$10,000 – $35,000That is the typical bathroom addition cost in 2026, with a national average of $20,000 (Fixr). This Old House is higher, at $21,000 to $49,000 on average. By type, Fixr runs from $5,000 to $15,000 for a half bath to $25,000 to $100,000 or more for a primary bath. Turning space you already have into a bathroom costs about half as much as building a new room for it.
This guide is about putting a bathroom where there was none: a half bath under the stairs, a full bath in the basement, a primary suite over the garage. It is not the same as our guide to bathroom remodel cost, which prices fixtures and finishes in a bathroom you already have, and it is narrower than home addition cost, which prices whole rooms. A new bathroom adds two big items a remodel does not: new drain, vent and supply lines, and, if you build out, new floor area.
Bathroom addition cost by type
| Type | Fixr (Jan 2026) | Block Renovation (Jul 2026) | Bob Vila (older, Feb 2023) |
|---|---|---|---|
| Half bath or powder room | $5,000 – $15,000 | $5,000 – $15,000 | $5,000 – $30,000 |
| Three-quarter bath | $10,000 – $22,000 | — | $5,000 – $18,000 |
| Full bath | $15,000 – $35,000 | $15,000 – $35,000 | $7,000 – $30,000 |
| Jack and Jill | $20,000 – $50,000 | $20,000 – $40,000 | — |
| Wet room | $10,000 – $40,000 | $10,000 – $50,000 | — |
| Primary bath | $25,000 – $100,000+ | $35,000 – $75,000 | $20,000 – $96,000 |
Fixr and Block Renovation agree for half and full baths and differ on the primary bath, where Bob Vila’s older range is wider than both. HomeLight, which compares the guides, reports that HomeGuide puts a new bathroom addition at $20,000 to $75,000 and converting existing space at $5,000 to $25,000 (HomeLight, updated July 1, 2026). Angi, in the same roundup, gives $5,000 to $75,000 for a new bathroom addition. So the top of the market is far higher than the typical range suggests.
Estimate your bathroom addition cost
Our estimate: the published ranges above multiplied out for your inputs. Not a quote. Bathroom ranges from Fixr (January 2026); permits from Fixr; architect fees from HomeLight (July 2026); ejector pump from Todays Homeowner (April 2025); labor share of about 50% from Fixr. The type ranges already include permits and plumbing, so add the extras only if your quote lists them separately. State adjustment: BLS construction wages (May 2025), applied to an assumed 50% labor share. How we calculate
Converting space vs building a new room
The biggest choice is whether the bathroom goes inside walls that already exist. Fixr prices converting existing space at $200 to $250 per square foot and building a new addition at $400 to $550. This Old House says the same: conversion costs up to 50% less, and a new addition is roughly twice the cost.
| Bathroom size | Convert existing space | Build a new addition |
|---|---|---|
| 35 sq ft (5 x 7) | $7,000 – $8,750 | $14,000 – $17,500 |
| 50 sq ft (5 x 10) | $10,000 – $12,500 | $20,000 – $27,500 |
| 60 sq ft (6 x 10) | $12,000 – $15,000 | $24,000 – $33,000 |
| 100 sq ft (10 x 10) | $20,000 – $25,000 | $40,000 – $55,000 |
This Old House, using Homewyse data, gives a different picture by size: $18,000 for a 25 sq ft half bath, $21,000 for a 50 sq ft full bath and $28,000 for a 100 sq ft primary bath (This Old House, updated June 12, 2026). Our reading is that the half bath costs almost as much as the full one because the plumbing, permit and framing costs barely change with size. The guides do not say so directly.
Cost by where the bathroom goes
| Location | Fixr (Jan 2026) | Block Renovation (Jul 2026) |
|---|---|---|
| Closet | $5,000 – $15,000 | $8,000 – $15,000 |
| Laundry room | $5,000 – $19,000 | $7,000 – $14,000 |
| Garage | $8,000 – $25,000 | $10,000 – $25,000 |
| Attic | $8,000 – $35,000 | $15,000 – $40,000 |
| Basement | $10,000 – $50,000+ | $8,000 – $20,000 |
| Bedroom | $15,000 – $50,000 | $10,000 – $25,000 |
| New addition | — | $20,000 – $50,000+ |
Closets, laundry rooms and bedrooms are cheapest when a drain stack is close by. Basements and attics cost more when pumps, structural work or long pipe runs are involved. For the basement, see also basement finishing cost. A bump-out, which pushes an exterior wall out to make room, is priced as a new addition. Fixup First puts a full bathroom bump-out at $40,000 to $100,000 or more (Fixup First, updated May 18, 2026), a smaller cost blog whose own pages give some inconsistent ranges, so treat it as one data point.
Why plumbing distance sets the price
| Where the new bathroom sits | Plumbing rough-in cost |
|---|---|
| Back-to-back with an existing bathroom | $1,500 – $3,500 |
| Directly above an existing bathroom | $2,000 – $5,000 |
| 10 to 20 ft from the stack | $3,000 – $7,000 |
| 30 to 50 ft from the stack | $6,000 – $14,000 |
| No nearby stack (new drain to the main sewer) | $8,000 – $18,000 |
Fixup First says placing the bathroom back-to-back with existing plumbing costs 40% to 60% less than running all-new lines. The bigger guides agree on the principle without a table. HomeLight lists rerouting a single plumbing line at $650 to $1,500 and new plumbing at $230 to $5,500 per fixture. This Old House says nearly one-third of the homeowners it surveyed reported unplanned plumbing upgrades, and that larger drain and vent lines may be needed.
