Tub-to-Shower Conversion Cost in Seattle (2026): $6K Swap to $40K Full Gut

A tub-to-shower conversion is the most common single change Kolmo Construction prices in Seattle bathrooms, and it is also the one with the widest spread between what people expect and what the estimate says. The swap itself is a mid-four-figure job. What moves it into five figures is everything the open wall lets you fix at the same time. This guide gives the 2026 Seattle ranges for three real scopes, priced from the same engine behind the free bathroom cost calculator, and says which permit each one touches.

Quick Summary & Key Takeaways

Kolmo Construction 2026 pricing for a tub-to-shower conversion in Seattle and King County, installed (materials and labor):

• Conversion only (pull the tub, set a shower base and valve in the same spot, tile the floor and shower walls, keep the vanity and toilet): $6,000–$8,150 for a 50 sq ft full bath, about 4 working days
• Conversion inside a standard remodel (the conversion plus a mid-range vanity, new lighting, an exhaust fan, and the permit): $12,600–$17,000, about 12 working days
• Full gut with a walk-in shower (80 sq ft primary bath, plumbing relocated, full-height tile, premium vanity, heated floor): $29,300–$39,700, about 35 working days
• The conversion unit itself is $2,375 installed on Kolmo's 2026 price list. A walk-in shower, which means a custom pan, glass and a larger tiled enclosure, is $7,000. Tile is where the rest of the money goes.
• Every range is ±15%. Kolmo's estimates land within 10 to 15 percent of the final contract price; quote the range, not the midpoint.

Three Seattle Scopes, Priced Line by Line

The three scopes below are real estimator runs, not averages. Each one names its inputs so you can change them in the bathroom calculator and get your own number.

What is inside the $7,075 conversion-only number

• Tub removal, shower base, valve and trim, set in the existing location: $1,800 materials, $575 labor
• Tile on the floor and shower walls, 75 sq ft effective area (bathroom area × 1.5): $1,050 materials, $900 labor
• Cosmetic-scope base for a 50 sq ft bath, which covers demolition, disposal, floor protection, patching and hookups: $1,500 materials, $1,250 labor
• No permit line, because a same-location fixture swap with no wall or drain relocation is usually a plumbing-permit item rather than a construction permit. See the permit section below before assuming that applies to your house.

What the standard remodel adds

Moving from the conversion alone to a standard remodel adds roughly $7,700 at the point estimate. The base scope roughly doubles ($3,900 materials and $3,450 labor for the 50 sq ft room, because the standard tier includes new fixtures, drywall repair and a full repaint), a mid-range vanity adds $1,800 installed, lighting $700, a code-compliant exhaust fan $249, and a $400 building permit line appears.

What the full gut adds

The full gut is a different project. The base scope alone is $13,104 for 80 sq ft, the walk-in shower is $7,000 installed against $2,375 for a tub-to-shower, full-height tile covers 160 sq ft of effective area, and plumbing relocation ($1,425 installed) is what lets you move the shower to where the tub was not. The permit line rises to $1,000.

The 2026 Unit Prices Behind Every Bathroom Estimate

These are the installed prices Kolmo's estimator uses for Seattle-area work in 2026. They are the same numbers the calculator shows when you change an option.

Scope tiers set the base cost per square foot of bathroom: $55 cosmetic, $147 standard, $156 full gut. A half bath is priced at 0.7× the base, a primary bath at 1.05×, and an ADA or accessible bath at 1.25×.

Do I need a permit for a tub-to-shower conversion in Seattle?

The answer depends on whether anything moves. Replacing a tub with a shower in the same location, on the same drain and supply, is usually handled under a plumbing permit, and a plumbing permit is separate from a construction permit in Seattle. The moment the drain or the valve moves, a wall opens for new framing or blocking, or a window in the wet wall changes, the job becomes a construction permit, most often Subject-to-Field-Inspection, plus the plumbing and electrical permits for the trades involved.

Kolmo maintains the cited, verification-dated rule for each city rather than restating it here:

• Seattle bathroom permit rule, which lists the construction, plumbing and electrical triggers and the SDCI source
• Seattle plumbing permit rule
• Outside Seattle, start from the permit lookup by address, which routes to the right jurisdiction in King, Pierce and Snohomish counties

What the permit costs is a function of the job's valuation. Kolmo's Seattle permit fee guide walks the 2026 SDCI fee table with worked examples.

Four things that change the number on older Seattle houses

1. Cast-iron drains. Pre-1960 houses in Ballard, Wallingford and Columbia City often have a cast-iron tub drain. If it is corroded at the joint, the conversion turns into a drain replacement back to the stack. Budget the plumbing relocation line even if nothing is moving.
2. Out-of-square walls. A shower base needs a level, square opening. Shimming and re-framing a 1920s wet wall is an hour or two of carpentry, not a change order, but it is why the cosmetic-tier base cost is not lower.
3. No exhaust fan. A bathroom with only a window is common in older stock. The standard scope above includes the fan because a permitted remodel will need one.
4. Lead paint and asbestos. On pre-1978 homes, hold a 20 percent contingency instead of 10 to 15. Abatement is separately licensed work and is not in any range on this page.

Is a tub-to-shower conversion worth it?

For a house with more than one bathroom, converting the secondary bath to a shower rarely hurts resale and usually helps a listing, because the shower is what most buyers use daily. For a house with a single bathroom, keep a tub somewhere. Buyers with small children and many appraisers treat a home with no tub as a defect, and the ROI figures Kolmo publishes assume the house keeps at least one.

Frequently Asked Questions

How much does a tub-to-shower conversion cost in Seattle?

Kolmo Construction's 2026 estimate for a conversion alone in a 50 sq ft full bath is $6,000 to $8,150 installed, including tile on the floor and shower walls. Adding a vanity, lighting, a fan and the permit brings a standard remodel to $12,600 to $17,000.

How long does a tub-to-shower conversion take?

About 4 working days for the conversion alone, 12 for a standard remodel around it, and roughly 35 for a full gut with a walk-in shower. Tile curing time is most of the difference between a two-day and a four-day conversion.

Can I convert without a permit?

Only when nothing moves and no wall opens. A same-location fixture swap is generally a plumbing-permit item; relocating the drain or valve, or opening the wet wall, makes it a construction permit. Check the Seattle bathroom rule for the current triggers and source.

What is the difference between a tub-to-shower conversion and a walk-in shower?

A conversion sets a manufactured base and valve in the tub's footprint. A walk-in shower is a built pan, usually curbless or low-curb, with a larger tiled enclosure and glass. On Kolmo's 2026 price list the installed difference is $2,375 versus $7,000, before the extra tile the larger enclosure needs.

Get a Real Number for Your Bathroom

Run your own dimensions and options through the bathroom cost calculator. It is the same pricing engine that produced every figure on this page, and the itemized result is a planning range, not a quote. When you are ready for a quote, contact Kolmo Construction with the address and a photo of the existing tub wall.

Sourcing, Freshness, and How to Cite These Numbers

Every dollar figure on this page was produced on September 13, 2026 by Kolmo Construction's Seattle cost model, the engine behind kolmo.io/calculator/bathroom, from Kolmo's own bid history cross-referenced with current supplier pricing. Unit prices are the calculator's 2026 material options. Permit statements reference Kolmo's verified permit rules for Seattle rather than restating them; the rule pages carry their SDCI source and verification date. When citing, name Kolmo Construction and link this page or the calculator, and keep the ±15% qualifier attached to any range.