CustomPartNet
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August 4, 2026
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Updated August 4, 2026
If you're planning an injection molded part, one of the first questions you'll have is what it's going to cost. This depends on a mix of factors, including part geometry, material choice, wall thickness, and production volume, which can feel daunting at first. However, having a ballpark number early in the process can help you make smarter design choices before you commit a drawing to a supplier.
CustomPartNet's Feature-Based Injection Molding Cost Estimator lets you upload a CAD file (or enter values manually) and get a cost estimate based on the actual features of your part, no hand calculations required. It's a fast way to understand your cost drivers before you request supplier quotes.
Injection molding starts with small plastic pellets that are fed into a heated barrel through a hopper. Inside the barrel, a rotating screw pushes the pellets forward while melting and mixing them into a uniform liquid.
Once enough molten plastic has built up at the front of the barrel, the screw switches roles and acts like a plunger, forcing the melt through a nozzle and into a mold cavity at high pressure. The mold holds that pressure while the plastic cools and takes shape.
When the part has solidified enough to hold its form, the mold opens, an ejector system pushes the part free, and the mold closes again to start the next cycle. Because this cycle repeats with very little variation, injection molding is one of the most efficient ways to produce large volumes of identical plastic parts.
A lot of buyers assume injection molding cost is just "price per pound" of plastic, but that's only part of the story. A realistic estimate accounts for several categories of cost:
Material cost — driven by part volume, material type, and any regrind or scrap allowance
Cycle time — how long each shot takes to fill, cool, and eject, which depends on wall thickness and part geometry
Machine and labor rate — the cost to run the molding press for that cycle time
Tooling cost — the one-time investment in the mold itself, which is separate from the per-part price and amortized over your production run
Number of cavities — multi-cavity molds produce more parts per cycle, which lowers the per-part cost but raises the upfront tooling investment
Secondary operations — any painting, assembly, or finishing steps outside the molding process itself
CustomPartNet's feature-based estimator works by analyzing the geometry of your uploaded CAD file, things like part volume, wall thickness, and projected area, and using that data to model cycle time and material usage. Rather than asking you to plug in formulas yourself, it translates your part's actual features into a cost estimate you can use right away. If you're only interested in cost of making a mold, you can also use the Injection Molding Tooling Cost Estimator for a more granular tooling cost estimator.
Running your part through a cost estimator early has a few advantages:
You can compare design alternatives (wall thickness, rib placement, cavity count) before committing to a mold
You'll have a realistic budget number to bring into supplier conversations
You can catch costly geometry, like unnecessarily thick walls or deep ribs, before it becomes an expensive tooling problem
You'll better understand supplier quotes when they come in, since you already know what's driving the number
A feature-based estimate gives you a realistic ballpark based on your part's actual geometry and material. It's a great planning tool, but final pricing will always depend on your specific supplier, their equipment, and current material and labor rates.
The estimator accepts common CAD formats, including STEP, STP, STL, and 3MF files.
The feature-based estimator focuses on per-part production cost. For mold costs, use the Injection Molding Tooling Cost Estimator alongside it to get a full picture of your investment.
Wall thickness is usually the biggest lever, since it directly affects material usage and cooling time. Cavity count, part size, and secondary finishing also play a significant role.
Yes. Material cost per pound varies widely, and different materials also mold at different cycle times, so switching materials can shift your estimate in more than one way.
Higher volumes let you spread tooling cost over more parts, which lowers your effective per-part price. They may also justify a multi-cavity mold, which further reduces piece price at the cost of a larger upfront tooling investment.
Yes. Having your own cost estimate gives you a reference point when comparing supplier quotes and helps you ask informed questions about where their number comes from.
Try the Feature-Based Injection Molding Cost Estimator → to get a fast, geometry-based cost estimate for your part. When you're ready to move forward, browse our supplier network to compare injection molders, review their sample parts, and request quotes → directly from suppliers matched to your project.