Below the sewer line, gravity will not carry waste out. A sewage ejector pump lifts it, and Today’s Homeowner (updated April 11, 2025) puts the national average at $1,200 to $4,000 installed (about $2,500 for a typical job), and up to about $6,500 for a first-time install that needs new drain lines and concrete drilling. Bob Vila’s older guide gives $720 to $1,350 for installing a sewer-ejector system. If the new drain has to reach the main sewer line, see sewer line replacement cost for the price of a run that long.
Permits, plans and code
Fixr puts permits and inspections at about 3% of the total, around $500 on average and up to about $2,000 for an add-on. HomeLight says building permits run $500 to $2,500, and This Old House says at least $100, depending on location. Fixr lists an interior designer at $50 to $450 an hour, and HomeLight gives $2,190 to $11,550 for an architect. Bob Vila’s older guide says a permit is needed for a new bathroom.
Code decides how small a bathroom can be. In a February 2026 interpretation of North Carolina’s residential code, the state fire marshal’s office says the 21 inches of clear floor in front of a toilet must have a ceiling of at least 6 feet 8 inches over its full width, even under a sloped ceiling (NC Office of the State Fire Marshal). That is one state’s reading of its 2018 code, which is based on the International Residential Code; your state or county may use another edition, so ask your building department. It matters for under-stair and attic bathrooms with sloped ceilings.
One real example from HomeLight: a bathroom addition under an existing roof cost $26,150 in total, including $3,400 for plumbing, $1,300 for electric, $2,600 for HVAC and $2,700 for design and permits (HomeLight, contractor Andrew Holmes of Blockhouse Residential). A new bathroom may also need panel capacity; see electrical panel upgrade cost.
Labor and who to hire
Labor is about half the bill. Fixr says about 50%, and This Old House says 40% to 55%, with general contractor overhead and profit adding 15% to 25%. Both put plumbers at $75 to $150 an hour. Fixr lists electricians at $70 to $130 an hour and tile installers at $8 to $14 per square foot. Because a new bathroom needs plumbing, electrical and framing, a general contractor usually coordinates the trades; read how to find a contractor before you sign.
Does adding a bathroom pay off?
Less than a remodel does. According to the 2025 Cost vs. Value report, a midrange bathroom addition recoups about 53% of its cost at resale and an upscale one about 36%, while a midrange remodel of an existing bathroom recoups closer to 80% (This Old House; Fixr also gives 53%). HomeLight reports the midrange addition at a job cost of $60,645, far above the typical $15,000 to $35,000 for a full bath. The guides do not reconcile the gap; our reading is that the report prices a fully built room, not a conversion.
HomeLight quotes an agent who says adding a full bath to a one-bath home adds $20,000 to $25,000 in value, and says an appraisal adjusts $7,500 to $10,000 for adding a bathroom to a home that already has two or more. That is one agent’s view, not a measured figure. Build a bathroom for the daily use, not the payback.
How to keep the bill down
- Put the bathroom back-to-back with, or directly above, an existing bathroom. Fixup First says this saves 40% to 60% of the plumbing cost.
- Convert a closet, laundry room or spare bedroom instead of building out. Fixr prices conversion at $200 to $250 per square foot against $400 to $550 for an addition.
- Consider a half bath. Fixr and Block Renovation both put it at $5,000 to $15,000, against $15,000 to $35,000 for a full bath.
- Keep fixtures at stock sizes. Fixr says the shower or tub, and the vanity with countertop, are each about 22% of the total.
- Get at least three itemized quotes for the same scope, with plumbing, electrical, permits and drawings listed on separate lines.
Questions to ask before you sign
- How far is the new bathroom from the nearest drain stack, and is that run in the price?
- Will the drain flow by gravity, or does the quote include an ejector pump?
- Who pulls the permit, and does the price include plans and inspections?
- Does the electrical panel have room for the new circuits, a fan and a GFCI outlet?
- What is the allowance for fixtures and tile, and what happens if I pick something dearer?
If you are also upgrading a bathroom you already have, or choosing a shower, see bathroom remodel cost and walk-in shower cost.
Sources
- Fixr, How Much Does It Cost to Add a Bathroom? [2026 Data], updated January 22, 2026.
- This Old House, How Much Does It Cost To Add a Bathroom? (2026 Guide), updated June 12, 2026.
- HomeLight, What’s the Cost to Add a Whole New Bathroom to Your House?, updated July 1, 2026.
- Fixup First, Bathroom Addition Cost 2026, updated May 18, 2026.
- NC Office of the State Fire Marshal, Ceiling Height and Clearances at Bathroom Fixtures (2018 NC Residential Code, R305.1 and R307.1), February 5, 2026.
- Block Renovation, How Much Does It Cost to Add a Bathroom to a House?, updated July 20, 2026.
- Today’s Homeowner, How Much Does an Ejector Pump Cost?, updated April 11, 2025.
- Bob Vila, How Much Does It Cost to Add a Bathroom?, updated February 28, 2023 (older guide).
