FREE SIZING TOOL
Bathtub Size Calculator
Find
the Perfect Bathtub Dimensions
Determine ideal bathtub length, width, depth, and water capacity based on bathroom space, user body dimensions, and comfort preferences.
Size & Capacity
Comfort Fit
Space Planning
Calculate Bathtub Size
Enter your bathroom dimensions and body measurements.
Related Tools
How to Use the Bathtub Size Calculator
- Enter Dimensions: Input the available length and width of your bathroom space.
- Enter User Details: Input your height and shoulder width for ergonomic fitting.
- Select Preferences: Choose your preferred bathtub type, occupancy, and depth.
- Choose Units: Select your preferred measurement system (Metric or Imperial).
- Calculate: Click the button to view recommended bathtub dimensions and capacity.
How to Calculate Bathtub Size (Step-by-Step)
1
Bathtub Length
Bathtub Length = User Height × 0.8
2
Bathtub Width
Bathtub Width = Shoulder Width × 1.2
3
Bathtub Depth
Bathtub Depth = User Height × 0.25
4
Water Capacity
Volume (L) = Length × Width × Depth × 0.016
(Usable water ≈ 60–80% of total volume)
(Usable water ≈ 60–80% of total volume)
Real-Life Calculation Scenarios
1
Example: Standard Fit
Measurements
- User Height 175 cm
- Shoulder Width 46 cm
- Space Available 160 × 75 cm
Results
Length (175 × 0.8)
140 cm (choose 160)
Width (46 × 1.2)
55 cm (choose 70-75)
Depth (175 × 0.25)
44 cm
Volume (Usable)
~85 Liters
Rec. Type:
Standard
/ Soaking
2
Example: Tall User & Deep Soak
Measurements
- User Height 188 cm (6'2")
- Shoulder Width 55 cm
- Space Available 180 × 90 cm
Results
Length (188 × 0.8)
151 cm (choose 170-180)
Width (55 × 1.2)
66 cm (choose 80+)
Depth (188 × 0.25)
47 cm (Deep Soak)
Volume (Est.)
~220 Liters
Rec. Type:
Freestanding
/ Large
Standard Bathtub Sizes
| Bathtub Type | Length (cm) | Width (cm) | Depth (cm) | Ideal For |
|---|---|---|---|---|
| Small / Compact | 120–137 | 70–76 | 35–40 | Small bathrooms |
| Standard | 152 | 76–81 | 35–50 | Average bathrooms |
| Large / Soaking | 168–183 | 81–91 | 45–60 | Master bathrooms |
| Corner Tub | 120–150 | 120–150 | 45–60 | Corner spaces |
| Freestanding | 152–183 | 76–91 | 45–60 | Luxury layouts |
| Whirlpool | 152–183 | 81–91 | 50–60 | Spa experience |
Bathtub Size by User Height
| User Height (cm) | Length (cm) | Depth (cm) | Capacity (L) | Tub Type |
|---|---|---|---|---|
| 150 | 120 | 38 | 120–150 | Compact |
| 160 | 130 | 40 | 150–180 | Standard |
| 170 | 136 | 43 | 180–220 | Standard |
| 180 | 145 | 45 | 220–260 | Large |
| 190 | 152 | 48 | 260–300 | Soaking |
Bathtub Design & Space Tips
Space & Support
- Clearance ZonesLeave at least 12 in (30 cm) clearance around freestanding tubs for cleaning and access.
- Structural IntegrityReinforce floor joists if necessary. A full soak tub can weigh over 300kg (660 lbs).
Comfort & Layout
- Ergonomic SlopeLook for a backrest angle of at least 15-20 degrees for maximum reclining comfort.
- Visual BalanceIn small bathrooms, a corner or alcove tub maximizes floor space compared to freestanding.
Bathtub Maintenance Tips
- Weekly Cleaning: Clean weekly with non-abrasive cleaners to preserve the finish.
- Acrylic Care: Avoid bleach on acrylic tubs as it can cause discoloration.
- Rinsing: Rinse thoroughly after use to prevent soap and residue buildup.
- Yearly Check: Inspect drains and overflow seals yearly to prevent leaks.
Conversion Formulas
Length
cm = inches × 2.54
inches = cm ÷ 2.54
Volume
gal = L ÷ 3.785
L = gal × 3.785
Bathtub Size Calculator FAQs
What size bathtub is best for my bathroom?
The best size depends on your available space and layout. Standard tubs are 60 in (152 cm) long.
Measure your alcove or wall space carefully and leave at least 30 cm clearance for freestanding
models.
How deep should a soaking tub be?
A soaking tub should be deep enough to cover your shoulders comfortably. Look for a water depth
of at least 14–15 inches (35–38 cm) to the overflow, which typically means a total tub depth of
20 inches (50 cm) or more.
How much water does a bathtub hold?
A standard bathtub holds about 150–180 liters (40–50 gallons). Deep soaking or large corner tubs
can hold significantly more, often exceeding 250 liters (65 gallons).
Can two people fit in one bathtub?
Yes, but you'll need a larger tub. Look for "two-person" tubs which are typically wider (at
least 42 inches or 105 cm) and have a center drain configuration so neither person sits on the
drain.
How much clearance is required around a tub?
For freestanding tubs, aim for at least 4 inches (10 cm) between the tub ends and walls, and
ideally 12 inches (30 cm) or more for ease of cleaning and access.
More Home Calculators
Scrub Brush Size Calculator
Select the ideal scrub brush size for focused cleaning power.
Calculate Brush SizeShower Curtain Size Calculator
Calculate the correct shower curtain dimensions for your tub.
Calculate Curtain Size