Injection Molding Tools
Injection Molding Piece-Price Calculator
Enter part geometry, resin cost, machine rates, and tooling — get a fully transparent cost breakdown and selling price instantly. No spreadsheet needed.
Material cost
Processing $/part
Setup allocation
Tooling amortization
Gross margin
Regrind credit
CSV export
Inputs changed — click Calculate to update ↻
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Selling Price Per Part
—
—
Gross Margin
Good Parts / Hr
—
after scrap
Eff. Material
—
g / good part
Loaded Rate
—
$/hr all-in
Shot Mass
—
g / shot
Cost Breakdown
Bars proportional to largest component
Total Unit Cost
100%
—
Step-by-Step
Cycles / hr
3600 / ?s
—
Good parts / hr
cycles x ? x (1-?%)
—
Eff. material
(part+(1-reg)xrun)/(1-scr)
—
Material $/part
eff.mat/1000 x $/kg
—
Processing $/part
loaded rate / gp/hr
—
Setup $/part
setup hr x rate / qty
—
Tooling $/part
tooling / lifetime
—
Selling price
cost / (1 – margin%)
—
Material floor = part wt / 1000 x $/kg
= ? / 1000 x $? = —/part
Quote below this with cold runners? Revisit assumptions.
= ? / 1000 x $? = —/part
Quote below this with cold runners? Revisit assumptions.
Static values · no Excel formulas
How the formula works
Every input maps directly to one term in a transparent, industry-standard costing formula. No black-box markups.
Piece Price = (Material + Processing + Setup + Tooling + Other) / (1 – Gross Margin)
Good parts/hr = (3600 / Cycle time) x Cavities x (1 – Scrap%)
Material g/part = (Part g + (1-Regrind%) x Runner g/cav) / (1-Scrap%)
Processing $/part = Loaded $/hr / Good parts/hr
Setup $/part = Setup hr x Loaded $/hr / Order qty
Tooling $/part = Tooling cost / Mold lifetime qty
Pitfall avoided
Burying runner cost
Runner weight explicitly separated with configurable regrind credit. Zero regrind = full cold-runner cost passed through.
Pitfall avoided
Under-counting setup
Setup allocated per order, not per lifetime. Small orders correctly carry a higher setup burden.
Pitfall avoided
Margin vs. markup
25% margin = Price = Cost / 0.75 = Cost x 1.333. Not Cost x 1.25. Confusing the two causes systematic under-pricing.
Pitfall avoided
Ignoring material floor
Sanity check shows minimum material cost. Any quote below this with cold runners is almost certainly wrong.
One-line what-ifs
Use these benchmarks to quickly sense-check a quote or explain trade-offs to a customer.
Hot runner vs. cold runner
Setting runner weight to 0 eliminates runner material cost. Hot runners also pay off through shorter cycles and no purge waste on color changes.
2-cavity to 4-cavity
Doubling cavitation roughly halves processing $/part, but raises tooling cost. Quote the payback period: typically 6-18 months at moderate volumes.
Cycle time +/-10%
A 10% faster cycle cuts unit cost by ~5-6%. Cycle time is the highest-leverage DFM lever because it drives processing cost without affecting material or tooling.
Scrap 3% to 5%
A 2-point scrap increase raises unit cost by ~1-2%, hitting both material yield and throughput. Compounds at large volumes.
Frequently asked questions
Answers to the most common questions about injection molding cost estimation.
How do you calculate injection molding piece price?
Piece price = (Material + Processing + Setup + Tooling + Other) / (1 – gross margin). Processing cost per part = loaded hourly rate / good parts per hour. Good parts/hr = (3600 / cycle time) x cavities x (1 – scrap rate). Material cost accounts for part weight, runner weight, regrind credit, and yield loss.
What is a typical injection molding cycle time?
Thin-wall packaging parts cycle in 5-15 seconds; thick structural parts run 20-60+ seconds. Rule of thumb: 2-3 seconds per mm of wall thickness for semi-crystalline resins. Cycle time is the single largest driver of processing cost per part.
How does cavitation affect injection molding piece price?
More cavities reduce processing cost per part proportionally but raise tooling amortization. Moving from 2 to 4 cavities at 50,000 parts/year typically pays back in 9-18 months; at 200,000+ parts/year, 4-cavity is almost always economically superior.
What is regrind utilization in injection molding?
Regrind is runner and sprue waste ground into pellets and blended back into virgin resin. Set to 0% for medical, food-contact, optical, or high-precision applications where regrind is prohibited by specification or regulation.
What is the difference between gross margin and markup?
Gross margin = (Price – Cost) / Price. Markup = (Price – Cost) / Cost. A 25% gross margin equals 33.3% markup. This calculator uses margin: Price = Cost / (1 – 0.25) = Cost x 1.333. Confusing the two causes systematic under-pricing.
What is a loaded hourly rate for injection molding?
Machine depreciation and energy (press rate) + direct labor + allocated overhead (utilities, supervision, facilities). Typical range for a mid-size hydraulic press in North America: $60-$120/hr all-in.
