Interior Door Installation Cost Calculator

Hollow or solid core is a sound decision, not a looks decision

From across a room you cannot tell them apart. They are usually the same molded skin with the same panel profile, hung the same way, in the same time. The difference is what is inside, and what that does to noise.

• A hollow core door is two thin skins over a cardboard honeycomb. It weighs about 25 pounds, it sounds hollow when you knock it, and it transmits a conversation at normal volume through to the hall.
• A solid core door is the same skin over an engineered wood core. It weighs 60 to 90 pounds, it sounds like a wall, and it stops ordinary speech.

$204 a door is the best-value upgrade in the whole door cluster, and it is worth being selective rather than uniform about it. The doors where it earns its money:

• Bedrooms off a living area, especially where somebody sleeps at a different time from everybody else.
• A home office or anywhere a call happens.
• Bathrooms, for obvious reasons.
• Any door on a shared wall in a duplex or a converted house.

The doors where hollow core is perfectly fine: closets, a pantry, a laundry, a basement stair. There is no rule saying every door in the house has to match in construction — only in appearance, and that is the skin, which is the same.

Solid wood is a third thing: stile-and-rail construction in actual lumber, at $1,025 for one door. It is the best looking, it is the only one that takes a stain properly, and it is the only one that can be planed and refinished indefinitely. In a period house with original trim it is the right answer; in a 1990s builder house it is money spent where nobody will notice.

The bare slab is not the saving it looks like

The obvious economy is to buy just the door — a slab — and hang it in the frame that is already there. It saves about 5%, and here is why so little:

A slab is $50 to $70 cheaper than the pre-hung unit. But a pre-hung door arrives with its hinges already mortised into both the door and the jamb, the frame square, and the whole thing ready to shim into the opening. A slab has to have its hinges mortised to match the existing jamb exactly, its lock bored, and its edges planed to an opening that in most houses is not square — and that work costs most of the saving back.

Buy a slab when you want to keep the existing frame and casing, which is a good reason in a house with original trim worth preserving. Do not buy one to save money.

Do the whole house at once

This runs the opposite way from exterior doors, and it is worth knowing:

A quarter cheaper per door at six than at one. The reason is that load-in, floor protection and hauling the old doors away happen once on a job where the doors themselves are cheap — so the fixed share is large. On an exterior door, where the unit is $850 or more, the same fixed cost barely registers and batching saves about 10%.

So if you are replacing interior doors, replace them together. A typical three-bedroom house has six to nine once the bathrooms, the closets and the basement stair are counted.

Primed is not painted

A pre-hung interior door arrives primed. Primed is a surface waiting for paint, not a finish — it will mark, it will not clean, and it looks exactly like what it is.

Painting is two coats on both faces, both long edges and the casing, which on six doors is a day's work and about 20% on the job. It is the single line most often assumed to be in a quote when it is not. Ask directly: are these being painted, and is that in the price?

Three other things about the finish:

• Factory-finished doors exist and are worth pricing. The finish is better and more durable than site-painted, and the doors arrive done.
• Spray beats brush on a door, visibly. If they are being painted on site, ask whether they will be sprayed.
• Staining is only an option on solid wood. It does not work on a molded skin, whatever the skin is pretending to be.

Measure before you order anything

Interior doors come in standard widths — 24, 28, 30, 32 and 36 inches — at 80 inches tall. Three things catch people out:

• The door size is not the opening size. A pre-hung unit needs a rough opening about two inches wider and two and a half inches taller than the door itself, for the frame and the shim space.
• Older houses are not standard. Pre-1950 houses frequently have 26 or 27 inch doors, taller openings, and frames that are visibly out of square. A pre-hung unit will not fit those without reframing, so the realistic options are a slab planed to fit, or a custom unit.
• Handing. Which side the hinges are on and which way the door swings. Stand in the opening facing the door as it swings away from you: hinges on the left is a left-hand door. Getting this wrong on a pre-hung order means a restocking fee and a delay, and it is the commonest ordering mistake there is.

Also: if new flooring is going in, do the flooring first or allow for it. Doors need a clearance of about half an inch over the finished floor, and a door that was fine over the old vinyl will drag on new carpet.

The two code points worth knowing

• The garage-to-house door must be fire-rated in most jurisdictions — typically a 20-minute rating — and in many it must be self-closing. It is not an ordinary interior door, it costs more, and it is not optional. If a quote treats it as one of the batch, ask.
• Bathroom and bedroom doors need privacy sets, not passage sets, and a privacy set has an emergency release on the outside. Worth confirming, because the difference is a few dollars and people notice it immediately.

What this page does not price

Four common interior doors are different jobs:

• Pocket doors, which slide into the wall. The frame kit goes inside the stud bay, so it means opening up the wall — $1,000 to $2,500 a door in an existing wall and much less during a remodel when the wall is already open.
• Bifold doors, usually on closets. Cheaper than a hung door at $150 to $400 installed, and a track job rather than a framing one.
• Barn doors, which hang on exterior track. The hardware is $150 to $500 and the real requirement is a clear run of wall as wide as the door, plus blocking behind the drywall to carry the rail.
• Interior French pairs, which are a glazed pair between rooms — the look of French doors without any of the weather detailing.

What you are paying for

For six hollow core pre-hung doors into existing openings, left primed, at $2,225:

Labor is about a third of it, which is why batching helps so much — and why the material decision, at $204 a door between hollow and solid core, moves the total more than anything else on the page.

Questions worth asking

• Hollow or solid core, and on which doors? You can mix.
• Pre-hung or slab, and if slab, why?
• Are they being painted, and is that in the price? Sprayed or brushed?
• Have the openings been measured, and are they square?
• What handing, door by door?
• Is new flooring going in first?
• Is the garage door fire-rated and self-closing?
• Privacy sets on the bathrooms and bedrooms?
• Levers or knobs? Levers are easier for arthritic hands and cost the same.
• Is the old door removal and disposal included?