How to Read and Compare Injection Molding Quotes: A Buyer’s Guide

I’ve reviewed thousands of RFQs across three continents, and here’s what I can tell you: the lowest quote is rarely the cheapest. It’s not that suppliers inflate prices. It’s that quotes hide important variables behind line items that look the same — but aren’t.

You might see $12,000 from Supplier A and $18,000 from Supplier B. Sounds like Supplier A wins, right? Not if they’re quoting a lower steel grade, skipping critical features, or excluding services that Supplier B includes. I’ve seen that trap spring more times than I can count.

Let’s walk through every section of a typical injection molding quote — and the ten red flags that separate professional partners from the rest.

Tooling Cost Breakdown

The tooling line item is the biggest single cost, and it’s where the most hidden variation lives. A professional quote breaks it down:

Cavity Count: Single-cavity tools run $8,000-15,000 for a typical part. Four-cavity tools jump to $15,000-28,000. The per-cavity cost drops with more cavities (economies of scale in machining), but the total goes up. Simple enough — but make sure the cavity count matches your actual volume needs. A 4-cavity tool for a 5,000-unit annual program is wasted capital.

Steel Grade: P20 is standard for prototype and low-volume tools. H13 hardened costs 20-30% more but lasts 5-10x longer. You need to know which grade they quoted. If the line item just says “mold steel,” ask for the specific AISI or DIN designation. Don’t let them be vague.

Cooling System: Conformal cooling channels add 25-40% to tooling cost but cut cycle time by 15-40%. Here’s what that means in real money: on a 30-second cycle part run at 100,000 units, a 20% cycle reduction saves roughly $3,000-6,000 in machine time. The quote should specify cooling type — straight drilled, conformal, or baffles.

Side Actions / Lifters: Every undercut feature — side hole, snap tab, internal thread — needs a sliding mechanism. Each action adds $1,500-5,000. If the quote doesn’t list side actions by count, the engineering is incomplete. Full stop.

Per-Part Pricing Curve

Always — always — request pricing at multiple volumes, not just your target quantity. A supplier’s pricing curve tells you a lot about their cost structure and production efficiency.

Here’s what to watch for: the per-part price should decline at a decreasing rate. If the price drops linearly — or doesn’t drop at all above 10,000 units — the supplier has built inefficiency into their curve. That’s a red flag.

Material Cost vs. Markup

Material typically makes up 30-50% of your per-part cost. A transparent quote lists the specific resin grade, supplier, and current market price. Ask these questions:

• Is the resin priced at spot market or contract rate?
• Is there a material markup, and what percentage?
• Can I supply my own resin?
• How is regrind handled — is it allowed, or does the quote assume virgin-only?

Most molders add 10-25% markup on resin. That’s reasonable if it covers material certification documentation, storage, and drying. But it needs to be disclosed.

Surface Finish and Cosmetic Upcharges

The SPI surface finish system defines nine levels from mirror polish to coarse EDM. Each grade costs differently:

• SPI-A1 (mirror polish, no blemishes): +20-35% over standard
• SPI-B1 (fine grit, brushed): +10-20%
• SPI-C1 (600 grit stone): standard (baseline)
• SPI-D1 (dry blast texture): +15-25%

Here’s the thing: if your quote doesn’t specify SPI grade, you’ll get whatever the mold maker delivers by default — typically C1 to C2. That might be fine, or it might be a nasty surprise. Get it in writing.

Secondary Operations

Here’s where costs can double on you. Many parts need operations after molding that add up fast:

• Pad printing: $0.05-0.20 per color per part
• Laser engraving: $0.10-0.30 per part
• Ultrasonic welding: $0.15-0.40 per weld
• Heat staking: $0.08-0.25 per insert
• Assembly (manual): $0.20-1.00 per assembly
• Packaging (blister pack): $0.10-0.30 per part

If you see “secondary operations quoted separately,” that’s a red flag. Ask for all-in pricing before you compare.

The 10 Red Flags

1. Vague line items — “Mold: $15,000” with no steel grade, cavity count, or cooling type
2. Zero DFM or Moldflow included — means no engineering review before cutting steel
3. No certification documentation — they can’t or won’t provide material certs or C of C
4. Unrealistic lead times — a 2-week tool for a complex 4-cavity mold means shortcuts
5. Missing payment terms — no deposit schedule, no milestone structure
6. Reluctance to provide references — unwilling, or they need “permission”
7. Unclear revision handling — no stated policy for engineering changes after quote acceptance
8. No quality guarantee — first article inspection report not included in scope
9. Non-standard warranty — mold warranty under one year or 500,000 cycles
10. Arbitrary MOQ — a minimum order that seems unrelated to part size or material

Questions to Ask Every Supplier

Before you accept any quote, get written answers to these:

1. What’s the exact steel specification and cavity count for the quoted tooling?
2. Is DFM and Moldflow analysis included or charged separately?
3. What’s the per-part price at my current volume AND at 2x and 5x that volume?
4. What SPI surface finish grade is assumed?
5. What secondary operations are included vs. priced separately?
6. What are the mold warranty terms — duration, cycle count, covered defects?
7. How are engineering changes priced after the quote is accepted?
8. What documentation is included — material certs, FAIR, CMM reports?
9. What are the payment terms and milestone schedule?
10. Can I speak with two current customers for reference?

A transparent quote is the foundation of any good molding partnership. Send CorelMould your RFQ and get a complete line-item breakdown with free DFM analysis included. Learn about our full range of injection molding services.