Elevator Pit Depth Calculator

Pit depth from car height and buffer requirements.

Rated speed (m/s)

Buffer type

Car inside height (m)

Compensating sheave

Additional margin (mm)

Tab to move between fields

Required pit depth (m)

1.5

Pit depth (mm)1,500

Buffer stroke (mm)150

Pit ladder height (m)2.4

Sump pump needed1

How to Use This Calculator

Enter the Rated Speed (m/s) — this is the primary determinant of pit depth requirements.
Select Buffer Type (oil or spring) per the elevator design.
Input Car Inside Height (m) and toggle Compensating Sheave if present.
Set the Additional Safety Margin (mm) required by your AHJ.
Review Required Pit Depth (m and mm) to specify in architectural drawings.

How the result changes with Additional margin (mm)

Rated speed (m/s): Elevator rated speed. Spring buffers limited to 1.0 m/s.
Buffer type: 0 = Spring buffer (up to 1.0 m/s), 1 = Oil buffer (any speed).
Car inside height (m): Interior height of the elevator car.
Compensating sheave: 0 = No compensating ropes/chains, 1 = Has compensating sheave in pit.
Additional margin (mm): Extra clearance beyond code minimums for construction tolerance.

Required pit depth (m): Total pit depth from finished lobby floor to pit floor.
Pit depth (mm): Pit depth in millimetres.
Buffer stroke (mm): Required buffer compression stroke.
Pit ladder height (m): Recommended pit access ladder length.
Sump pump needed: 1 = recommended (pit > 1.2 m), 0 = not required.

Identify Input Parameters
4 parameters
Rated speed (m/s) = 1.5, Buffer type = 1, Car inside height (m) = 2.4, Compensating sheave = 0 = 5 input(s) provided
Calculate Required pit depth
Required pit depth = ceil(pitDepth * 20) / 20
1.5 = 1.5
Calculate Pit depth
Pit depth = ceil(pitDepth * 20) / 20
1500 = 1500
Calculate Buffer stroke
150 = 150