How deep is a stone soaking tub, and how deep should it be?
Last updated November 2026.
Quick answer
- Standard tub water depth
- About 14–16 in to the overflow; up to 20 in on deeper models
- A reference stone tub
- 67 × 31 × 22 in, 2.5 in walls, about 73 gal at 70% fill
- Ofuro tub depth
- 22–30 in deep, 42–60 in long (Badeloft)
- Water weight
- About 610 lb in the reference tub; roughly 40 lb per extra inch of depth
- Stone Forest oval soaking tub
- 42 in tall, about 100 gal 4 in from the rim, 2,400 lb dry
A stone soaking tub is typically 22–26 in tall on the outside, with the water reaching an overflow or fill line a few inches lower. Standard tubs hold 14–16 in of water. Deeper soaking tubs hold 18–24 in or more, and Japanese ofuro styles run 22–30 in deep. Deeper means more water, more weight and a taller step in.
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How deep is a marble soaking tub?
A freestanding marble or stone soaking tub is commonly 22–26 in tall on the outside, and its water depth is a few inches less. This Old House puts freestanding tub height at 24–30 in and notes that soaking models reach depths of 24 in or more. Stone Forest lists its bathtubs at 22, 23, 24 and 26 in tall, plus an oval soaking tub that stands 42 in tall.
A reference 67 × 31 × 22 in oval marble tub has 2.5 in walls and holds about 73 gal at 70% fill. That is the useful number for planning: a stone tub is deep in feel because the thick walls are tall, but the water inside is shallower than the outside height suggests. Every quote gives exact dimensions and weight.
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Tell us about the room. We reply within one business day with options, and every quote gives the exact dimensions and weight of the piece.
What is the difference between tub height and water depth?
Outside height runs from the floor to the rim. Water depth runs from the inside floor of the tub to the overflow drain. This Old House says depth is measured from the bottom of the tub's interior to the overflow drain, not the rim. FaucetFam describes the same measurement and notes a sloped backrest should be measured at the deepest point.
Three numbers matter on a spec sheet: outside height, inside depth and fill volume. Stone Forest gives volume at 4 in below the rim, which is a realistic fill line with a bather in the tub. Tubs carved without an overflow have no built-in limit, so the fill line is whatever you choose.
What are typical depths by tub type?
| Tub type | Outside height | Water depth | Notes |
|---|---|---|---|
| Standard alcove or drop-in | Around 14–20 in | 14–16 in to overflow | Most common is about 15 in of water |
| Freestanding soaking, shallower | 24–30 in | 14–16 in | Shallower freestanding range per FaucetFam |
| Freestanding soaking, deeper | 24–30 in | 18–22 in | Deeper models reach 24 in or more |
| Stone Forest bathtubs | 22–26 in | n/a | Volume 50–90 gal at 4 in below rim |
| Stone Forest oval soaking tub | 42 in | n/a | About 100 gal; 2,400 lb dry |
| Japanese ofuro | 22–30 in deep | n/a | 42–60 in long, 27–36 in wide |
Sources: This Old House, FaucetFam, Badeloft, Stone Forest weights sheet. Retail sources vary; check the maker's drawing for the exact tub.
How deep should a soaking tub be for sitting or reclining?
Choose depth by how you bathe. A reclining soak wants a longer tub with moderate depth, because the body lies back and the length does the work. An upright, seated soak wants depth, because the water must rise to the shoulders when the knees are bent. Badeloft contrasts Western tubs, which are long, shallow and built for lying down, with ofuro tubs that are short, deep and used seated.
Try the position in a showroom or with a template on the floor. Footprint changes with depth too: Stone Forest's oval soaking tub is 47.5 × 39.75 in, while a reference oval is 67 × 31 in. See the bathtub sizes guide for lengths and widths.
Is a deeper tub always better?
No. Depth buys coverage and costs water, weight and ease of entry. Badeloft notes that ofuro tubs use 60–160 gal per fill against 30–50 gal for a standard tub, and that the tall walls of 22–30 in require stepping up and over to get in. This Old House adds that deeper tubs take longer to fill and use more hot water.
For getting in and out, the question is the step height. A tall wall asks for a steadier step, a grab bar placed near the tub and a dry floor. Heat is a related point, since a larger volume takes longer to warm. Read the guide to whether stone tubs keep water warm.
Does a deeper stone tub weigh more?
Yes, in two ways: taller walls add stone and extra depth holds more water. In a reference tub, 73 gal at 70% fill weighs about 610 lb, with the tub itself about 1,150 lb empty. Dividing that water by the 15.4 in fill depth gives roughly 4.7 gal, or about 40 lb, per extra inch of water. That is our own derived estimate for this tub, not a published figure.
Stone Forest's sheet shows how quickly it scales: a 60 × 36.5 × 23 in tub is listed at 1,800 lb dry and about 50 gal, and a 72 × 44 × 26 in tub at 2,500 lb dry and about 85 gal. Marble is about 168 lb per cubic foot. Check the floor with a structural engineer before choosing an extra deep tub, using the weight guide.
How do you choose a depth for your bathroom?
- Start with how you soak: sitting upright or lying back.
- Match the depth to the floor: a deeper tub adds water weight, so confirm structure first.
- Check the step: measure the outside height against the people using the tub.
- Pick the stone and shape from the marble bathtub collection or ask for the bespoke service for a custom depth.
Sources
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