and code ownership | Yes | Licence |
| Timeline | 6 months | 2 to 4 months |
Below 30 users, a market PSA is almost always the right choice. Above 60 consultants on hybrid contracts, custom becomes competitive from year three.
The modules that add 8 points of utilisation
The custom web application ships in three releases over 6 months:
- Time and expenses: weekly timesheet in 3 minutes on mobile, automatic Friday reminders, approval by the engagement manager.
- Forward staffing: 12-week plan per consultant and skill, bench visibility, tracked staffing requests.
- Project financials: budget in days and pounds, estimate to complete, forecast margin, alert at 80% consumption.
- Progress billing: invoices generated from approved milestones or time, sent to the client and pushed to accounting with VAT handled.
Typical plan: scoping and data model in month 1, timesheets in months 2 and 3, staffing in month 4, financials and billing in month 5, history migration and training in month 6.
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Emma, CFO of a London consultancy, runs 70 consultants over 220 working days a year. At 68% utilisation the firm bills 10,472 days. At 76% it would bill 11,704, or 1,232 more days.
Counting conservatively only half that gain, 616 days at 1,100 GBP, additional revenue reaches 677,600 GBP per year. She adds milestone invoicing brought forward by 15 days on average, which improves cash. With a 110,000 GBP custom project, the investment is covered in about two months of utilisation gain.
FAQ
How much does PSA software for a consultancy cost in 2026?
As a 2026 order of magnitude in the UK, a custom build for 70 consultants costs 70,000 to 130,000 GBP. A market PSA costs 25 to 45 GBP per user per month plus configuration.
How do we get reliable timesheets?
A weekly timesheet prefilled with staffed projects cuts entry to 3 minutes. With automatic reminders, completion at day 7 usually exceeds 95%.
Can one engagement mix fixed fee and time and materials?
Yes, an engagement can combine milestone fixed fees and capped T&M, each with its own billing rules. Margin is calculated across the whole, to the day.
Can it connect to our accounting and CRM?
Yes, invoices export to Xero or Sage, and won opportunities in HubSpot or Salesforce create the engagement. These integrations represent 10 to 15% of the budget.
What utilisation gain is realistic?
Firms moving from chat-based staffing to a shared plan typically gain 4 to 8 points over two quarters. The 68% to 76% target assumes a weekly staffing review.
Let's scope your project. We map your timesheets, staffing and billing rules with a three-release rollout over 6 months. Detailed quote within 48 h. WhatsApp +221 77 596 93 33.
Mohamed Bah
Fondateur, Kolonell
Passionate about digital and entrepreneurship in Africa, Mohamed has been helping Sénégalese businesses with their digital transformation since 2020. Founder of Kolonell, he believes every SME deserves a professional and accessible online présence.
