What is a Japanese soaking tub, and how big is it?

Q: How big is a Japanese soaking tub?

Retail guides put an ofuro at 42–60 in long, 27–36 in wide and 22–30 in deep. A compact one can be as small as 42 × 28 in on the floor. The footprint is smaller than a 60 × 30 in alcove tub, but the walls are about twice as tall.

Q: How many gallons does a Japanese soaking tub hold?

Our gallons calculator gives 96–123 gallons for ofuro-style shapes with 22–24 in of water, which is 800–1,030 lb of water. A standard tub fills with 30–50 gallons. The exact figure depends on the inside size and where the overflow sits.

Q: Will a Japanese soaking tub fit a small bathroom?

Often yes, because you sit upright and the tub can be 42–48 in long. The outside of a 44 × 34 in oval covers about 10.4 sq ft, against 12.5 sq ft for a 60 × 30 in tub. You still need clear floor in front for stepping in.

Q: How much does a solid stone Japanese soaking tub weigh?

A solid marble ofuro of about 44 × 34 × 28 in weighs about 1,040 lb empty and about 1,800 lb filled with a bather, by our weight model. That is far above a 40 psf residential floor design load, so a structural check comes first.

Last updated November 2026.

Quick answer

Typical size: 42–60 in long, 27–36 in wide, 22–30 in deep (Badeloft ofuro guide)
Posture: Seated upright, water to the shoulders, rather than reclined
Water per fill: 96–123 gal at 22–24 in of water depth (Pietra Fonte gallons calculator)
Hot water needed: About 77% of the fill from the tank at 104°F; Kohler's sheets say 70% or more
Solid stone ofuro: About 44 × 34 × 28 in oval: about 1,040 lb empty marble, about 1,800 lb filled with a bather (our weight model)

A Japanese soaking tub, or ofuro, is a short, deep tub you sit in instead of lie in. Typical sizes run 42–60 in long, 27–36 in wide and 22–30 in deep. At 22–24 in of water it holds about 96–123 gallons, so plan the hot water, the floor and a step in.

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What is a Japanese soaking tub?

An ofuro (the word means bath) is a deep tub for soaking, not for washing. In Japanese practice you rinse first, then sit in clean hot water up to the shoulders. Western tubs are long and shallow and built for lying back. An ofuro is short and tall, usually square, rectangular, round or a rounded oval.

Traditional ones are cedar or hinoki wood. Makers now also build them in acrylic, resin, solid surface and carved stone. Kohler sells a 46 × 46 in acrylic square it describes as echoing Japanese soaking tubs, with a 23-5/8 in depth and a slotted overflow set for deep soaking. This page covers the numbers a buyer needs before ordering one in stone.

Planning a stone bathtub?

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.

How big is a Japanese soaking tub?

Retail guides agree on the range, though makers vary. The footprint is compact and the walls are tall, which is the opposite of a standard American tub.

Measure	Ofuro style	Standard US alcove tub
Length	42–60 in	About 60 in
Width	27–36 in	30–32 in
Height of the walls	22–30 in	14–16 in
Water per fill	60–160 gal	30–50 gal
Posture	Seated, upright	Reclined

Sources: Badeloft ofuro guide; This Old House standard bathtub sizes. Makers differ, so use the spec sheet for any one model.

How do you sit in an ofuro?

You sit upright with knees bent, and the water should reach the shoulders. That is why depth matters more than length. Badeloft describes its stone-resin model as giving true shoulder-deep soaking, and the seated position is what lets a 42–48 in tub work for a full-size adult.

Some designs include a seat or a raised floor on one side. Ask for the seat height, because it sets how much of the water depth you actually use. A seat 12 in off the floor in a tub with 24 in of water leaves 12 in of water over your lap.

How many gallons does a Japanese soaking tub hold?

Depth multiplies everything. Our gallons calculator uses the inside length, width and water depth, with a shape factor of 0.9 for a rectangle and about 0.785 for an oval or round. Four typical ofuro shapes give these totals. Water weighs 8.34 lb per gallon, so a full tub is a real load. For other sizes, run the gallons calculator.

Inside size	Water depth	Shape	Gallons	Water weight	Hot water needed
36 × 36 in	22 in	Round	97	810 lb	About 75 gal
40 × 28 in	22 in	Rectangular	96	800 lb	About 74 gal
44 × 30 in	24 in	Rectangular	123	1,030 lb	About 95 gal
48 × 30 in	24 in	Oval	118	980 lb	About 91 gal

Source: Pietra Fonte gallons calculator. Hot water is 77% of the fill, from the model in the next section.

What water heater does a Japanese soaking tub need?

A big one. With 50°F cold water, a 120°F tank and a 104°F bath, about 77% of the fill has to come from the tank. A 97-gallon soak therefore needs roughly 75 gallons of hot water. Kohler's spec sheets for its bathtubs say the hot water supply should be 70% of the capacity of the bath or greater, which agrees.

Most tank heaters hold 40–50 gallons, so the tank alone will not cover it. First-hour rating is the figure to check. Jaspector's sizing guide gives 78 gallons for a 50-gallon gas unit and 56 for a 50-gallon electric unit, and lists 50–80 gallons of hot water for a soaking tub. Many owners fill in two stages or choose a larger or tankless heater. A licensed plumber should size it.

Will a Japanese soaking tub fit a small bathroom?

Often better than a long tub does. Compare footprints: a stone oval of 44 × 34 in covers about 10.4 sq ft, and a 60 × 30 in oval covers about 12.5 sq ft. The ofuro saves about 2 sq ft and shortens the run along one wall by 16 in.

Height is the catch. A 28 in wall under a sloped ceiling or beside a window sill needs checking, and the rim has to be reachable for cleaning. Keep the clear floor in front of the tub that code and your layout need; see bathroom clearances. For other tight-room ideas, read the small bathroom freestanding tub guide.

How much does a solid stone Japanese soaking tub weigh?

Carved from one block, a marble ofuro of about 44 × 34 × 28 in oval weighs about 1,040 lb empty. Filled to 70% of the basin with a 200 lb bather, our weight model puts it near 1,800 lb. Spread over its 10.4 sq ft footprint, that is about 173 psf, against a 40 psf design live load for non-sleeping rooms in IRC Table R301.5 (30 psf for bedrooms).

Resin ofuro-style tubs listed by Badeloft run 150–300 lb, so stone is a different structural job. Joists, blocking or a slab-on-grade location are for a structural engineer to confirm. The full method is in the stone bathtub weight guide, and every Pietra Fonte quote states the exact dimensions and weight.

How do you get in and out of a deep soaking tub?

You step over a wall 22–30 in tall, then lower yourself onto the seat. Badeloft recommends a step stool and adds that grab bars are advisable. Plan a small step beside the tub, and treat the floor around it as a wet area with a clear path to the door.

Wall height is a specification choice on a made-to-order piece, so say so early. Start from the bespoke page with your bathroom drawing.

Sources

Every piece is made to order. Tell us about the room and we reply within one business day.

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