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Shot Weight Calculator

Shot weight from part volume, material density, cavity count and runner allowance — including the density correction for glass fiber and mineral fillers. Free and no sign-up required; you can switch to the other 14 tools from the tabs above.

Machine Selection
Process
Auxiliaries & Cost
Part weight18.1 g
Density used0.905 g/cm³
Total shot weight79.6 g

The weight is calculated with the solid density (the value you would read on a scale). The melt volume in front of the screw needs the melt density — the transfer button applies that conversion for you.

These calculations produce guide values; the final selection has to be based on the part geometry, the mold design and the data from the material manufacturer. For an assessment specific to your application, contact our technical support team.

How is this calculated?

The shot weight is the total material the machine injects in each cycle: part weight x number of cavities plus the runner. The part weight comes from the CAD volume multiplied by the density of the material; because fillers such as glass fiber raise the density noticeably, the compound density is corrected with the rule of mixtures.

Shot [g] = Volume [cm³] x Density [g/cm³] x Cavities x (1 + Runner %)

The weight here is calculated with the solid density (the value you would read on a scale). The volume in front of the screw, on the other hand, needs the melt density — the transfer button carries the shot to the Screw Capacity tab with that conversion applied.

The method, the formula and the limits of each tool are explained directly underneath it, and the explanation changes with the tab you select. The results are engineering guide values; for an assessment specific to your application when choosing the final machine and equipment, contact our technical team.

Prepared by:Uğur Çamlıca· Teknik Part · Sources: manufacturer documentation and field practice