Calculator · Excel + PDF

The Locum vs Substantive Calculator.

Like-for-like comparison under UK 2026/27 tax and pension rules.

What this Calculator is for

A locum day rate of £800 is not equivalent to a substantive annual salary that delivers the same gross income on paper. The substantive role attracts NHS pension at 1/54 accrual; the locum work does not. The substantive role has paid leave; the locum work does not. The substantive role is paid through PAYE; the locum work has its own tax treatment.

This Calculator does the comparison properly. The user enters the substantive offer and the locum equivalent. The Calculator computes both under UK 2026/27 tax, pension, and NI rules, and produces a like-for-like comparison of take-home pay, pension value, and total economic value over a chosen time horizon.

What's inside

6 sheets in a single Excel file, plus an accompanying PDF user guide.

Substantive — inputs for the employed role
Locum — inputs for the sessional/locum equivalent
Assumptions — UK 2026/27 tax, NI, and pension parameters
Comparison — side-by-side numerical comparison
Time-horizon view — total economic value across 1, 5, and 10 years
Methodology — what the Calculator does and does not include

How it reads

"The substantive role and the locum role are not the same kind of thing, even when the headline gross figures look similar. One is a contractual relationship that comes with pension accrual, statutory entitlements, and career-progression structure; the other is a market transaction in which the clinician sells sessions at a market rate and absorbs the cost of everything else."

— from the PDF user guide, Reading the comparison

Who it's for

Trainees approaching CCST. Substantive consultant post versus locum consultant work is the first major commercial decision of consultant life.
Salaried GPs considering a locum switch. A common decision; rarely made with proper analysis.
Consultants weighing additional NHS sessions against private locum work. The marginal session has very different economic value depending on how it's structured.

What's not in this Calculator

It is a tool, not regulated advice. It does not provide personalised financial, legal, or tax recommendations. Those require a qualified professional who knows your full circumstances. The calculator's purpose is to make those conversations substantive rather than passive.

It focuses on UK clinical practice specifically — the regulatory and commercial environment of the UK.

What's related

The Limited Company Decision Calculator — if the locum-side analysis points toward private work, the structural decision that follows. £59.
The Consultant Contract Evaluator — if the comparison is between two substantive consultant offers, decomposes them in more detail. £59.