Valuation
The formula behind every scrap price
Before you negotiate anything, it helps to have your own number, not just the one the other side gives you. Here's the actual formula buyers use, so you can run it yourself before a conversation starts, not during it.
The problem
"I have no idea if this number is fair or just convenient for them"
"I don't even know what number I'm supposed to expect. Whatever they say sounds plausible because I have nothing to compare it to."
You don't need industry experience to have a defensible estimate. You need three inputs and a formula anyone can run in a minute.
The formula
Weight × Price per unit weight × Purity adjustment = Estimated value
This is the same basic calculation a buyer runs internally before naming a number to you.
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Weigh or estimate your material
A bathroom or luggage scale works for smaller loads. Larger loads may need a weighbridge, or an estimate based on similar known weights.
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Check the current price for your category
Live material pricing gives a current reference rate per unit weight for your specific material category, not a generic average across all metals.
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Adjust down for purity and contamination
Clean, sorted material sells closer to the reference rate. Mixed, rusted, or contaminated material is typically discounted, sometimes significantly, to account for the buyer's own cleanup or sorting cost.
A worked example
50 kilograms of clean, sorted copper wire
| Weight | 50 kg |
| Reference rate (example only, check live pricing for today's actual rate) | per kg |
| Purity adjustment for clean, sorted wire | Minimal discount |
| Rough estimate | Weight × today's rate |
50 kilograms of mixed copper wire with insulation still attached
| Weight | 50 kg |
| Reference rate | Same base rate as above |
| Purity adjustment | Larger discount, insulation reduces usable copper content and adds buyer prep work |
| Rough estimate | Noticeably lower than the clean example |
The point isn't the specific numbers, which change daily and by material. It's that the same weight of the same base metal can reasonably sell for very different amounts depending on condition, and that gap is explainable rather than arbitrary.
Run this formula with today's actual numbers for your material category.
Check live rates nowThe honest limitation
"My estimate and their offer don't match. Who's right?"
Probably both of you, to a point
Your estimate is a starting reference based on a clean, ideal version of your material. A buyer's offer reflects the actual condition in front of them, plus their own costs and margin. A small gap between the two is normal and explainable. A large, unexplained gap is worth questioning, or worth checking against a second buyer's offer, which is exactly what a fixed-price listing visible to multiple buyers, or a live auction, lets you do without extra effort.
Frequently asked questions
What is the basic formula for scrap metal value?
Weight multiplied by the current price per unit weight for that material category, then adjusted down for contamination, mixed content, or lower purity. It's a starting estimate, not an exact figure a buyer is bound to.
Why does my estimate never quite match what a buyer offers?
Because your estimate is based on a reference price for clean, sorted material, and most real loads have some contamination, moisture, or mixed content that a buyer discounts for. The gap between your estimate and their offer is usually explainable, not arbitrary.
Should I trust my own estimate over what a buyer tells me it's worth?
Trust your estimate as a reference point, not a guarantee. If a buyer's offer is dramatically below what a reasonable estimate suggests, it's worth asking why, or checking a second buyer's offer, rather than assuming your number was wrong.
Does ScrapTrade have a tool that does this calculation for me?
Yes. Live material pricing and the scrap price calculator on ScrapTrade give a current reference figure by category, which does the weight-times-rate part of the estimate for you.
Get a real number before your next conversation
Check live rates for your material, then list it or walk into a negotiation already informed.
Related reading: Negotiation tips · Free scrap metal guide · Scrap material categories