Bathtub Size Calculator
Pick a tub type and size to get its usable water in litres, the hot water & geyser load to reach your bath temperature, the heating cost, the fill time, and whether the tub plus access clearance fits your bathroom. Indicative India 2026 — confirm dimensions and tariffs locally.
Your tub & bathroom
Bathroom size (mm)
Geometric box to the overflow is 408 L; usable water is ~62% of that once the tub's taper and a bather's displacement are removed. Fit needs about 1,700 × 1,500 mm of clear floor (rectangular tub set against one long wall.). All figures indicative — confirm locally.
Usable water in this tub
0 litres
about 0 L hot + 153 L cold to reach a 40°C bath
Hot water needed
100 L
39% of fill · 60°C geyser
Heating energy
3.8 kWh
≈ ₹31 at ₹8/unit
Fill time
21 min
at 12 L/min
Room fit
Fits
300 mm to spare
Hot vs cold split for this bath, against a typical 8-minute shower (72 L). A tub bath uses ~3.5× a shower's water. Indicative — confirm locally.
Plan the tub, geyser & layout
Get tub, hot-water and waterproofing guidance for this bathroom from DesignAI.
Estimates are indicative. Usable litres depend on the exact tub shape, overflow height and how deep you actually fill; a full tub bath typically uses several times the water and heating of a short shower, so factor running costs into the choice. Confirm interior dimensions, geyser capacity, water pressure and your electricity tariff before you order or install.
Frequently asked questions
- How does the bathtub size calculator work?
- It multiplies your tub's interior length, width and water depth to get the geometric box up to the overflow, then keeps only the usable fraction (roughly 55 to 65 percent for most tubs) once the tub's taper and a bather's displacement are removed. From that usable litres it works out the hot water needed to reach your bath temperature, the geyser energy and rupee cost, the fill time and whether the tub plus access clearance fits your bathroom.
- What inputs and default values should I use?
- Pick a tub type to auto-fill typical interior dimensions, or enter your own length, width and water depth in mm from the product sheet. Set bath temperature around 40°C, cold inlet near 27°C, geyser at 55 to 60°C, a fill flow of about 12 litres per minute and your electricity tariff in rupees per unit. Add your bathroom length and width in mm for the room-fit check. Change any value to match your actual tub and supply.
- How much water and hot water does a bathtub use compared with a shower?
- A standard 1700 mm soaking tub holds roughly 250 to 320 usable litres, so a full tub bath uses several times the water of a typical 8-minute shower at about 72 litres. Only the portion needed to lift the water to bath temperature is heated, so hot demand and running cost rise with tub size and colder inlet water. Treat the litres and cost as indicative for planning and confirm your geyser capacity and tariff before deciding.
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