28 April 2026
The real cost of recruiting the right person
A £100,000 salary is not a £100,000 decision. In a realistic UK model it equates to roughly £133,000 to £143,000 in first-year cash cost, and around £147,000 to £157,000 in first-year economic cost once lost productivity is counted.
In the UK built environment, an employee is rarely just a salary cost. They are a bundle of direct expense, time demand and operational risk. That matters because firms are still hiring into a market shaped by skills pressure, rising employment costs and tighter commercial scrutiny.
The common mistake
Most businesses model employee cost as salary plus employer's National Insurance. That misses pension, recruitment fees, IT and software setup, director and HR time, onboarding, ramp-up loss, absence, early mistakes, and the possibility of having to run the whole process again if the hire fails.
The context has tightened too. From April 2025 the employer NI threshold fell to £5,000 and the rate rose to 15 per cent. The Institute for Fiscal Studies estimated that change alone adds roughly £900 per employee on median earnings. The Office for National Statistics puts median full-time earnings at £39,039.
And recruitment fees are usually a percentage of salary, not a flat cost. UK recruiter-market guidance commonly places permanent-hire fees around 15 to 20 per cent of salary, with some published terms higher again. A 10 to 20 per cent modelling range is commercially reasonable, and 10 per cent is the low end, not the norm.
A better measure: true employment cost
The useful commercial definition is salary, plus employer NI, plus employer pension, plus recruitment fee, plus IT and software setup, plus internal hiring and onboarding time, plus absence cost, plus ramp-up productivity shortfall, plus failure and reset risk.
Run the numbers on the median salary of £39,039 and the first-year economic cost lands at roughly £60,900 to £64,800 depending on the recruiter fee. Run them on a £100,000 hire and the employment package is already about £115,600 before recruitment or onboarding is counted; the first-year economic cost reaches roughly £147,000 to £157,000.
The reset cost when a hire goes wrong
If the employee leaves early or proves to be the wrong hire, the business does not only lose salary. It loses the recruiter fee, leadership and HR time, onboarding and mentoring, software and equipment setup, output during the vacancy, and process knowledge. Then it pays for a second recruitment cycle.
For a £100,000 hire, the agency line alone may be £10,000 to £20,000 before management time and lost momentum are counted. This is the strongest reason to treat employment as a risk-adjusted operating cost rather than a payroll number.
Why this matters for AI and automation
The strongest case for AI agents and automation is not that they replace people. It is that they reduce the risk-adjusted cost of employment by removing repetitive admin, improving consistency, surfacing issues earlier and lowering dependency on expensive human time for low-value tasks.
In practice that means less director time chasing information, less HR and management time lost to administration, fewer missed steps, better documentation, lower rework risk, and senior staff spending their hours on judgement, negotiation and client-facing work.
Put the two numbers side by side. A capable automation layer typically costs a fraction of one mid-level hire's true first-year cost, carries no NI, no pension, no notice period and no reset risk, and its capacity does not walk out of the door. For most construction firms this is not mainly a technology story. It is a margin, risk and throughput story.
A salary is only the visible part of the employment cost. Before your next hire, it is worth asking whether the role is genuinely new capability, or whether it is admin that should never have needed a person at all.