How to estimate a bathroom remodel trade by trade, line by line
To estimate a bathroom remodel, break the room into its trades (demo, plumbing, electrical, backer board and waterproofing, tile, vanity, drywall, paint), price each one from a counted material list and real hours, add your plumber's and electrician's quotes, then divide the total cost by one minus your target margin. A gutted 5 by 8 hall bath with a new tub, tiled surround, vanity, and toilet runs about $10,760 in cost and prices at $17,350 with a 38 percent margin. The room is only 40 square feet, so a square foot price tells you nothing: the fixture count and the tile layout set the number.
Step by step
- Walk the room and write the scope fixture by fixture. Bathrooms are priced by what gets touched, not by floor area. A 5 by 8 hall bath can hold seven trades inside 40 square feet. List every fixture and mark whether it stays, gets replaced in place, or moves, because a toilet or drain that shifts even two feet is a different plumbing job than a swap.
- Decide what you self-perform and get the sub quotes in hand. Plumbing and electrical usually go to licensed subs, and their numbers are the least predictable part of a bath bid. Send each one the same written scope and photos of the existing rough, and wait for a written quote instead of a number over the phone. On a hall bath you want two firm lines: the plumber's rough and trim, and the electrician's circuit, fan, and lights.
- Price demo, haul-off, and what the tear-out might show. Count demo in crew hours and dump fees. A cast iron tub, a mud-set tile floor, and plaster walls take far longer to remove than a fiberglass unit and drywall, and fourteen hours with one dump run is a fair plan for a gutted 5 by 8. Add a hidden-conditions clause for rot at the tub drain, a cracked closet flange, or old galvanized supply lines, each one a change order if it turns up.
- List fixtures as allowances and rough parts as firm costs. The homeowner picks the tub, toilet, faucet, and trim, so carry them as allowances at supply house cost: about $345 for an alcove tub, $238 for a comfort height toilet, $96 for a lavatory faucet, and $128 for a shower trim kit. The parts they never see are yours to price firm: a shower valve at $148, a tub waste and overflow at $39, angle stops at $9.60, and braided supply lines at $7.60. Print the allowance amounts on the estimate so a $545 wall-hung toilet becomes their upgrade and not your loss.
- Measure the wet area for backer board and waterproofing. A standard tub surround is three walls, about 10 linear feet, and roughly 70 square feet from the tub deck to an 8 foot ceiling. Codes based on the IRC do not accept moisture-resistant drywall as a tile backer in tub and shower areas, so price cement backer board at $1.38 a square foot and a waterproofing membrane at $1.90 over it. If the job has a lined shower pan, the IRC test is 2 inches of water at the threshold held at least 15 minutes with no leak, and local inspectors often ask for longer, so leave a day in the schedule.
- Count tile with waste, then the setting materials. Wall tile is the surround's 70 square feet plus 10 percent waste, so 77 square feet at a $2.40 ceramic allowance. The floor is the room minus the tub footprint, about 28 square feet, but small rooms cut hard around the toilet and the door, so order 32 at $3.90 for porcelain. Then add thinset at $22.50 a bag, grout at $24.50, edge trim at $6.60 a foot, and a niche at $69: on this bath those four come to $291.10 against $309.60 of tile.
- Add the vanity, electrical finish items, drywall, and paint. A 36 inch vanity is three allowance lines: the cabinet at about $332, a quartz top at $59 a square foot for 6 square feet, and an undermount lavatory at $122. Bathroom receptacles need GFCI protection and the NEC calls for a 20 amp circuit to feed them, so the electrician's quote should show a new circuit if the old one is 15 amp or shared with a bedroom or hallway. You supply the $22 GFCI, a $65 exhaust fan (the IRC minimum is 50 cfm on a switch, ducted outdoors), and a vanity light allowance, then close up with moisture-resistant drywall at $0.79 a square foot outside the wet area.
- Total the cost, divide for margin, and send it with exclusions. Add materials, sub quotes, crew hours at a loaded rate, the permit, and disposal to get job cost. Bathrooms generate more punch-list trips and callbacks per dollar than almost any other room, which is why shops that last run them at 35 to 40 percent gross margin, dividing cost by 0.60 to 0.65 instead of adding a percentage on top. List what is out (moving walls, subfloor replacement, mold remediation, fixtures past the allowances) and get the estimate to the homeowner while the walkthrough is still fresh.
The bathroom remodel pricing formula
Job cost equals fixture and finish allowances, plus tile and backer materials, plus drywall and paint, plus the plumber's and electrician's quotes, plus crew hours times your loaded rate, plus permit and disposal. Price equals job cost divided by (1 minus margin). On a $10,757.46 bath, dividing by 0.62 gives $17,350.74 and a true 38 percent margin, while adding 38 percent on top gives $14,845.29, which is only a 27.5 percent margin and $2,505.45 less for the same work.
