Why price per kilogram is the only fair way to compare filament
Filament is sold in a confusing mix of sizes. One store lists a 500 g spool, another a 1 kg spool, and a third bundles three or four spools into a single pack. The number on the product page tells you what you pay at checkout, but not what you get for it.
The sticker price lies
A cheaper sticker price often just means a lighter spool. A 500 g spool at two-thirds the price of a 1 kg spool is not a deal, it is more expensive per gram of plastic you can actually print with. Multi-spool packs cut the other way: the total looks high, but the cost per kilogram can be the lowest on the page.
One number, fairly compared
Price per kilogram normalizes all of that. Every listing is divided by the plastic it contains, so a 500 g spool, a 1 kg spool, and a four-pack all line up on the same scale. Sort by it and the genuinely cheapest option rises to the top regardless of how the retailer chose to package it.
That is the whole idea behind filament.cool:
- Every listing is reduced to price per kilogram before it enters the table.
- Packs of different sizes rank against each other honestly.
- Shipping is called out when it is not already included, because it changes the real cost.
Start from the full price table, or jump straight to a material like PLA or PETG to see the cheapest spools by true cost.