Manufacturing calculator category

Injection Molding & Plastics Processing calculators

Size the press, set the cycle, check the shot and cost the part. Each calculator uses the numbers a molder already has and says whether the plan works.

What this hub covers

  • Injection molding calculators for press sizing, cycle time, shot and barrel checks, resin drying and cost per part.
  • Browse injection molding & plastics processing calculators for manufacturing planning, quoting, quality, capacity, and operations decisions.

Best calculators in this category

  • Injection Molding Cycle Time: Cycle time from fill, pack and hold, cooling and mold movement times, checked against your quoted cycle.
  • Clamp Tonnage: Clamp force a mold needs, and whether your press can hold it shut.
  • Shot Size: Screw travel a mold's shot needs, and whether it sits inside 20 to 80% of the barrel.
  • Cushion Percentage: Cushion as a share of shot size, checked against your window, with the shift that brings it back.
  • Plastic Part Weight: Predicted weight of one molded part, and whether a weighed part points to a short shot, sink or flash.
  • Runner Weight: Cold runner and sprue weight per shot from the runner layout, and its share of every shot.
  • Mold Cavitation: The fewest cavities a mold needs to meet annual demand after uptime and scrap, and whether your planned count covers it.
  • Mold Parts per Hour: Good parts per hour a mold makes after uptime and scrap, and whether that covers the rate you need.
  • Resin Cost per Part: Resin cost of each good molded part, counting runner, rejects and the regrind your print allows.
  • Regrind Percentage: Regrind share your press makes when runners and rejects go back in, checked against your print or datasheet limit.
  • Plastic Regrind Savings: Net yearly savings from grinding scrap back into production, and whether the granulator meets your payback hurdle.
  • Scrap Resin Cost: Yearly cost of resin you cannot regrind, net of scrap sales, and what hitting your scrap target is worth.

Common manufacturing problems solved

  • injection molding
  • plastic processing
  • clamp tonnage
  • shot size
  • resin cost
  • mold cavitation

Live market signals for this industry

  • The producer price index for plastic resins and materials stands at 280.569 (BLS, Aug 2026), up 6.6% from a year earlier. Quotes priced off last quarter's material cost miss this move.
  • The U.S. has 9,635 plastics product manufacturing establishments employing about 677,302 workers (Census County Business Patterns, 2023).

Category questions

  • Where do the default values come from? They are illustrative numbers for a typical job so the page shows a worked answer. Replace them with your CAD data, press nameplates, resin datasheets and quotes before you rely on a result.
  • Why do some results show a warning? A warning means the plan fails a limit you entered or one from a cited source, such as a press rating or a resin's maximum residence time. The message states the gap and what to change.
  • Can I download the calculation? Yes. Every calculator has an Excel workbook with live formulas that match the page, so you can check the math or reuse it in a quote.
  • Why is a result blank? An input is missing or outside its valid range, so there is no honest number to show. The message above the result names the input to fix.

Last reviewed 2026-07-02.