Most paper can be composted, but not all of it

Plain paper breaks down in a compost pile because it is made from plant fiber. Newspaper, cardboard, paper bags, and office paper all decompose within weeks to a few months, depending on how finely shredded they are and how wet your pile stays. The catch is that many papers contain inks, coatings, or chemicals that either slow decomposition or leave residue in finished compost.

The rule is straightforward: compost paper that was printed or made without synthetic dyes, plastic coatings, or bleach. Avoid anything glossy, anything labeled "non-recyclable," and anything that was in contact with food oils or grease. Shred larger pieces before adding them—a whole newspaper takes months, but shredded newspaper breaks down in weeks.

Key Takeaways

  • Newspaper, plain cardboard, kraft paper bags, and uncoated office paper all compost safely and speed up decomposition when shredded.
  • Glossy paper, coated cardboard, bleached white paper, and anything printed with colored inks should stay out of your pile.
  • Shredding paper into strips or small pieces cuts decomposition time from months to weeks and helps it mix evenly with other materials.
  • Paper that held food, grease, or wax—including pizza boxes and takeout containers—will not break down properly and can attract pests.

Paper that decomposes safely in compost

Newspaper is one of the best papers to add. Black ink is carbon-based and breaks down without leaving harmful residue. Shred it into strips about an inch wide and mix it throughout your pile rather than layering it in clumps. Wet newspaper compacts and slows air flow, so distribute it loosely.

Cardboard (plain, uncoated) works well if you remove tape, staples, and plastic windows first. Corrugated cardboard from shipping boxes takes longer than newspaper but still decomposes within a few months. Kraft paper bags—the brown grocery bags—are safe to compost whole or shredded. Tear them into pieces to speed things up.

Office paper (white or colored, printed with black or standard office ink) composts without issue. Shred it to increase surface area. Paper from inkjet or laser printers is fine; the inks are not toxic to soil microbes. Junk mail, envelopes without plastic windows, and printed flyers all belong in the pile.

Paper towels and napkins (unbleached or lightly bleached) break down quickly because they are already thin and designed to fall apart. Tissue paper does the same. These are useful for absorbing excess moisture in a pile that has gotten too wet.

Paper to keep out of your compost

Glossy paper has a plastic or wax coating that prevents decomposition. Magazines, brochures, and photo paper all have this coating. The shiny surface is the giveaway—if it feels slick or waterproof, leave it out. Glossy cardboard (like cereal boxes) falls into the same category.

Bleached white paper is not toxic, but heavy bleaching can slow decomposition and leave trace chemicals in your finished compost. If you have a choice between white office paper and unbleached kraft paper, the kraft paper will break down faster. Bright white paper is usually more heavily bleached than off-white or cream-colored paper.

Colored inks (anything printed in bright red, blue, green, or other vivid colors) may contain heavy metals or synthetic dyes that do not break down easily. Black and dark blue inks are safer. When in doubt, stick to newspaper and plain cardboard.

Food-contact paper is the biggest mistake people make. Pizza boxes, takeout containers, paper plates, and paper cups often have a wax or plastic lining on the inside to keep grease from soaking through. Even if the outside looks plain, the inside coating will not decompose. Greasy paper also attracts rodents and insects to your pile. If the paper is stained with oil or food residue, it does not belong in compost.

How to prepare paper for composting

Shredding is the single most important step. A whole sheet of newspaper can take three months to break down; shredded newspaper breaks down in three to four weeks. Tear or cut paper into strips about one inch wide, or run it through a paper shredder if you have one. Smaller pieces expose more surface area to moisture and microbes.

Wet the paper as you add it to your pile. Dry paper sits on top and blows away; damp paper mixes in and starts decomposing when ready. You do not need to soak it—just spray it with a hose or water can as you layer it with other materials.

Mix paper throughout your pile rather than stacking it in one spot. Paper compacts easily and can create an air pocket that slows decomposition. Alternate layers of paper with grass clippings, food scraps, or other green materials. A good ratio is roughly one part paper to two or three parts other compost materials by volume.

Why paper helps your compost pile

Paper is carbon-rich, which means it balances the nitrogen-rich materials (grass, food scraps, manure) that make up most home compost piles. A pile with too much nitrogen becomes slimy and smells like ammonia. Adding shredded paper absorbs excess moisture and creates air pockets that keep the pile aerobic (oxygen-rich), which speeds decomposition and reduces odor.

Paper also provides bulk and structure. A pile made only of food scraps and grass clippings compacts into a dense, airless mass. Paper fibers help keep the pile loose and open, allowing air to flow through. This is especially useful if you live in a wet climate or if your pile tends to get soggy.

Common mistakes to avoid

Do not add paper that is wet or moldy before it goes in the pile. Wet paper from rain or a sink will introduce excess moisture and may already be colonized by mold that will slow decomposition. Let wet paper dry first, or add it in small amounts mixed with dry materials.

Do not layer paper thickly. A layer of newspaper more than half an inch thick will compact and create an anaerobic (oxygen-free) zone. Thin layers mixed throughout the pile work much better.

Do not assume all cardboard is safe. Waxed cardboard (like milk cartons or frozen food boxes) and plastic-lined cardboard (like some produce boxes) will not decompose. If you are not sure, check the inside surface—if it feels slick or plastic-like, leave it out.

Frequently Asked Questions

Can I compost paper with colored ink?

Black and dark blue inks are safe. Bright colored inks (red, green, yellow) may contain synthetic dyes or heavy metals that do not break down. When in doubt, stick to newspaper and plain cardboard. A small amount of colored ink will not harm your compost, but it is better to avoid it if you can.

Is it okay to compost shredded junk mail?

Yes, as long as it does not have a plastic window or coating. Remove any plastic windows or envelopes with plastic linings before shredding. The paper itself breaks down safely. Avoid anything labeled "non-recyclable" or anything that feels slick or waterproof.

How long does paper take to decompose in compost?

Shredded newspaper breaks down in three to four weeks in an active, warm pile. Whole newspaper takes two to three months. Cardboard takes one to three months depending on thickness and how wet the pile is. Thinner, wetter piles decompose faster than thick, dry ones.

Can I compost paper bags that held food?

Only if they held dry food and have no grease stains. Paper bags that held flour, sugar, or bread are fine to compost. Bags that held oily foods, nuts, or anything greasy should stay out—the oil prevents decomposition and attracts pests. When in doubt, throw it in the trash.

What should I do with glossy magazines?

Glossy magazines do not belong in compost because the coating prevents decomposition. Recycle them instead if your local program accepts magazines. If recycling is not an option, they can go in the trash. The glossy coating is designed to last, so it will not break down in your pile.