Salary is only the first line item
Employer cost starts with salary but quickly expands into NI, pension, onboarding, equipment, software and line-manager time. Most budgeting errors happen when salary is treated as the total cost baseline.
In 2026/27, employer NI is 15% above the £5,000 threshold. Auto-enrolment pension adds at least 3% of qualifying earnings. Combined, these statutory items can add a sizeable uplift before any operational overheads.
A robust model shows annual and monthly totals and reports cost above salary as a percentage. That percentage is useful for hiring managers who need a quick way to compare role options and timing.
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A repeatable cost model
Start with gross salary, then calculate employer NI on current-year rates and thresholds. Next add minimum employer pension on qualifying earnings. Finally include overhead assumptions that are specific to your organisation.
Overheads normally include laptop and peripherals, SaaS licences, security tooling, desk space, and training. For many office-based teams, £2,000 to £5,000 per employee per year is a common planning range.
Use one model template across finance and people teams so approval conversations are consistent. This reduces disputes created by conflicting spreadsheets.
Using the model for decisions
Use monthly-first outputs for cash planning and annual outputs for headcount plans. Managers usually understand monthly burn faster, while finance needs annual totals for forecasting.
When comparing candidates or grades, evaluate the full cost delta, not salary delta. The NI and pension increments can materially change affordability near budget limits.
Treat the calculator as a decision aid, not legal advice. Employment law and contractual terms can introduce additional obligations beyond baseline statutory cost estimates.
Stop doing this by hand — Sage Payroll works out employer NI, pension auto-enrolment, statutory sick and maternity pay and files RTI to HMRC automatically for UK employers. Try Sage Payroll →
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