Shower Cost Calculator
Put a price on a shower. Enter minutes, showerhead flow in gallons per minute, your water and sewer rate, and whether an electric or gas heater warms the water — and get cost per shower, per month, and per year.
Example: with Shower length (minutes) 15 · Showerhead flow (GPM) 2 · Water heater Electric tank (~95% efficient) · Electricity price ($/kWh) 0.16 · Gas price ($/therm) 1.4 → Cost per shower: $0.94 per shower (30 gal).
- Where it goesWater $0.36 + heating $0.58 (3.6 kWh)
- Per month$28.21 for 30 showers
- Per year$339 per year at that pace
Computed by the calculator below using its default values. Change any input to see your own numbers.
A shower buys two things: the water itself and the energy to heat about 47°F of temperature rise. Heating is usually 60–70% of the total on electric rates.
What a 15-minute shower actually costs
With a standard 2.0 GPM head, a 15-minute shower uses 30 gallons. At a typical combined water-and-sewer rate of $12 per 1,000 gallons, the water is only about 36 cents — heating is the bigger line. Warming 30 gallons by 47°F takes roughly 11,800 BTU: about 3.6 kWh through an electric tank (58 cents at $0.16/kWh) or 0.18 therms through a gas tank (25 cents at $1.40/therm). So the everyday answer is roughly $0.60–$1.00 per long shower, and $340+ a year for a daily electric-heated one.
The levers rank clearly: minutes and flow rate scale the cost linearly, so a 10-minute shower with a 1.8 GPM head cuts the bill by nearly half. Switching electric resistance to a heat-pump water heater cuts the heating term by two-thirds again.
How it’s calculated
Gallons = minutes × GPM. Water cost = gallons × rate ÷ 1,000. Heating energy = gallons × 8.34 lb/gal × 47°F rise (105°F shower mix from ~58°F inlet water; the tank-vs-mix accounting cancels out) = BTU. Electric: BTU ÷ 3,412 ÷ 0.95 efficiency × $/kWh. Gas: BTU ÷ 100,000 ÷ 0.65 efficiency × $/therm. Monthly = per-shower × showers per month; yearly = monthly × 12.
Inlet water temperature and heater efficiency are national-typical (58°F, UEF-style 0.95 electric / 0.65 gas tank) — cold climates, long pipe runs, and old heaters push real costs higher.
Cost per shower at $0.16/kWh, $12 per 1,000 gal (electric tank)
| Shower | Water used | Approx. cost |
|---|---|---|
| 5 min at 2.0 GPM | 10 gal | $0.31 |
| 10 min at 2.0 GPM | 20 gal | $0.63 |
| 15 min at 2.0 GPM | 30 gal | $0.94 |
| 15 min at 2.5 GPM | 37.5 gal | $1.18 |
| 20 min at 2.5 GPM | 50 gal | $1.57 |
Computed with this page's formulas (47°F rise, 95% electric efficiency); rounded to the cent.
Common mistakes
- Counting only the water bill — heating is typically 60–70% of a shower's cost on electric rates.
- Using the water rate alone when your utility bills sewer on the same gallons; combined rates often double the per-gallon price.
- Assuming the showerhead is 2.5 GPM because that is the federal maximum — many modern heads flow 1.8 or less; check the stamp on the face.
- Multiplying by 365 but forgetting household size: four daily showerers make it a four-figure line item on electric heat.
Frequently asked questions
How much does a 15-minute shower cost?
With a 2.0 GPM head, about $0.94 with an electric tank heater ($0.36 water + $0.58 electricity at $0.16/kWh) or about $0.61 with gas at $1.40/therm. Your rates scale it directly.
How many gallons does a shower use?
Minutes × flow rate. Federal rules cap showerheads at 2.5 GPM; common heads run 1.8–2.0. A 15-minute shower at 2.0 GPM is 30 gallons.
What is the formula for shower heating cost?
Gallons × 8.34 × temperature rise gives BTU; divide by 3,412 and the heater efficiency for kWh (electric), or by 100,000 and efficiency for therms (gas), then multiply by your energy price. This page uses a 47°F rise from 58°F inlet to a 105°F shower.
Is a gas or electric water heater cheaper for showers?
At typical US prices gas wins per shower ($0.25 vs $0.58 of heating in the default example) despite lower efficiency, because a therm of gas is much cheaper than its kWh equivalent. Heat-pump electric heaters close most of the gap.
How much do I save with a low-flow showerhead?
Proportionally to flow: going from 2.5 to 1.8 GPM cuts water and heating 28%. For a daily 15-minute electric-heated shower, that is roughly $120 a year.