Site Welfare Calculator
Calculate CDM welfare facilities for construction sites: toilets, washing stations, rest areas, drying rooms, first aid and drinking water based on worker numbers.
Maximum workers on site at any time
Required for all sites under CDM
Required for wet clothing storage
HSE L74: high-risk → 1 first aider per 25; low-risk → 1 per 50
Weekly hire cost per toilet unit
Weekly hire for combined welfare unit
How We Calculate This
This calculator determines the minimum welfare facilities required under CDM 2015 Schedule 2 for construction sites, based on the peak number of workers.
The formula
Toilets = Peak workers ÷ 7 (rounded up)
Washing stations = Peak workers ÷ 7 (rounded up)
Rest area = Peak workers × 1 m²
First aiders = Peak workers ÷ 25 (rounded up, min 1)
For 30 workers: 5 toilets, 5 washing stations, 30m² rest area, 15m² drying room, 1 first aid kit, and 2 first aiders.
CDM welfare requirements
- Toilets and washing facilities: clean, maintained, 1:7 ratio
- Rest area: heated, seating, food preparation
- Drinking water: clearly marked, accessible
- Changing/drying: separate from work areas, heated
Frequently Asked Questions
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Last updated: March 2026
All calculations are estimates. Verify with your supplier.