About this tool

PlasticsCalc provides free browser-based injection molding calculators and practical reference guides for engineers, technicians, manufacturers, students, and product teams.

The site includes 33 calculators covering clamp tonnage, shot size, cooling and cycle time, runner and sprue calculations, resin usage, scrap and regrind, production capacity, machine costing, OEE, and tooling economics.

Each calculator includes clear formulas, units, assumptions, worked examples, result interpretation, and limitations. Results are intended for first-pass planning and should be verified against material datasheets, machine specifications, mold conditions, and actual production trials.