
- Organ Name: Kidney
- Organ Location: Upper abdominal cavity
- Organ System: Urinary system
- Organ Purpose: Filter blood, blood pressure regulation and red blood cells
- Organ Weight: Between 1.4 and 6.2 ounces
- Organ Size: About the size of a human fist
22 Kidney Facts for Kids
- Kidneys are organs that are shaped like beans and are part of the urinary system in humans.
- Kidneys filter the blood by removing waste and excreting it via urine (pee).
- Kidneys help keep a stable balance of fluids in your body.
- Kidneys help keep your blood pressure at a normal level.
- Kidneys produce hormones that aid in the production of red blood cells.
- At birth a genetically normal human has two kidneys.
- The right kidney is slightly smaller than the left kidney to make room for the liver.
- Kidneys are in the upper area of the human abdominal cavity, with one on each side of the spine.
- The average weight of a healthy male adult human kidney is between 2.8 and 6.2 ounces.
- The average weight of a healthy female adult human kidney is between 1.4 and 6.7 ounces.
- Kidneys filter around 37.5 gallons of blood every day or about 1.5 gallons every hour.
- Kidneys filter the entire blood volume in the human body between 20 to 25 times per day.
- Kidneys produce between 0.25 and 0.5 gallons of urine every day.
- Humans don’t need both Kidneys to survive. You can live a completely healthy life with just one kidney.
- A kidney stone is a solid piece of material that develops in kidneys.
- Kidney stones can be quite painful and if they’re large enough may require surgery to be removed.
- Abdul Abu Al Hajjar holds the record for the largest kidney stone. In 2017, he had a kidney stone removed that weighed 4.4 pounds in Kensington, England.
- Donald Winfield holds the record for the most kidney stones passed without needing surgery, a whopping 5,704.
- A kidney transplant is a surgical procedure where a living or deceased donor’s kidney is removed and put into another human who has end-stage kidney disease.
- The United States had over 16,500 kidney transplants in 2008.
- The first attempt to surgically transplant of a human kidney was in 1933, by Yuri Voronoy.
- The first successful attempt to surgically transplant of a human kidney was in 1954, Joseph E. Smith.
Human Kidney Pictures

A diagram of the human kidney.Credit: Stanford Childern’s Health

An MRI image of a human kidney.Credit: Anil Karihaloo

An image of human kidney stones.Credit: University of Chicago
Additional Resources on the Human Kidneys
- The Anatomy of Human Kidney – View the anatomy of the human kidney on the Oregon State University.
- How the Human Kidneys Work – Learn how the human kidneys work on the National Kidney Foundation website.
- List of Kidney Diseases – A complete list of diseases and disorders that affect the human kidneys on the MedlinePlus website.
- Kidney – Wikipedia – Discover more cool facts and information about the kidneys on the Wikipedia website.