What is a #4 Coffee Filter? | Conical Size For 8-12 Cup Brewers

A #4 coffee filter is a large conical paper filter designed for 8–12 cup drip coffee makers and pour-over systems, providing the volume needed for full carafes without collapsing.

Buying the wrong coffee filter size is a fast way to ruin a pot. A #4 cone filter fits standard home drip machines and large pour-over brewers, but the numbering system can be confusing. This guide covers the dimensions, the machines that use it, and the simple steps to make sure your filter sits right and your coffee extracts properly.

How Big Is a #4 Coffee Filter?

A #4 filter measures roughly 5 inches (12.7 cm) tall with a top opening of about 7.5 inches (19 cm) wide. The conical shape narrows to a pointed tip, which directs water flow evenly through the coffee bed. Most packs contain 40, 80, or 100 filters and cost between $3.59 and $8.00 depending on the brand and count.

The name “1×4” you might see on European packaging (especially Melitta) doesn’t mean the filter holds four cups of water. That label refers to a single fill producing roughly four small European cups (125 ml each). The physical filter still fits 8–12 cup brewers sold in the US.

Which Coffee Makers Use a #4 Filter?

Any standard electric drip machine rated for 8 to 12 cups uses a #4 cone filter. This covers brands like Mr. Coffee, Krups, and many home brewers. Large pour-over systems like Chemex (8–10 cup models) and Funnex also take the #4 size. Smaller 2–6 cup machines use a #2 cone filter instead, and single-cup brewers use a #1.

Flat-bottom (basket) coffee makers do not use numbered cone filters at all — they require a different flat-bottom paper that fits by diameter. If your machine has a basket-shaped holder, the #4 will not seat properly.

How To Use a #4 Coffee Filter Correctly

The fit of the filter matters as much as the grind. An undersized #2 filter will collapse in a #4 holder, blocking water flow and producing bitter or weak coffee. Follow this sequence for a clean brew.

1. Confirm your brewer’s rating — check the markings on the carafe or the manual. If it says 8–12 cups, the #4 is the right size.
2. Open the filter — unfold the flat triangle and push the center crease so it opens into a round cone with the pointed tip hanging down.
3. Insert it into the holder — the tip should reach the bottom of the cone basket and sit snugly against the sides.
4. Check for a seal — run your finger around the rim to ensure the filter paper presses evenly against the plastic or metal. Any gap can let water bypass the grounds or leak into the machine’s base.
5. Add grounds — use about 1–2 tablespoons per cup. The #4’s extra space allows water to flow evenly, so the coffee bed extracts consistently.

The filter should hold its shape without sagging. If it collapses, the seal is wrong or you’re using a #2. If you are ready to buy the right size, our tested roundup of the best 4 coffee filters covers the top models with verified dimensions.

Common Mistakes With #4 Filters

Three errors cause most of the frustration with cone filters. The first is putting a #2 filter into a #4 machine — the short paper can’t reach the walls of the holder, so it buckles and clogs. The second is assuming “1×4” means the filter is only for four cups, which leads people to a wrong size. The third is using a #4 cone filter in a flat-bottom basket brewer; cone and basket filters are not interchangeable, and the shape difference guarantees a messy overflow.

Material and Safety Notes

Most #4 paper filters are made from dioxin-free, chlorine-free paper. Unbleached (natural brown) varieties are processed without bleach, while white ones are oxygen-bleached. Both are safe for hot water use. If You Care and Melitta both offer unbleached versions that are totally chlorine-free (TCF). These filters are biodegradable and compostable, so they can go into the bin with the coffee grounds for simple disposal.

Some filters contain recycled paperboard. Check the packaging if you prefer a specific material — most brands list whether the filter is oxygen-bleached or unbleached.

Checklist: Confirm Your Filter Is Right

One way to avoid guessing is to check your holder. Take the old filter out — if it is a tall cone with a point at the bottom, you own a cone machine and need a #4 if the brewer is 8–12 cups. The filter should sit flat against the walls with no folds or gaps. When water hits the grounds, the filter should stay upright and not collapse. If it does, you either have the wrong size or the holder is warped.

This is the same test whether you use an electric drip machine or a manual pour-over. A proper fit makes extraction predictable and cleanup simple — the used filter lifts out in one piece with the grounds inside.