The real cost of hiring a senior developer in the UK in 2026

Short answer

A senior developer outside London on the median £65,000 salary costs about £88,000 in the first year once 15% employer National Insurance, pension and a recruiter fee are added, before equipment and benefits. In London it’s more. Hiring takes months, and from 1 January 2027 a hire that doesn’t work out costs more to undo.

The headline salary

The median advertised salary for a senior software developer outside London is £65,000 (IT Jobs Watch). London medians run from about £80,000 for senior developers to £95,000 for senior software engineers. Specialists in AI, cloud and security cost more again.

What gets added on top

Cost	How it’s worked out	On £65,000
Employer National Insurance	15% of earnings above £5,000 (since April 2025)	£9,000
Pension	At least 3% of qualifying earnings (£6,240 to £50,270)	£1,321
Recruiter fee	Typically 15 to 25% of first-year salary, often around 20%	About £13,000
First-year total	Before equipment, software and benefits	About £88,000

A small employer with unused Employment Allowance (up to £10,500 a year) pays less NI. Use the calculator to try your own figures.

The costs that don’t show on a payslip

Time to hire. Guides estimate anywhere from four to twelve weeks from advert to accepted offer. Senior candidates then work a notice period, often one to three months.
Ramp-up. Even a great hire takes weeks to understand your product, your users and your quirks.
Your time. Writing the role, screening, interviewing and onboarding usually lands on the busiest technical person you have.
Single-person dependency. One person’s skills, one person’s holidays, one person who might leave.

Why a bad hire costs more from January 2027

Under the Employment Rights Act 2025, from 1 January 2027 the qualifying period for unfair dismissal falls from two years to six months, and the cap on compensation is removed entirely. Employees with six months’ service on that date are protected straight away (BCLP). A mis-hire made in January is much harder to put right by July. That’s a fact about hiring, not legal advice: speak to an employment lawyer about your own situation.

What are the alternatives?

Contractors. Senior UK contractors typically charge around £550 to £850 a day (Mecanik). Flexible, but expensive for ongoing work and you still manage them.

Agencies. Established UK agencies typically charge £75 to £150 an hour, usually through fixed quotes and change requests. How that compares.

A fractional product team. A flat monthly fee for continuous output from a team, with no employment risk. Ours costs £30,000 a year for one track (Embedded) or £48,000 for two tracks plus monthly CTO and planning time (Embedded Plus) at current pricing. How it works.

So should you hire?

If you need a large permanent team and software is your core product, yes. If you need more capacity now, aren’t sure the role will last, or want senior judgment without a senior salary, a fractional team is lower risk and quicker to start. Plenty of teams use one while they recruit.

Questions

How much is employer National Insurance on a developer’s salary?

15% of earnings above the £5,000 secondary threshold, since April 2025. On a £65,000 salary that’s £9,000 a year, less if you have unused Employment Allowance.

How much do UK recruiters charge for a developer placement?

Typically 15 to 25% of the first-year salary, often around 20%. On a £65,000 senior hire that’s about £13,000.

What changes for unfair dismissal in January 2027?

From 1 January 2027 the qualifying period falls from two years to six months and the compensation cap is removed. Take employment law advice for your own situation.

The real cost of hiring a developer in 2026.