About this site

3D printing has a pricing problem that storage and memory solved years ago: nobody shows you the unit price. Filament is sold in 250 g mini spools, 1 kg standards, 2.2 kg bundles and 5 kg multipacks, at prices that only make sense once you divide. A "40% off" badge on an overpriced spool beats a cheaper spool at full price in every listing Amazon shows you, and loses on the only measure that matters.

So this site does the division. Every filament listing we track is ranked by cost per kilogram, every resin by cost per litre, with bundles counted at their total weight so a four-pack competes fairly with a single roll.

Where the data comes from

Prices, price history and discount figures come from the Keepa API, which tracks Amazon pricing over time. Weights, materials and pack counts are parsed from the product titles themselves. Where a title does not state a usable weight, we leave the per-kilo figure blank rather than guess — a confidently wrong ranking is worse than an honest gap.

What else is here

• Printers, parts and scanners have no per-unit measure worth ranking on, so they are listed by Amazon sales rank, with a filter for what is on offer today.
• Best-seller pages rank products by where they actually sat in Amazon’s sales chart through each year.
• Printer reviews are desk research, not hands-on testing. Their ease-of-use and reliability scores are calculated from specifications, documented issues and Amazon buyer ratings, and every review shows the workings.
• The printer finder recommends from those reviewed printers, using a fixed points table, your answers and today’s prices.

What we do not do

We do not accept payment for placement, and no ranking, score or recommendation here takes commission into account: how we rank sets out every rule. We hold no stock, take no orders and handle no payments; every purchase happens on Amazon.