Estimate cutting, drilling, fitting, welding, grinding, painting and finishing labor hours for a fabrication job.
Enter the quantity of work and the expected productivity for each operation. Setup time is added separately.
| Operation | Work Quantity | Unit | Productivity | Setup Hours | Estimated Hours |
|---|
| Operation | Typical Planning Basis | Example Productivity |
|---|---|---|
| Cutting | Linear metres of material | 10 m/hour |
| Drilling | Holes | 20 holes/hour |
| Fitting | Assembly pieces | 4 pieces/hour |
| Welding | Weld length | 3 m/hour |
| Grinding | Weld length | 5 m/hour |
| Painting | Surface area | 15 m²/hour |
| Finishing | Parts | 6 parts/hour |
| Inspection | Parts | 10 parts/hour |
| Material Handling | Tonnes | 2 t/hour |
The basic labor estimate is calculated by dividing the amount of work by the expected productivity rate and adding the entered setup time.
The result is then adjusted for the shop efficiency entered in the project settings.
Finally, the contingency allowance is applied.
Cutting hours depend on the cutting process, material thickness, profile complexity, number of cuts, handling and machine setup. Linear cutting length alone may not capture all production time.
For estimating, enter the total effective cutting length and use a productivity rate based on your actual machine and material.
Drilling labor depends on hole count, diameter, thickness, material, access, tooling changes, marking and positioning.
For repetitive work, holes per hour can provide a useful planning basis. For complicated assemblies, setup time should be increased.
Fitting includes positioning, alignment, clamping, tack welding, measurement, adjustment and handling before final welding.
Complex structures can require considerably more fitting time than simple frames, even when their steel weight is similar.
Welding hours depend on weld length, weld size, welding process, deposition rate, position, access, preheat, interpass requirements and the amount of cleaning between passes.
For estimating purposes, weld length divided by a realistic shop productivity rate is a useful starting point, but production history is preferable.
Grinding can include weld dressing, edge preparation, removal of spatter and surface smoothing. Painting and finishing depend on surface area, coating system, preparation requirements and number of coats.
These operations should be estimated separately rather than hidden inside the welding allowance.
What operations can be estimated?
The calculator supports cutting, drilling, fitting, welding, grinding, painting, finishing, inspection, material handling and custom operations.
Can I change productivity rates?
Yes. Every operation has an editable productivity rate.
Does setup time count?
Yes. Setup hours are added to the calculated production time for each operation.
What does shop efficiency mean?
It represents the practical proportion of theoretical productive time achieved after normal interruptions, handling, delays and other shop inefficiencies.
Why is contingency included?
A contingency allows for uncertainty such as minor rework, unexpected fitting adjustments and production variation.
Does crew size reduce labor hours?
The calculator reports labor hours rather than elapsed project duration. Multiple workers can reduce elapsed time while the total labor-hours remain different.
Are the default productivity rates universal?
No. They are planning examples only. Actual rates depend on equipment, material, job complexity and shop practices.
Can this be used for quoting fabrication jobs?
Yes, as an estimating aid. For a quotation, validate the assumptions against historical production data and include all applicable indirect costs separately.