Dog House Size: How Big to Build for Small to XL Dogs

A bigger dog house is not a better dog house. Picking the right dog house size means building just large enough for your dog to stand, turn around and lie stretched out, and no larger, because a dog warms its shelter with its own body heat. Too much empty air and the house stays cold in winter. Too little and your dog will simply refuse to use it.

The fastest way to get it right is to measure your dog rather than guess from breed charts. With three measurements and a few simple multipliers, you can size the door, interior floor and roof height for any dog from a small terrier to a giant breed.

Breed charts help when you are building for a growing puppy, but they are only averages. Two 70-pound dogs can differ by several inches in body length, and that difference decides whether a dog can lie stretched out or ends up sleeping half out of the doorway.

Dog House Size Formula: Measure Your Dog First

Get your dog standing on a level surface and use a soft tape measure. Take these three measurements:

1. Nose to base of tail (A): the body length, not including the tail.
2. Floor to top of head (B): standing height with the head in a natural position.
3. Floor to top of shoulder (C): the withers height.

Then apply these rules for dog house dimensions:

• Door height: about 75 percent of shoulder height (C). Dogs duck slightly to enter, and a smaller opening keeps out wind and holds heat.
• Door width: just wider than your dog’s chest at its widest point, usually 1 to 2 inches more.
• Interior length: about 1.25 times body length (A), so your dog can lie fully stretched.
• Interior width: roughly equal to body length (A), giving room to turn around.
• Interior height (lowest ceiling point): about 1.25 times standing head height (B). This lets your dog stand and sit up without bumping the roof.

For a dog that measures 30 inches nose to tail base, 26 inches to the top of the head and 22 inches at the shoulder, that works out to a door about 16 to 17 inches tall, an interior roughly 38 inches long by 30 inches wide, and a ceiling height of about 32 to 33 inches.

Dog House Size Chart by Dog Size

If you cannot measure (say you are building for a puppy that will grow), these dog house measurements are reasonable starting points based on typical adult sizes. Always check against your own dog when possible.

Heights in the chart refer to the lowest point of the interior ceiling. Peaked roofs add headroom in the center, which dogs appreciate but which does not count toward the minimum.

Sizing for Large and Giant Breeds

An xl dog house or x large dog house is where sizing mistakes get expensive, since lumber and roofing costs climb quickly. Giant breeds such as mastiffs, Great Danes and Newfoundlands often need an xxl dog house with interior length of 5 feet or more. A few extremely large dogs need what some sellers call a xxxl dog house, with interiors of 60 to 66 inches long and ceilings around 48 inches.

With dogs this size, the body-length rule matters most. Big dogs sprawl on their sides, legs extended, and a house that is a few inches short forces them to curl up uncomfortably or lie half out of the doorway. Measure your dog lying flat on its side, nose to back foot, and make sure the interior length covers that.

Two dogs sharing one house

If two dogs share a shelter, add about 50 to 75 percent to the floor area of the larger dog’s size, keep the ceiling height for the taller dog, and size the door for the bigger one. Many owners find two separate houses work better, since dogs often prefer their own space.

Door Placement, Floor Height and Weather Protection

Size alone does not make a shelter comfortable. Several design details matter just as much:

• Offset door: place the opening toward one end of the long wall rather than the center. Your dog can curl up in the protected far end, out of the wind.
• Windbreak wall: an interior partition or an entry vestibule blocks drafts further in cold climates.
• Raised floor: lift the floor 3 to 4 inches off the ground on treated runners or blocks. This keeps out ground moisture and cold, and lets air circulate underneath.
• Door flap: a heavy vinyl or rubber flap holds heat in winter. Train your dog to push through it.
• Roof overhang: extend the roof 3 to 6 inches past the walls to shed rain away from the door.
• Removable roof or wall: a hinged lid makes cleaning and bedding changes simple.

For cold regions, an insulated dog house with foam board in the walls, floor and roof keeps your dog far warmer than an uninsulated box of the same size. Insulation works best when the house is sized tightly, since a snug interior lets body heat do the work.

Building Steps for a Correctly Sized House

1. Measure and calculate. Record your dog’s three measurements and work out door, floor and ceiling dimensions.
2. Add material thickness. Exterior dimensions equal interior plus wall, insulation and floor thickness. With 3/4-inch walls and 1-inch foam, add about 3.5 inches to each overall dimension.
3. Build the floor frame. Use pressure-treated 2×4 runners on edge for the raised base, then sheath with exterior plywood.
4. Frame and sheath the walls. Cut the door opening per your calculation and round or sand the edges so they will not catch fur or skin.
5. Insulate if needed. Fit rigid foam between framing and cover it fully with an inner plywood layer so your dog cannot chew it.
6. Add the roof. Pitch it to shed water, cover with roofing felt and shingles or metal, and include the overhang.
7. Finish and ventilate. Paint or stain the exterior with a pet-safe, low-VOC product and let it cure fully. Add small vents high on the gable ends for summer airflow.

Troubleshooting a Dog House Your Dog Won’t Use

• Dog lies in the doorway: the house is too short. Your dog cannot stretch out inside.
• Dog avoids it in winter: the house is too large to hold heat, or the door faces the prevailing wind. Turn it, add a flap, or build a partition to shrink the sleeping area.
• Dog avoids it in summer: it overheats. Move it into shade, add vents and lift it further off hot ground.
• Bedding stays damp: the floor sits too close to the ground or the roof leaks. Raise the base and check flashing.
• Dog seems nervous going in: introduce it gradually with treats, a favorite blanket and positive praise.

General Cost Ranges

A simple DIY house for a small or medium dog usually costs under a couple hundred dollars in plywood, framing and roofing. Large and XL builds with insulation and shingles often reach a few hundred dollars in materials. Prebuilt houses range from inexpensive plastic shells for small dogs to several hundred dollars or more for insulated XXL models with raised floors and doors.

When to Call a Pro

Most dog houses are straightforward DIY projects. Consider hiring a carpenter for oversized or custom builds, such as a house with a porch, a heated floor or an attached kennel run. If you want a heated pad or a fan powered from the house, use products rated for outdoor and pet use, and have any new outdoor outlet installed by a licensed electrician with GFCI protection.