Why this needs two numbers

The global sum is £130.07 per weighted patient from 1 April 2026, applied to your Contractor Weighted Population under the Carr-Hill formula. The London Adjustment is £2.18 per registered patient with a Greater London Authority postcode, and it is a separate addition rather than something already inside the £130.07.

Practices that model on raw list size and assume London is baked in get both ends of that wrong, usually in the same spreadsheet. If you do not know your weighted population, that is the first thing to find out — it is the number your largest income line is actually paid on.

The out-of-hours deduction

Where the practice has opted out of out-of-hours, the deduction is 4.70% of the Initial Global Sum Monthly Payment, which works out at £6.11 per weighted patient. It is applied whether or not anyone in the practice thinks about it.

What actually moves your weighted population

Its statutory name is the Global Sum Allocation Formula — the SFE never uses the words “Carr-Hill” — and Annex B sets out six components. Knowing which ones your practice is exposed to tells you whether a change in your list will move your income more or less than proportionately.

  • Age and sex workload. Indexed to a male aged 5–14 at 1. A male aged 85 or over scores 6.27 and a female 6.72; a male aged 0–4 scores 3.97. An ageing list is worth substantially more than a flat one.
  • Additional needs. Two variables — standardised limited long-standing illness, and the standardised mortality ratio for under-65s.
  • List turnover. First-year registrants generate 40–50% more workload, and an uplift factor of 1.46 applies to every new registrant in their first year. A practice in a high-churn area is paid for it.
  • Care homes. A factor of 1.43 per patient in a CQC registered nursing or residential home.
  • Staff market forces. Weighted at 48% — the average proportion of global sum accounted for by staff expenses.
  • Rurality. Population density and dispersion, weighted at 58% and applied only to the expenses element. For a multi-site practice, dispersion is measured from the principal surgery — which is worth checking if you have branched since the measurement was taken.

The London adjustment sits outside all of that: Annex B calls it expressly an “off-formula” adjustment, which is why this tool asks for it separately.

A review is live, and nothing has changed yet

DHSC announced a six-month NIHR-led review of the formula on 9 October 2025, citing evidence that practices in poorer areas receive nearly 10% less per patient and that parts of the formula rely on data around twenty-five years old. There is no implementation date and no change for 2026/27. Budget on the formula as it stands; do not budget on the review.