You can make a functional litter box from a plastic storage container, a cardboard box, or even a large plastic bin—all for less than the cost of a commercial one

A DIY litter box works just as well as a store-bought model if you choose the right base material and size it properly for your cat. The simplest version uses a plastic storage container with one side cut down so your cat can climb in and out. You'll need a container at least 15 inches long, 10 inches wide, and 5 inches deep for an average cat—larger if you have a big breed or multiple cats sharing one box.

The main advantage of building your own is cost and customization. You can make the entry height exactly right for an older cat with mobility issues, use a container that fits your space better than standard boxes, or build multiple boxes cheaply if you have several cats. The trade-off is that you spend time on construction and may need to replace the container sooner than a commercial box would last, since plastic degrades over time with litter moisture and cat urine.

Key Takeaways

  • A plastic storage container, cardboard box, or large plastic bin can serve as the base for a working litter box with minimal modification.
  • The box needs to be at least 15 inches long, 10 inches wide, and 5 inches deep, with an entry cut down to 4 to 5 inches high so your cat can step in easily.
  • You'll need a utility knife or box cutter, sandpaper or a file to smooth rough edges, and litter—the same litter you would use in any box.
  • A plastic liner or waterproof layer inside the container extends its life by protecting the material from moisture and urine damage.
  • Most DIY boxes need litter replacement every 1 to 2 weeks and container replacement every 1 to 3 years depending on material thickness and use.

Choosing the right container for your base

Plastic storage containers work best because they're waterproof, straightforward to cut, and widely available. Look for a clear or opaque plastic bin at a hardware store, discount retailer, or online—the kind used for under-bed storage or seasonal items. Avoid thin, flimsy plastic that bends easily; aim for containers at least 1/8 inch thick. A 20-gallon or larger container is ideal for one cat; use a 30-gallon or bigger if you have two cats or one very large cat.

Cardboard boxes work in a pinch and cost nothing if you have one on hand, but they deteriorate quickly once exposed to moisture. If you use cardboard, line it heavily with plastic sheeting or a garbage bag to extend its life to a few weeks. Large plastic storage bins, the kind used for laundry or garage storage, are durable and often cheaper per gallon than smaller containers.

Avoid containers that held chemicals, pesticides, or anything toxic. Even after washing, residue can harm your cat. Food-grade containers are safe but unnecessary—regular storage containers work fine.

Cutting the entry and preparing the container

Mark the entry point on one side of the container, about 4 to 5 inches up from the bottom. This height lets most cats step in comfortably without having to jump high. For senior cats or those with arthritis, cut the entry even lower—2 to 3 inches. Use a utility knife or box cutter to cut a rectangular opening roughly 8 inches wide and 4 to 5 inches tall. Take your time; plastic can crack if you cut too fast or explore uneven pressure.

After cutting, sand or file the edges smooth with medium-grit sandpaper (80 to 120 grit) or a metal file. Rough plastic edges can cut your cat's paws or legs as they climb in and out. Wipe away dust with a damp cloth and let it dry completely before adding litter.

If you want to reduce litter tracking, you can cut a second, smaller opening on the opposite side of the container, about 1 inch from the bottom. This creates a "tunnel" entry that forces your cat to step up and over a lip, which helps shake litter from their paws before they exit. The second opening should be about 6 inches wide and 3 inches tall.

Lining the container to prevent leaks

A waterproof liner protects the plastic from urine damage and extends the container's life significantly. Use a heavy-duty plastic garbage bag, a plastic shower liner, or a waterproof tarp material. Drape it inside the container so it covers the bottom and sides, with extra material hanging over the rim. You can tape the edges to the outside of the container with waterproof tape, or straightforward tuck them under the rim so they stay in place.

Poke small drainage holes in the liner at the lowest point of the bottom if you want urine to drain out (useful if you plan to place the box on a concrete floor or in a garage). Otherwise, leave the liner intact so urine pools at the bottom, where you can scoop it out with the litter. Either way, the liner prevents liquid from soaking into the plastic itself.

