★ COST COMPARISON · EVERYDAY · WATER & ENERGY
A shower wins by $208.94 a year at the defaults — but only because it uses 20 gallons against a bath's 36. A 10-minute shower at 2.0 gallons per minute costs $0.72 per use and $261.17 a year at one bath-or-shower per day. A 36-gallon bath costs $1.29 per use and $470.11 a year. The water is the smaller half of both bills — heating it is the larger half. Enter your own shower length, flow, rates, and temperatures below to see your own gap.
A bath feels like the luxury and a shower feels like the saving, but both bills are just gallons times two rates: what the water costs, and what heating it costs. A long, high-flow shower can easily pass a modest bath, and a shallow bath can beat a marathon shower. Pricing both with the same water rate, the same electricity rate, and the same temperatures settles it for your bathroom, not for the average one.
Shower gallons = shower minutes × flow in gallons per minute. Bath gallons = the tub-fill gallons you enter (default 36, about 70% of a standard 50-gallon tub — stated as an assumption, not a measured average). Heating energy in kWh = gallons × 8.34 lb per gallon × temperature rise in °F ÷ 3412 BTU per kWh. Water cost = gallons × water-plus-sewer rate per gallon. Energy cost = kWh × electricity rate per kWh. Per-use total = water cost + energy cost. Annual total = per-use total × bathing days per year (default 365: one bath-or-shower per day). The annual saving = bath annual total − shower annual total; a negative saving means bathing wins. The model prices water heating at the electricity rate you enter; if your water heater runs on gas, enter your gas cost converted to a per-kWh-equivalent rate, or read the energy figure in kWh and price it yourself. It does not count the water heater's standby losses, which fall on both sides.
Setup: 10 minutes, 2.0 gpm, 36-gallon bath, $0.015/gal water-plus-sewer, $0.17/kWh, 55°F cold, 105°F hot (a 50°F rise), 365 days.
Line 1 — shower gallons. 10 × 2.0 = 20 gallons.
Line 2 — heating energy. 20 × 8.34 × 50 ÷ 3412 = 2.44 kWh for the shower; 36 × 8.34 × 50 ÷ 3412 = 4.40 kWh for the bath.
Line 3 — water cost. 20 × $0.015 = $0.30 per shower; 36 × $0.015 = $0.54 per bath.
Line 4 — energy cost. 2.44 × $0.17 = $0.42 per shower; 4.40 × $0.17 = $0.75 per bath.
Line 5 — per-use totals. $0.30 + $0.42 = $0.72 per shower; $0.54 + $0.75 = $1.29 per bath.
Line 6 — annual totals. $0.72 × 365 = $261.17 a year showering; $1.29 × 365 = $470.11 a year bathing (annual figures are computed from unrounded per-use totals, then rounded).
Line 7 — the saving. $470.11 − $261.17 = $208.94 a year by showering.
Short shower: 5 minutes. Shower gallons fall to 10, heating energy to 1.22 kWh, the per-use cost to $0.36, and the annual shower cost to $130.58 — so a 5-minute shower against a daily bath saves $339.52 a year.
High-flow showerhead: 2.5 gpm. A 10-minute shower uses 25 gallons and 3.06 kWh, costs $0.89 per use and $326.46 a year, so the gap against a daily bath narrows to $143.64 a year.
Expensive electricity: $0.25 per kWh. The shower costs $0.91 per use and $332.54 a year; the bath costs $1.64 per use and $598.58 a year; the yearly gap widens to $266.03, because heating dominates both bills.
Deep bath: 42 gallons. The bath uses 5.13 kWh, costs $1.50 per use and $548.46 a year, so the gap against the default shower widens to $287.29 a year.
| Output | Formula | What it means |
|---|---|---|
| Shower gallons | Minutes × gallons per minute | 20 at the defaults — the water one shower uses. |
| Bath gallons | Tub-fill gallons entered | 36 at the defaults — about 70% of a standard 50-gallon tub. |
| Heating energy | Gallons × 8.34 × temp rise ÷ 3412 | 2.44 kWh shower, 4.40 kWh bath — the heat each bath-or-shower needs. |
| Water cost | Gallons × water + sewer $/gal | $0.30 shower, $0.54 bath — the smaller half of each bill. |
| Energy cost | kWh × electricity $/kWh | $0.42 shower, $0.75 bath — the larger half of each bill. |
| Per-use total | Water cost + energy cost | $0.72 shower, $1.29 bath. |
| Annual total | Per-use total × days per year | $261.17 shower, $470.11 bath at 365 days. |
| Annual saving | Bath annual − shower annual | $208.94 at the defaults — positive means showering wins. |
The comparison is exact for the numbers you enter, but several inputs are stated assumptions, not measurements. The 36-gallon default assumes a tub filled to about 70% of a standard 50-gallon tub; your tub and your fill level set the real figure, so measure it once if the bath side matters to you. The model heats every gallon from the cold-water temperature to the bathing temperature, which slightly overstates a shower's heating cost, since shower water is mixed with cold water at the tap rather than heated in full — the error is small and falls on the shower side, so the shower's advantage is, if anything, understated. It prices heating at your electricity rate; gas water heaters need a converted rate, and tank standby losses are not counted on either side. It does not count shampoo, soap, or the water heater's purchase cost. Error policy: missing, non-numeric, or out-of-range inputs are reported as errors rather than calculated, and a hot-water temperature at or below the cold-water temperature is an error.
Bright Side Kit. "Shower vs Bath Cost Calculator 2026." https://brightoolbox.com/shower-vs-bath/ Accessed October 24, 2026.Yes at the defaults: $0.72 per shower against $1.29 per bath, or $261.17 against $470.11 a year at one bath-or-shower per day. The shower uses 20 gallons against the bath's 36, and heating is the larger half of both bills.
$0.72 per shower: $0.30 of water plus $0.42 of heating, at 2.0 gallons per minute, $0.015 per gallon, $0.17 per kWh, and a 50-degree temperature rise. At one shower a day that is $261.17 a year.
$1.29 per bath at the defaults: $0.54 of water plus $0.75 of heating for 36 gallons. At one bath a day that is $470.11 a year. A deeper 42-gallon bath costs $1.50 per use and $548.46 a year.
Yes — a long, high-flow shower passes a shallow bath. A 20-minute shower at 2.5 gpm uses 50 gallons, more than the default 36-gallon bath, and costs more per use. Enter your own minutes and flow to find your crossover.
Because raising water 50 degrees takes real energy: 2.44 kWh for a 20-gallon shower, 4.40 kWh for a 36-gallon bath. At $0.17 per kWh that is $0.42 and $0.75, against $0.30 and $0.54 of water. Higher electricity rates widen heating's lead further.
Enter your gas cost converted to a per-kWh-equivalent rate, or read the kWh figure and price it yourself. The calculator reports heating energy in kWh either way, so a gas household can multiply 2.44 kWh (shower) or 4.40 kWh (bath) by its own converted rate.
Yes, roughly in proportion to the flow cut. Dropping from 2.0 to 1.5 gpm cuts a 10-minute shower from 20 to 15 gallons, cutting both the water and the heating cost by a quarter. The saving is larger where electricity is expensive.
It depends on your tub and fill level — the 36-gallon default is an assumption, about 70% of a standard 50-gallon tub. A shallow soak uses less, a full tub to the overflow uses more. If the bath side matters to you, measure your tub once: fill it to your usual level and read your water meter, or estimate from the tub's dimensions.