Tap Flow Rate Calculator
Litres (L)
Gallons (US)
Milliliters (ml)
Kitchen Faucet
Bathroom Faucet
Shower Head
Flow Rate (Metric):
0 L/min
Flow Rate (Imperial):
0 GPM
Hourly Consumption:
0 Litres
Efficiency Rating:
What is Tap Flow Rate and Why Measure It?
The flow rate of a tap (faucet) or showerhead refers to the volume of water that passes through the fixture in a specific amount of time. It is most commonly measured in Litres per Minute (L/min) or Gallons per Minute (GPM).
Understanding your flow rate is the first step in auditing your home's water efficiency. A standard older tap might release 15-20 litres per minute, whereas a modern, water-efficient tap equipped with an aerator typically flows at 6-9 litres per minute. By calculating your flow rate, you can determine if installing flow restrictors or aerators could save you money on water and energy bills.
How to Use This Calculator (The "Bucket Test")
You don't need expensive equipment to measure your tap's efficiency. Follow these simple steps to get the data needed for the calculator above:
- Step 1: Get a measuring jug or a bucket with clear volume markings (e.g., a 1-litre measuring jug or a 10-litre bucket).
- Step 2: Get a stopwatch (or use the timer on your phone).
- Step 3: Turn your tap on fully. If you are measuring a mixer tap, turn it to the setting you normally use.
- Step 4: Simultaneously place the container under the stream and start your timer.
- Step 5: Stop the timer the moment the water reaches your target volume mark.
- Step 6: Enter the volume of the container and the time it took to fill into the calculator above.
Interpreting Your Results
Once you calculate your flow rate, compare it against these industry standards to see how efficient your fixtures are:
Bathroom Faucets
- High Efficiency: < 4 L/min (1.0 GPM)
- Standard: 4 – 6 L/min (1.0 – 1.5 GPM)
- Inefficient: > 8 L/min (2.0 GPM)
Kitchen Faucets
- High Efficiency: < 6 L/min (1.5 GPM)
- Standard: 6 – 8 L/min (1.5 – 2.2 GPM)
- Inefficient: > 10 L/min (2.5 GPM)
Showers
- High Efficiency: < 7.5 L/min (2.0 GPM)
- Standard: 9.5 L/min (2.5 GPM)
- Inefficient: > 12 L/min (3.0 GPM)
How to Improve Tap Efficiency
If the calculator indicates your tap has a "High Flow" rate, the most cost-effective solution is to install a tap aerator. An aerator screws onto the tip of the faucet and mixes air with the water stream. This maintains strong pressure and reduces splashing while significantly cutting down water usage—often by up to 50%.