Replace the liner every time you do a full litter change, or whenever it tears. A new garbage bag costs almost nothing and takes 30 seconds to swap out.

Adding litter and managing odor

Use the same type of litter you would in any box—clumping, non-clumping, clay, pine, paper, or crystal litter all work in a DIY box. Add 3 to 4 inches of litter to the bottom. Scoop out clumps daily, and do a full litter change every 1 to 2 weeks, depending on how many cats use the box and how much odor builds up.

If odor becomes a problem, add a layer of baking soda under the litter or sprinkle it on top of the litter before adding fresh material. You can also place a small open box of baking soda or activated charcoal next to the litter box to absorb airborne odors. Some people add a thin layer of newspaper or puppy pads under the litter to catch urine and make cleanup easier, though this is optional.

Ventilation matters more in a DIY box than in a commercial one, since there's no odor-control design built in. Place the box in a room with decent air circulation, away from your living areas if possible. A small fan nearby helps move air and reduce smell.

Dealing with litter tracking and splashing

Litter tracking—bits of litter stuck to your cat's paws and scattered around the house—is the biggest complaint with DIY boxes. A high-sided container naturally reduces this compared to a shallow pan, but you can do more. Place a litter mat or old towel in front of the entry so your cat steps on it as they leave; this catches loose litter before it reaches your floors.

If your cat splashes urine on the sides of the box, the plastic liner catches it. If splashing is severe, you can build a straightforward splash guard by taping a piece of plastic sheeting or a shower curtain panel to the inside back wall, extending it a few inches above the litter line. This is especially useful if your cat is male or tends to spray.

Some cats prefer a covered box, which also reduces tracking and odor. You can create a cover by cutting an entry hole in the lid of a large plastic storage container and placing it on top of your litter box base. Make sure the cover is removable or hinged so you can access the box easily for scooping.

When to replace your DIY litter box

A plastic container litter box typically lasts 1 to 3 years depending on the thickness of the plastic, how much urine it's exposed to, and how well you maintain the liner. Signs it's time to replace it include cracks in the plastic, permanent staining or discoloration that won't clean, a persistent smell even after cleaning, or visible wear on the edges where your cat climbs in and out.

Cardboard boxes need replacement every few weeks to a couple of months. Plastic liners should be replaced with each full litter change or whenever they tear. If you're replacing the container frequently, you might find that buying a commercial litter box becomes more economical over time—but if you're handy and have containers on hand, DIY remains the cheaper option.

Keep a spare container on hand so you can swap it out quickly if the current one fails. This prevents your cat from having no litter box while you build a replacement.

Frequently Asked Questions

Can I use a plastic bin without cutting an entry hole?

You can, but your cat will have trouble getting in and out, especially if they're older or larger. Cats need an entry they can step into comfortably. A hole cut 4 to 5 inches high is the standard; without it, your cat may refuse to use the box or injure themselves trying to climb over the rim.

What if the plastic container is too small for my cat?

Your cat needs at least 15 inches of length to turn around and dig comfortably. If your container is smaller, find a larger one—a 20-gallon or 30-gallon bin is better than struggling with something too cramped. A box that's too small often leads to cats going outside the box.

How do I keep the litter box from smelling bad?

Scoop daily, change litter every 1 to 2 weeks, use a waterproof liner to prevent urine from soaking the plastic, and place the box in a well-ventilated area. Baking soda under or on top of the litter also helps. If smell persists, you may be changing litter too infrequently or the box is in a space with poor air circulation.

Is a DIY litter box safe for my cat?

Yes, as long as you sand the cut edges smooth so they don't scrape your cat's paws or legs, and you avoid containers that held chemicals or toxins. Use food-safe or regular storage containers, not industrial bins. The box itself poses no danger once properly prepared.

Can I make a litter box from a cardboard box?

Yes, but it's temporary. Line it heavily with plastic sheeting or a garbage bag to protect the cardboard from moisture. It will last a few weeks to a couple of months before the cardboard softens and falls apart. Plastic containers are more durable and worth the small cost.