Engineering tools

Injection moulding part cost calculator

The cost of an injection moulded part is mostly three numbers: material (part weight × resin price, plus the runner’s share), machine time (cycle time ÷ cavities × the machine-hour rate), and tooling amortisation if you spread the mould cost over its production life. This calculator runs all three from your own figures, with a reject allowance — the same arithmetic every serious quote is built on.

Reading a quote with this tool

Run a supplier’s quoted cycle, cavitation and your resin price through the calculator. If the quoted part price sits far above the arithmetic, the difference is overhead, secondary operations, risk — or margin; ask which. If it sits below, be more careful still: someone plans to recover it later, usually through the tooling, change orders or quality. Honest quotes survive this arithmetic in daylight.

The inputs that move the answer most

Cycle time and cavitation dominate: halving the cycle or doubling the cavities halves the machine cost per part — which is why tooling decisions are economic decisions, and why cycle-honest DFM (thinner uniform walls, sensible gates) pays every single shot. Estimate cycles with the cycle-time calculator, and machine fit with the shot-size and clamping-force tools.