Everyday Money
Cost Per Shower Calculator
Combine shower length, flow rate, water price and heating electricity into a per-shower cost.
How much does a shower cost?
Most of the cost of a shower is heating the water, not the water itself. Flow rate and minutes matter more than people usually expect — a long high-flow shower can cost more per week than a small appliance left on standby. Enter your tariff, flow and duration for a rule-of-thumb cost per shower and a monthly total. Boilers, heat pumps and electric showers differ in efficiency; treat the result as an estimate and validate with a smart meter if you have one. Low-flow heads often save more than rushing. Compare appliance habits with appliance running cost and wider energy thinking with cost per use. Not an energy-supplier quote or plumbing survey. Households on water meters still usually find heat dominates, but long power showers in hard-water areas also shorten element life — another soft cost outside this model. Teenagers timing showers against a playlist can cut minutes without a lecture about tariffs. If you install a thermostatic mixer, re-measure flow; the old litres-per-minute figure may no longer apply.
Worked example
A 9 L/min shower for 8 minutes uses about 72 litres. Heating that water might take roughly 3–4 kWh depending on inlet temperature and system efficiency. At 28p/kWh, one shower can sit around £0.85–£1.10 before water charges. Cutting to 5 minutes or fitting a lower-flow head can drop the monthly household total by tens of pounds when several people shower daily.
Limits and assumptions
Heating efficiency varies widely; electric showers and heat pumps need different energy factors. Standing charges are not allocated per shower. Water and sewerage volumetric charges are often small versus heat but are omitted unless you add them.
Frequently asked questions
Why is heating more expensive than water?
Heating a litre of water takes far more energy cost than the volumetric water charge in most UK homes.
How do I find shower flow rate?
Timing how long a bucket takes to fill, or reading the shower’s rated litres per minute, both work.
Do shorter showers always save a lot?
Cutting minutes helps linearly in this model. Low-flow heads can save more without rushing.
Does Economy 7 change the maths?
If you heat a cylinder overnight on a cheap rate, use that blended heat cost rather than the daytime unit rate.
Are baths comparable?
A full bath often uses more hot water than a short shower. Run similar litre and tariff assumptions to compare.