Owners call with a box in the garage: “I already bought one on Amazon. Can you just install it for $995?” That sounds like free margin because the tub invoice left the bid. It did not leave the trip, the set hours, or the chance that the drain does not line up with their alcove.
Open the free walk-in tub bid calculatorA contractor-supplied acrylic soaker still carries the unit invoice. An owner-supplied tub that actually fits zeros that line and keeps the same set hours. On a typical cheap special — $42 wage, 30% burden, 15% overhead, 20% target margin, eight miles — the contractor-supplied bid is about $3,757. Zeroing a $1,850 soaker drops it to about $1,098, and the owner-supplied walk-away is about $878. Taking the Amazon special to “just install what they bought” at $995 keeps about $117 when the drain lines up. A drain that does not match still loses about $362.
| You supply | They supply, it fits | They supply, wrong drain | |
|---|---|---|---|
| Tub invoice in the bid | Yes | No | No |
| Set hours | Same | Same | Same, plus an inspect trip |
| Walk-away on the cheap special | About $3,006 | About $878 | About $1,357 |
| At $995 install-only | Loses about $2,011 | Keeps about $117 | Loses about $362 |
The $995 Amazon special is usually a cheap soaker. The job people actually buy is a whirlpool with grab bars: they paid $4,200 at a showroom and want you to “just set it for $1,499.” Same calculator, same owner-supplied rows. On the typical aging-in-place alcove — whirlpool, outward door, grab bars, handheld, permit, 14 miles — owner-supplied walk-away is $2,082.34. $1,499 still loses $583.34 even when the unit fits. A wrong drain walks away at $2,561.39.
| Path | Hours | Your bid | Walk-away | At $1,499 |
|---|---|---|---|---|
| You supply the whirlpool | 18.8 h | $8,640.43 | $6,912.34 | loses $5,413.34 |
| Owner supplies — it fits | 18.8 h | $2,602.93 | $2,082.34 | loses $583.34 |
| Owner supplies — wrong drain | 22.4 h | $3,201.74 | $2,561.39 | loses $1,062.39 |
So $995 can cover a soaker that fits, and $1,499 still loses on the whirlpool they actually bought. Load the typical aging-in-place preset and put their number in “price you’re considering.” None of those sentences is advice to take or refuse the crate.
Amazon listings skip the template. Drains come in on the wrong end, overflow kits are missing, and the door seal they expect you to eat is not in the box. Setting the wrong unit means a second dispatch plus hardware. Price that callback on the same alcove before you agree. The calculator adds a starting inspect trip and a missing-kit line on top of the rates you already typed.
Open the walk-in tub bid calculator, enter the bath you are standing in, and put their install-only number in “price you’re considering.” The who-supplies table scores that number against you-supply, owner-supplies-it-fits, and owner-supplies-wrong-drain. Nothing is uploaded.
This is the same arithmetic as how much to charge to install a walk-in tub. They want Saturday after a fall? See should I take a Saturday walk-in tub call. It is not a building-code determination, an accessibility approval, a plumbing design, or a reason to refuse a customer — it is the walk-away number on each supply path.
Only after you price the set without the tub invoice. Setting their unit is still a trip and crew hours. A $995 install-only special often covers that walk-away when the drain lines up, and loses money when the overflow kit is missing or the drain does not match.
Only if the unit actually fits. Zeroing a $1,850 soaker invoice drops the bid, but loaded labor, door hardware, travel, and overhead stay. On a typical alcove swap the owner-supplied walk-away is about $878, so $995 keeps a thin margin. A drain that does not line up or a missing overflow kit adds a second trip and walks away about $1,357.
That is a different job than the $995 soaker special. On a typical aging-in-place alcove — whirlpool, outward door, grab bars, handheld, permit — the owner-supplied walk-away is $2,082.34. $1,499 still loses $583.34 even when the unit fits. A wrong drain walks away at $2,561.39.
That is a second dispatch plus a drain kit or overflow they did not have. Price that callback on the same bath before you agree to install whatever they rolled into the garage. The calculator adds a starting inspect trip and missing-kit dollars on top of your current rates.