# Shower Water and Energy Calculator

URL: https://speedycalculator.com/calculators/ecology/shower-water/
Last updated: 2026-10-25

> The shower calculator estimates the water, energy, cost and CO₂ of your showers from their length, the shower’s flow rate and how many showers you take, and shows savings from shorter showers.

## Inputs

- Shower length (minutes)
- Flow rate (L/min, US gal/min)
- Showers per week
- Water heated by (°C)
- Energy price per kWh

## Results

- Water per shower
- Energy per shower
- Water per year
- Heating cost per year

## Formula

```
Water = minutes × flow rate
Energy = water × 4.186 kJ/kg·K × temperature rise
```

## Explanation

Heating water is one of the biggest energy uses in a home. A low-flow head or one minute less makes a measurable difference.

### How to use the Shower Water and Energy Calculator

- **Shower length**
- **Flow rate**
- **Showers per week**
- **Water heated by**
- **Energy price per kWh**

Results update as you type, and every field accepts the units shown in its menu.

### How it works

Water volume comes from time and flow; the energy to heat it comes from its specific heat and the temperature rise.

### Inputs explained

FieldWhat to enterShower lengthIn minutesFlow rateUnits: L/min, US gal/minShowers per weekA numberWater heated byIn °CEnergy price per kWhAmount in your currency

### What each result means

- **Water per shower** = [Shower length]×[Flow rate]
- **Energy per shower** = [Water per shower]×4.186×[Water heated by]÷3600
- **Water per year** = [Water per shower]×[Showers per week]×52
- **Heating cost per year** = [Energy per shower]×[Showers per week]×52×[Energy price per kWh]

### Example values

How the main result changes when **Shower length** changes and everything else stays at the example values above:

Shower length (minutes)Water per year (L)413,104619,656826,2081032,7601239,3121652,416

## Worked example

Inputs — Shower length: 8 minutes; Flow rate: 9 L/min; Showers per week: 7; Water heated by: 30 °C; Energy price per kWh: $0.18.

Results — Water per shower = 72 L; Energy per shower = 2.51 kWh; **Water per year = 26,208 L**; Heating cost per year = $164.56.

## FAQ

**What flow rate is typical?**
Older showers 10–15 L/min; low-flow heads 6–8 L/min.

**Does this include heater efficiency?**
No; divide energy by your heater efficiency for a closer estimate.

**What formula does the Shower Water and Energy Calculator use?**
Water = minutes × flow rate.