Our method for selecting comparable filament offers, calculating price per kilogram, dating snapshots, and separating price data from compatibility evidence.
Short answer: we rank only filament offers with a positive pack price, confirmed total net filament weight, a consistent material label, a supported USD currency and a retailer URL. We calculate price/kg from the pack price and net weight. The snapshot date describes when our source data was fetched, not the price at checkout.
Which offers can be compared?
- The item must be filament with an identified material. Mystery, random-choice and conflicting-material offers are excluded from material rankings.
- Pack price and total net filament weight must both be positive finite numbers. The spool and packaging are not filament weight.
- The currency must be USD or a recognized USD label, and the offer must link to the retailer listing.
- Shipping, tax, coupons, memberships, reusable spools and adapters are not included unless a page explicitly says otherwise.
How is price per kilogram calculated?
Price/kg = selected pack price ÷ total net filament kilograms. We calculate before display rounding. A four-spool pack containing four 1 kg spools uses 4 kg; a 500 g spool uses 0.5 kg. We show the full pack price beside the normalized unit price so a low unit price does not hide a larger upfront purchase.
What does the snapshot date mean?
Each comparison displays the source snapshot date when available. Prices can change after collection. When a snapshot is older than two expected refresh cycles, product pages keep the dated record but stop describing it as current or the current lowest price. This display rule does not change the collection schedule.
How do we assess compatibility claims?
Price inclusion does not prove printer or feeder compatibility. We distinguish manufacturer specifications, retailer claims, our calculations and hands-on testing. Model-specific manufacturer documentation is the preferred source for AMS dimensions and material limits. Unless a page explicitly documents a test, our comparisons are not hands-on tests.
How can an error be corrected?
Send the page URL, selected merchant variant and the disputed field through our contact page. We recheck the source and update the page date when editorial content changes. Retailer snapshots remain dated records rather than being silently presented as checkout quotes.
Use the method
Next step: Compare an offer's pack price, net weight and snapshot date, then verify the exact retailer variant before buying.
Affiliate disclosure: As an Amazon Associate, we earn from qualifying purchases.
Data disclaimer:Prices and availability may change. Always verify the final price on the retailer’s site before purchasing.