Lift Sizing Calculator - Part M Passenger Lift Car & Shaft Dimensions
Calculate passenger lift car dimensions and shaft size for wheelchair access per Part M.
Total number of floors the lift will serve
Average number of people per floor during peak use
Part M: minimum 1100mm × 1400mm car, 900mm door
How We Calculate This
This calculator determines passenger lift car dimensions, shaft size, and capacity based on UK Building Regulations Approved Document M, BS EN 81-70:2021, and BS 8300:2018.
Car sizing
The minimum car size is determined by accessibility requirements and expected usage. Part M requires 1100mm × 1400mm for wheelchair access with a 900mm clear door opening. Larger cars (1100mm × 2100mm) are needed for stretcher provision or firefighter lifts.
Shaft dimensions
Shaft dimensions are calculated from the car size plus clearances for machinery:
- Width: Car width + 250mm clearance each side
- Depth: Car depth + 200mm (door) + 350mm (counterweight)
- Pit depth: 1200-1600mm depending on lift speed
- Headroom: 3600-4200mm above top floor landing
Load rating
Lift load ratings follow BS EN 81-20. A standard 8-person wheelchair-accessible lift has a 630kg rating. A 13-person stretcher or firefighter lift is rated at 1000kg. The rated load determines motor size, counterweight, and structural support requirements.
Frequently Asked Questions
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Last updated: March 2026
All calculations are estimates. Verify with your supplier.