Lift Sizing Calculator

Work out lift sizing instantly with clear inputs, formula shown and shareable results.

About Lift Sizing Calculator

Lift provision is judged on five minute handling capacity: the share of the building population a group of lifts can move in a peak five minute window, typically 11-15 percent for an office. Each lift moves 80 percent of its rated capacity per round trip, and round trip time grows with the number of floors and the passenger transfer time at each stop.

Formulas

Round trip time

RTT = door and start time + 2 x floors x flight time + loaded passengers x transfer time

Handling capacity

Per lift = 300 / RTT x loaded passengers; lifts = ceil(population x target / per lift)

Worked example

With the default values below, Lift Sizing Calculator returns Lifts required of 3. Change any input above and every figure here is recalculated in your browser.

Inputs used

Building populationminimum 1 people: 400 people
Floors served above groundminimum 1: 10
Target five minute handling capacityaccepts 1–30 %: 12 %
Car capacityminimum 2 people: 13 people

Results

Lifts required: 3
Passengers to move in five minutes: 48.0 people
Estimated round trip time: 132.4 s
Handling capacity per lift: 23.56 people/5 min

Step by step

1Values used
2Round trip time
3Handling capacity
4Lifts required= 3
5Passengers to move in five minutes= 48.0 people
6Estimated round trip time= 132.4 s
7Handling capacity per lift= 23.56 people/5 min

Assumptions and limits

The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
Figures are rounded for display to 2 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
Preliminary estimate only. Lift traffic analysis should be carried out with proper simulation by a vertical transportation specialist.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Preliminary estimate only. Lift traffic analysis should be carried out with proper simulation by a vertical transportation specialist.

Frequently Asked Questions

How is the Lift Sizing figure worked out?

RTT = door and start time + 2 x floors x flight time + loaded passengers x transfer time. Lift provision is judged on five minute handling capacity: the share of the building population a group of lifts can move in a peak five minute window, typically 11-15 percent for an office.

Why only 80 percent of rated capacity?

Passengers stop boarding well before the car is physically full. Traffic studies consistently show 80 percent as the practical loading in normal use.

What values do I need to enter?

This calculator takes 4 inputs: Building population, Floors served above ground, Target five minute handling capacity, Car capacity. The pre-filled defaults are a realistic worked example — replace them with your own site or project figures.