Dumbwaiter Sizing Calculator
Dumbwaiter dimensions and capacity from intended loads.
About this calculator
Motor Power (HP) depends on exactly one input: Load Capacity (kg). This isn't approximate -- it's algebraic. The engine estimates car weight from car area (carWeightKg = carAreaSqM × 80 + 30), adds it to Load Capacity for Total Lift (totalLiftKg = loadCapacityKg + carWeightKg), and separately adds it to 40% of Load Capacity for the Counterweight (counterweightKg = carWeightKg + loadCapacityKg × 0.4). The net lift force is their difference: (totalLiftKg − counterweightKg) × g.
Substitute the two expressions and carWeightKg cancels completely, leaving netLiftForceN = 0.6 × loadCapacityKg × g -- car dimensions never actually appear in the result. Car Width, Car Depth, and Car Height are all completely inert on Motor Power (HP) and every other lift-force-derived output; changing them by any amount across their full range moves Motor Power by less than 0.005 HP, well within rounding noise. That doesn't make Car Width and Car Depth useless inputs -- they correctly and directly drive Car Area (m²), Car Volume (liters), the Area Code Compliant flag, and Shaft Width/Depth (car dimension + 150 mm clearance). It's specifically the motor sizing calculation, and only the motor sizing calculation, where the counterweight formula's built-in 40%-of-load estimate happens to offset the car-weight term exactly.
Inputs
Results
Area code compliant (1=yes)
1
Figures current as of 2004. Source: ASME A17.1, Safety Code for Elevators and Escalators, Section 7 (Dumbwaiters)
How to Use This Calculator
- Enter Load capacity (kg), Car width (mm), and Car depth (mm).
- Set Car height (mm), Number of stops, and Floor-to-floor height (mm).
- Review the Area code compliant (1=yes) result.
- Use Car area (m²) and Car volume (liters) to inform your decision.
What each input means
- Load capacity (kg)
- Maximum load weight. ASME A17.1 limit: 227 kg (500 lbs).
- Car width (mm)
- Interior width of the dumbwaiter car (max ~900 mm).
- Car depth (mm)
- Interior depth of the dumbwaiter car.
- Car height (mm)
- Interior height. ASME A17.1 maximum: 1219 mm (48 in).
- Number of stops
- Number of landings served by the dumbwaiter.
- Floor-to-floor height (mm)
- Typical floor-to-floor height in the building.
What each result means
- Area code compliant (1=yes)
- 1 if car area is within the 0.836 m² (9 sq ft) ASME limit.
- Car area (m²)
- Platform area of the dumbwaiter car.
- Car volume (liters)
- Interior volume of the dumbwaiter car.
- Total travel (m)
- Vertical distance between lowest and highest stops.
- Travel time (seconds)
- Time for one full trip (bottom to top).
- Motor power (HP)
- Required motor horsepower.
- Shaft width (mm)
- Minimum shaft/enclosure internal width.
- Shaft depth (mm)
- Minimum shaft/enclosure internal depth.
- Trips per hour
- Estimated round-trip throughput.
- Capacity (kg/hour)
- Maximum material throughput at full load.
How this is calculated
Worked example, using the default values
- Identify Input Parameters4 parametersLoad capacity (kg) = 100, Car width (mm) = 610, Car depth (mm) = 610, Car height (mm) = 914 = 6 input(s) provided
- Calculate Area code compliant1 = 1
- Calculate Car areaCar area = (carWidthMm / 1000) * (carDepthMm / 1000)0.3721 = 0.3721
- Calculate Car volumeCar volume = carAreaSqM * (carHeightMm / 1000) * 1000340.1 = 340.1
Figures and sources
- ASME A17.1 Section 7 dumbwaiter limits: 227 kg (500 lb) max capacity, 0.836 m² (9 sq ft) max car area, 1219 mm (4 ft) max interior car height (2004) — ASME A17.1, Safety Code for Elevators and Escalators, Section 7 (Dumbwaiters)
Engine last updated . Checked against 2 independently-derived tests — how we verify calculators. Built by Paul Gunder, a software engineer, not a licensed financial, medical, or legal professional.
Frequently Asked Questions
If I make the car bigger, does Motor Power (HP) go up?
No -- Motor Power (HP) is driven entirely by Load Capacity (kg) and doesn't respond to Car Width, Car Depth, or Car Height at all, even at the extremes of their ranges. The counterweight in this calculator is sized as car weight plus 40% of load capacity, and that car-weight term cancels exactly against the car weight added to the total lift, leaving the net lift force as a function of load capacity alone.
Then what do Car Width and Car Depth actually change?
They correctly drive Car Area (m²), Car Volume (liters), the Area Code Compliant flag (0.836 m² / 9 sq ft, the maximum car area ASME A17.1 Section 7 allows for a dumbwaiter), and Shaft Width/Shaft Depth (each dimension plus a 150 mm clearance). It's specifically the motor power calculation that ignores them -- every dimensional output responds to car size exactly as expected.
Why does the formula even calculate car weight if it doesn't affect Motor Power?
Car weight is genuinely used in two intermediate sums -- Total Lift and Counterweight -- but because the counterweight is defined as car weight plus 40% of load capacity, and total lift is car weight plus the full load capacity, subtracting one from the other cancels the car-weight term exactly. The two car-weight terms are mathematically identical and cancel by construction, not by coincidence.
Does a longer travel distance (more stops or taller floors) change the motor power recommendation?
No. Number of Stops and Floor-to-Floor Height change Total Travel, Travel Time, Trips Per Hour, and Capacity (kg/hour), but the motor sizing formula in this calculator only accounts for lifting the rated load against gravity, not for travel distance or speed-related power draw, so Motor Power (HP) stays fixed as travel distance changes.
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