Conveyor Belt Length Calculator
Rolled Belt
Installed (2-Pulley)
Millimeters (mm)
Inches (in)
Centimeters (cm)
Estimated Total Length:
Required Belt Length:
How to Calculate Conveyor Belt Length
Accurate measurement of a conveyor belt is critical for maintenance, replacement ordering, and system tensioning. Depending on whether your belt is currently stored on a roll or installed on a machine, different mathematical formulas apply.
1. Calculating Length of a Rolled Belt
When the belt is wound in a roll, you can calculate the length without unrolling it by using the mean diameter method. You need the outside diameter, the core diameter, and the total number of wraps (rings) of the belt.
Length = (D + d) × n × 0.00157 (if result in meters and inputs in mm)
General: L = π × n × (D + d) / 2
General: L = π × n × (D + d) / 2
- D: Outside diameter of the roll.
- d: Outside diameter of the core.
- n: Number of wraps/turns of the belt.
2. Calculating Length of an Installed Belt (2-Pulley System)
For a standard two-pulley setup, the formula accounts for the straight sections and the arc of contact around each pulley.
L = 2C + 1.57(D + d) + [(D – d)² / 4C]
- C: Distance between the centers of the two pulleys.
- D: Diameter of the larger pulley.
- d: Diameter of the smaller pulley.
Example Calculation
Suppose you have a rolled belt with an outer diameter of 1000mm, a core diameter of 200mm, and 50 wraps. Using the mean diameter formula:
Mean Diameter = (1000 + 200) / 2 = 600mm
Length = π × 600 × 50 = 94,247mm (or 94.25 meters)
Key Considerations for Accuracy
When performing these calculations, keep these factors in mind:
- Belt Stretch: New belts may stretch up to 1-3% during initial use.
- Take-up Position: If the belt is installed, ensure the take-up pulley is in the minimum position to allow for maximum adjustment.
- Measurement Units: Always ensure all inputs (diameters and distances) use the same units (e.g., all inches or all millimeters) before starting the calculation.