How much does a stone bathtub weigh?
Last updated October 2026.
Quick answer
- Empty, solid stone
- 1,100–2,500 lb (500–1,130 kg)
- Water when filled
- 500–900 lb (230–410 kg)
- Typical 67″ marble tub, filled
- about 2,000 lb (900 kg)
- Load on its footprint
- about 170 lb per sq ft, vs 40 psf typical floor design
- Cast iron, for comparison
- 250–500 lb (110–230 kg)
- Before you order
- Have a structural engineer check an upper floor
A solid natural-stone bathtub weighs about 1,100 to 2,500 lb (500 to 1,130 kg) empty, depending on size, wall thickness and stone. Filled, add roughly 500 to 900 lb (230 to 410 kg) of water plus the bather: a typical 67-inch marble tub comes to about 2,000 lb (900 kg), so check the floor before you order.
Stone bathtub weight calculator
- Empty tub
- 1,150 lb
- 520 kg
- Water
- 610 lb
- 73 gallons, 280 kg
- Filled, with bather
- 1,960 lb
- 890 kg
- Load on its footprint
- 173 psf
- vs 40 psf typical floor design load
An estimate from typical stone density and your dimensions. Use the maker's published weight for the actual piece, and have a structural engineer check the floor.
How much does a bathtub weigh by material?
| Material | Typical empty weight | kg | Notes |
|---|---|---|---|
| Acrylic | 60–120 lb | 27–54 kg | Light enough for two people to carry. |
| Enameled steel | 60–150 lb | 27–68 kg | Thin pressed steel; common in alcove tubs. |
| Cast iron | 250–500 lb | 110–230 kg | Clawfoot and alcove tubs; a 5-foot clawfoot is usually 300 lb or more. |
| Stone resin (solid surface) | 200–500 lb | 90–230 kg | Crushed stone bound with resin, cast in a mold. |
| Solid natural stone | 1,100–2,500 lb | 500–1,130 kg | Carved from one block; see published examples below. |
Typical ranges for freestanding and alcove tubs of 55–72 inches. Always use the spec sheet for the model you are buying.
What do real stone tubs weigh?
- Stone Forest Calma 66″ marble tub: 1,800 lb
- Stone Forest Bateau 78″ honey onyx tub: 2,000 lb
- Waterworks Ibla 67″ marble tub: 1,122 lb
- Cultheir 72″ marble tub, filled: 2,500 lb
How much does a cast iron bathtub weigh?
Most cast iron bathtubs weigh about 250 to 500 lb empty; a 5-foot clawfoot is usually 300 lb or more. A solid stone tub of the same length typically weighs three to five times as much, before water.
How much does a filled stone bathtub weigh?
Water weighs 8.34 lb per US gallon. A freestanding soaking tub holds roughly 50 to 110 gallons at a comfortable fill, so the water alone adds about 400 to 900 lb. Add the stone and a bather and a filled stone tub typically totals about 1,750 to 3,600 lb (790 to 1,630 kg).
Can my floor hold a marble bathtub?
Often, but check first. Most US homes design floors for a live load of 40 lb per square foot, while a filled stone tub can put well over 150 lb per square foot on its footprint. On a slab-on-grade floor that is rarely an issue; on an upper floor, a structural engineer should check the joists and may add blocking, a doubled joist or a beam.
Worked example: a 67 × 31 × 22 inch oval marble tub with 2.5-inch walls weighs about 1,150 lb empty. Filled to 70% it holds about 73 gallons (610 lb), and with a 200 lb bather the total is about 1,960 lb on roughly 11.5 square feet: around 173 lb per square foot.
What reinforcement does a floor need for a stone bathtub?
On a concrete slab at ground level, usually none. On a wood-framed upper floor, an engineer may call for blocking between joists, sistered or doubled joists under the tub, or a beam or posts below, depending on joist size, span and where the tub sits. Placing the tub near a bearing wall reduces what is needed.
What a structural engineer usually looks at:
- Joist size, spacing, span and direction relative to the tub.
- Whether the tub sits mid-span or near a bearing wall (near a wall is far better).
- Adding blocking, sistering or doubling joists, or a beam below, if needed.
- The finished floor: stone tile and mortar bed add their own weight.
How do you get a stone tub into the room?
A stone tub cannot flex or be tipped through a tight turn like acrylic. Measure every door, hallway, stair and landing on the delivery path, and allow for the crate and a pallet jack or stair climber. Tell your delivery team about steps and floors in advance; white-glove crews plan the route before the day.
How heavy are Pietra Fonte tubs?
Every Pietra Fonte tub is carved to order, and we give you its exact weight and dimensions with the quote so your contractor and engineer can check the floor before production starts. See our stone bathtubs, bathtub sizes and the marble bathtub cost guide.