Your kidneys sit much higher than most people expect. They’re tucked behind your stomach, up under your rib cage, roughly at the level of your lowest ribs. Many people assume kidneys are down near the hips or belt line, but they actually sit in the upper back area of your abdomen, closer to the middle of your torso than the bottom.
Exact Position in Your Body
Each kidney sits against the muscles of your back wall, behind all of your intestines and stomach, in a space called the retroperitoneal area. Think of them as being sandwiched between your back muscles and the rest of your abdominal organs. The upper third of each kidney is covered by your diaphragm (the breathing muscle that separates your chest from your abdomen), and the 12th rib, your lowest rib, crosses over the top of each kidney. That means the upper portions of your kidneys are actually behind the rib cage, partially protected by bone.
If you reach around and place your hands on your back just above your waist, with your fingers pointing toward your spine, your kidneys are roughly behind your hands. They sit on either side of your spine, one on the left and one on the right.
Why One Kidney Sits Lower Than the Other
Your right kidney sits slightly lower than your left. This is because the liver, which is a large organ on your right side, pushes down on the right kidney. The upper right pole of the kidney actually connects to the space behind the liver. The difference is small but consistent across most people.
In terms of size, the left kidney is also slightly larger. Ultrasound studies of healthy adults show a median length of about 11.2 cm on the left and 10.9 cm on the right, with the left kidney having a slightly greater volume as well. Each kidney is roughly the size of your fist.
Your Kidneys Move When You Breathe
Because the diaphragm sits directly above the kidneys, every breath pushes them downward slightly. During a deep inhale, each kidney can shift about 1.5 to 4 centimeters lower than its resting position. The right kidney, which sits closer to the liver and diaphragm, tends to move in a similar range as the left. This is normal and one reason why imaging studies sometimes ask you to hold your breath: it keeps the kidneys still long enough to get a clear picture.
How to Tell if Pain Is Coming From Your Kidneys
Because kidneys are higher and deeper than people realize, kidney pain often gets confused with upper back pain or a pulled muscle. The key difference is location. Kidney pain shows up in your flank, the area on either side of your spine just below your ribs. It typically feels deep, not surface-level, and doesn’t change when you shift positions or stretch the way a muscle strain would.
The spot doctors press to check for kidney problems is called the costovertebral angle, which is the point where your lowest rib meets your spine on each side. If pressing firmly on that spot produces sharp pain, it can suggest a kidney infection or a kidney stone. This tenderness at the costovertebral angle is one of the most common physical exam techniques used in emergency departments to distinguish kidney issues from other causes of back or abdominal pain.
Kidney pain also tends to be one-sided, since most conditions like stones or infections affect one kidney at a time. It can radiate toward your abdomen or groin, especially with kidney stones, which is another way to distinguish it from a simple backache.
When Kidneys Aren’t in the Usual Spot
In a small number of people, one or both kidneys never migrate to their normal position during fetal development. The most common variation is a pelvic kidney, where the organ stays low in the pelvis near the bladder instead of rising to its usual spot under the ribs. When imaging reveals an empty space where a kidney should be, about 42% of the time the kidney is simply in an ectopic (out-of-place) location rather than missing entirely. Pelvic kidneys tend to be smaller, oriented diagonally or horizontally, and harder to spot on ultrasound. In rare cases, both kidneys end up in the pelvis. Most people with a pelvic kidney have no symptoms and may never know unless it’s found incidentally on an imaging scan.