Accurate pricing is the difference between landing profitable jobs and leaving money on the table in injection molding. Most shop owners either underbid from incomplete cost analysis or overbid and lose contracts to competitors. Getting your quote right requires breaking down material, tooling, machine time, and overhead into specific line items.
The Core Cost Components You Can't Skip
Every injection molding quote hinges on five hard costs. Material cost is straightforward—multiply your per-pound resin price by total part weight plus runner and sprue weight (typically 10–25% added waste). Tooling cost is the biggest variable: a single-cavity aluminum mold for a small part runs $800–$3,500, while multi-cavity steel tooling for high-volume parts costs $5,000–$25,000+. Machine time depends on cycle time (how long each shot takes) multiplied by your hourly rate; most shops charge $40–$150 per machine hour depending on equipment and location. Labor for trimming, assembly, and QC adds 15–30% on top. Finally, overhead—utilities, facility rent, equipment depreciation—should add 20–40% to your direct costs.
Calculate Your Effective Hourly Rate
Don't guess your machine rate. Track actual production data over a month: total billable machine hours, revenue generated, and total operating costs (including payroll, rent, utilities, maintenance). Divide monthly costs by billable hours to get your true cost per hour, then mark it up 40–60% to cover profit margin and contingency. If your shop costs $8,000 per month to run and you bill 100 machine hours, your cost per hour is $80. Mark it up 50% and quote $120 per hour. This forces discipline and prevents the common mistake of undercutting because you "haven't used that machine much anyway."
Break Down Cycle Time Realistically
This is where most bad quotes originate. Cycle time includes material heating, injection phase, cooling time, mold opening, part ejection, and manual handling. Don't rely on manufacturer specs alone—run test shots. A seemingly simple box might cycle in 25 seconds on the datasheet but takes 40 seconds in your shop due to mold complexity or your equipment setup. Factor in downtime: account for 5–10% of total production time for mold adjustments, material changes, and equipment hiccups.
Charge Separately for Mold Modification and Repairs
First-article inspection often reveals draft angle issues, gate location problems, or cooling imbalances. Quote mold fixes as separate line items—not as "included in tooling." Polishing hot spots costs $200–$800 per cavity. Adding cooling channels might run $1,500–$3,500. Making this explicit prevents scope creep and protects your margin.
Build a Quote Template with Real Data
Use a spreadsheet that includes:
- Part weight and material (resin type, color, additives)
- Mold cost (new, modified, or existing customer mold)
- Cycle time in seconds
- Estimated first-piece yield (how many shots before acceptable parts)
- Machine rate ($/hour)
- Secondary operations (trimming, ultrasonic welding, painting)
- Minimum order quantity (MOQ) and total units
- Lead time (mold build + production + QC)
- Contingency buffer (5–10%)
Price by Volume Tiers
Don't quote a single price. Show tiered pricing: 5,000 units at $0.68/part, 10,000 at $0.52/part, 25,000 at $0.41/part. This incentivizes larger orders and helps customers understand the unit economics. Your margin per part decreases with volume, but your total margin grows because fixed costs (mold amortization, setup) spread across more parts.
Account for Material Resin Volatility
Plastic resin prices swing 10–20% quarterly based on crude oil prices. If quoting a 90-day delivery, either lock in material cost with your supplier upfront or add a 5% material price adjustment clause to the quote.
Listing your services on platforms like Mercoly helps you reach customers actively searching for injection molding capacity, turning accurate quotes into closed deals faster.
Frequently Asked Questions
Q: How should I amortize tooling costs across production runs? Divide total mold cost by your expected total annual production volume on that tool, then add that per-part cost to each quote. If a $6,000 mold produces 50,000 parts per year, that's $0.12 amortization per part.
Q: What's a realistic first-article scrap rate I should budget for? Budget 5–15% scrap for the first 200–500 parts while dialing in gate location, cooling, and ejection; disclose this to the customer so they understand lead time includes approval cycles.
Q: Should I charge separately for engineering or design consultation? Yes—design reviews, tolerance analysis, and material selection should be $500–$2,000 as a separate consulting fee, credited back if they order production.
Get your next quote right: list your shop on Mercoly to connect with manufacturers and businesses actively seeking accurate, reliable molding partners.