Take a 5 by 8 hall bath gutted to the studs: cast iron tub out, new alcove tub with a tiled surround, new vanity, toilet, and tile floor. Fixtures and rough parts: alcove tub allowance $345, tub waste and overflow $39, shower valve $148, trim kit allowance $128, comfort height toilet allowance $238, closet flange $8.20, wax ring $4.10, lavatory faucet allowance $96, three angle stops at $9.60 ($28.80), three braided supply lines at $7.60 ($22.80), and a P-trap at $6.60, for $1,064.50. Vanity, all allowances: cabinet $332, 6 square feet of quartz at $59 ($354), and an undermount lavatory at $122, for $808. Tile: 100 square feet of cement backer board at $1.38 ($138), 70 square feet of waterproofing membrane at $1.90 ($133), 77 square feet of ceramic wall tile at a $2.40 allowance ($184.80), 32 square feet of porcelain floor tile at a $3.90 allowance ($124.80), three bags of thinset at $22.50 ($67.50), two bags of grout at $24.50 ($49), a niche at $69, and 16 feet of edge trim at $6.60 ($105.60), for $871.70. Electrical finish: a GFCI receptacle at $22, an exhaust fan at $65, and a vanity light allowance at $65, for $152. Drywall and paint: 160 square feet of moisture-resistant drywall at $0.79 ($126.40), joint compound $18.50, paper tape $8.60, primer on 160 square feet at $0.17 ($27.20), a gallon of paint at $39, and 12 feet of MDF baseboard at $1.38 ($16.56), for $236.26. Materials total $3,132.46. The plumber quotes $1,650 and the electrician $840. Your crew puts in 78 hours at a $60 loaded rate, which is $4,680. Add a $195 permit and $260 in dump fees and job cost is $10,757.46. Divide by 0.62 for a 38 percent margin and the price is $17,350.74, so quote $17,350.
Cost factors bathroom remodelers price for
Moving the drain or the toilet
Fixtures that stay on their existing rough-in are a swap. Moving a toilet means a new 3 inch drain run at $4.45 a foot in PVC plus an open floor, and on a slab it means saw cutting concrete. Price any relocation as its own line with the plumber's number behind it.
What is under the tub and behind the tile
Old tubs hide rotted subfloor, joists notched by a past plumber, and galvanized or cast iron pipe you cannot tie into cleanly. None of it shows at the walkthrough. Name these in the hidden-conditions clause with your hourly rate and how materials get billed, so the fix is a signed change order and not an argument in a torn-up bathroom.
Tile size, pattern, and niches
Tile is an allowance, and the choice moves labor as much as material: large format porcelain at $5.35 a square foot wants a flatter wall and slower setting than basic ceramic at $2.40, and mosaic at $14.75 turns a shower floor into a budget line of its own. Herringbone and diagonal layouts push waste from 10 percent toward 15 or 20. Every niche, bench, and window return adds edge trim at $6.60 a foot and an hour or two of cuts.
Tub replacement versus a tiled shower
A new alcove tub sets in a few hours. Converting to a tiled shower trades it for a foam shower base at $188 or a mud pan with a liner, a drain change, a curb, glass the homeowner still has to choose, and a pan inspection before tile. The IRC also wants at least 900 square inches inside a shower with no dimension under 30 inches, so check that the old tub alcove still clears that after backer and tile.
An occupied house with one bathroom
If this is the only bathroom, the family needs a working toilet most nights, which means resetting it or sequencing the job tighter than you would like. Floor protection from the front door, daily cleanup, and carrying a cast iron tub down a finished staircase all cost hours too. Put those hours in the labor line, and state the expected days without a shower in writing.
Frequently asked questions
How much should I charge for a 5 by 8 bathroom remodel?
Build it from cost, not from a going rate. A full gut with a new tub, tiled surround, vanity, toilet, and tile floor typically carries $3,000 to $3,500 in materials at mid-range allowances, $2,000 to $3,000 in plumbing and electrical subs, and 70 to 90 crew hours. At a 38 percent margin that prices between about $15,500 and $20,000, and nearly all of the spread is fixture and tile choices.
Should I price a bathroom remodel by the square foot?
No. Two 40 square foot bathrooms can sit $8,000 apart because one keeps its fixtures in place and the other moves a toilet and gets a tiled shower with a niche and a bench. Count fixtures, measure the wet walls, and price by line. A per square foot figure is only useful afterward, as a check against your own finished jobs.
Do I need a permit to remodel a bathroom?
Usually yes once you touch plumbing or wiring. New supply or drain piping, a new circuit, or a relocated fixture triggers plumbing and electrical permits in most jurisdictions, while a like-for-like vanity, toilet, or tile swap often does not. Call the building department with the scope before you bid, put the fee in the estimate, and plan for a rough inspection before backer board covers the walls.
What goes behind tile in a tub or shower?
A cement, fiber-cement, or glass mat backer, not green board. The IRC has not allowed moisture-resistant drywall as a tile backer in tub and shower areas for years, and most local codes follow it. Cement backer board runs about $1.38 a square foot and a waterproofing membrane about $1.90, so doing a 70 square foot surround properly costs roughly $230 in materials, which is cheap next to tearing out a failed shower.
Is there software that can write up a bathroom bid for me?
Staxen's estimator, Eddie, turns a spoken or typed walkthrough into a priced line-item estimate. Say the fixtures, the tile square footage, and your sub quotes, review the draft, and text the client a link to e-sign and pay the deposit. Eddie is $59 per month. Josie handles scheduling and change orders approved by text, Ivy handles milestone invoices, and all three together are $149 per month. The first 7 days are free in the app.