How do I use the hydration scale?
This 8-step scale, used in sports medicine, is based on research showing that urine colour roughly reflects the body’s water balance (Armstrong et al., 1994). Compare a urine sample from during the day (not the first one in the morning) against the scale, on a white background or in a clear container.
- 1
- 2
- 3
- 4
- 5
- 6
- 7
- 8
- 1–3: Well hydrated
- 4–5: Drink a little more
- 6–8: You may be dehydrated, drink water now
The scale is a rough guide for healthy adults; vitamins, medicines and foods can change the colour. If you have been told to limit fluids because of heart or kidney failure, do not exceed the amount your doctor recommends.
What colour should normal urine be?
Healthy urine is usually somewhere between pale straw and transparent yellow. The colour comes from a pigment called urochrome, produced when old red blood cells are broken down. The more you drink, the more diluted and lighter your urine becomes; when you drink less, it becomes concentrated and darker. That is why the colour changes during the day; the first urine in the morning is usually the darkest.
Why does urine change colour?
Most colour changes are harmless and come down to four main causes:
- Fluid balance: Drinking too little, hot weather, sweating, fever or diarrhoea make urine darker.
- Foods: Beetroot, blackberries and rhubarb can turn it pink or red; broad beans brown; large amounts of carrots orange.
- Vitamins and medicines: B vitamins can make it bright yellow; rifampicin and phenazopyridine orange-red; amitriptyline, methylene blue and propofol blue-green. If the colour changed after starting a new medicine, read the patient leaflet and do not stop the medicine on your own.
- Medical conditions: Blood in the urine, urinary tract infection, kidney stones, liver disease, muscle breakdown (rhabdomyolysis) and kidney disease can change the colour and appearance.
When is red or brown urine dangerous?
Visible blood in the urine (macroscopic haematuria) should always be taken seriously. It can be painless and can appear once and then disappear; that does not mean the underlying cause has gone. According to the European Association of Urology (EAU) guidelines, blood in the urine is the most common sign of bladder tumours, and the risk rises with age and smoking. The NHS likewise advises getting even a small amount of blood checked, even if it is the first time and you have no other symptoms.
A simple urine test shows whether a red colour comes from beetroot or a medicine, or from blood. If blood is confirmed, the urology assessment may include an ultrasound, a CT scan and, where needed, cystoscopy (a camera examination of the bladder), depending on your age and risk factors. Brown or cola-coloured urine, unless it is clearly due to severe dehydration, should be assessed the same day for liver, muscle and kidney causes.
When should I see a doctor straight away?
- Clots in the urine, or bleeding with inability to pass urine
- Red or brown urine with fever, shivering or pain in your side
- Cola-coloured urine with muscle pain after strenuous exercise or an injury
- Dark urine with yellowing of the eyes or skin
- Very little urine despite drinking, with dizziness or confusion
Related pages
This chart is for information only and does not provide a diagnosis. The cause of a change in urine colour can only be established with an examination and a urine test.