How long does the hot water last when taking a shower?

I sometimes have arguments with the rest of my family because there is often not enough hot water for us all to have a shower in the morning. When we all need to have a shower I would like to know how long each of us can spend in the shower depending on the size of our water tank which is 75 litres. Can you calculate how long the water the water will last?
Please fill in the form below with your own values then click the button to see the results.
Hot water flow: litres per minute
A perfectly acceptable flow of water is 5 or 6 litres of water per minute. 8 litres per second would be a very strong power shower and a waste of water.
Cold water flow: litres per minute
I always fit automatic mixer taps in my house because there is nothing worse than being scalded one minute, making an adjustment and then being frozen by a jet of cold water.
Size of Water tank: litres
The most common size of domestic water tank is 75 litres.
Hot water temperature: Centigrade
Most hot water tanks are set to around 65C becuase it is hot enough to kill the Legionella bacteria which can cause pneumonia and not hot enough to cause scalding.
Cold water temperature: Centigrade
The water temperature in the mains can vary from summer to winter and from different locations. 11C is the average but it is a good idea to take the temperature of your mains water with a thermometer to get correct results.
Length of shower: minutes
For most people 5 minutes is enough time to wash the hair and body.