Yes, you can get a blood clot in your calf, and it’s actually one of the most common locations for clots to form. Blood clots in the deep veins of the lower leg are a type of deep vein thrombosis (DVT), which affects roughly 5 to 10 out of every 10,000 people each year. Clots in the calf often start in the small veins of the soleus muscle, a deep muscle behind your shin, where blood flow is naturally slowest.
Why Clots Form in the Calf
Your calf muscles act as a pump for blood returning to your heart. When you’re sitting, sleeping, or otherwise not moving your legs, blood pools in the lower leg, particularly in the small venous pockets behind the valves inside your veins. This slow-moving blood is more prone to clotting.
Three conditions make a clot more likely: damage to the vein wall, sluggish blood flow, and blood that clots more easily than normal. These factors rarely act alone. A long flight combined with dehydration, for instance, hits two of the three at once. Surgery is one of the strongest triggers because it involves all three: tissue damage, prolonged immobility during and after the procedure, and an inflammatory response that makes blood stickier.
Who Is Most at Risk
Some risk factors are temporary and others are built in. The major ones include:
- Recent surgery or injury, especially to the leg, hip, or knee. Longer surgeries carry higher risk.
- Immobility, whether from bed rest, a leg cast, long-distance travel, or a sedentary hospital stay of three days or more.
- Age over 55, which roughly triples the odds compared to younger adults in surgical populations.
- Active cancer, which changes the blood’s clotting chemistry. People with active cancer remain at elevated risk for as long as the disease is present.
- Female sex, partly because pregnancy and hormonal birth control both increase clotting tendency.
- Previous DVT, which is one of the strongest predictors of a future clot.
- Inherited clotting disorders like factor V Leiden or protein C and S deficiencies.
Having multiple risk factors at once raises your chances significantly. A 60-year-old woman recovering from knee surgery in a hospital bed, for example, checks several boxes simultaneously.
What a Calf Blood Clot Feels Like
The classic symptoms are swelling, pain, warmth, and redness in the affected leg. The pain often feels like a deep cramp or soreness that gets worse when you stand or walk. Some people notice the swelling first, particularly if one calf looks noticeably larger than the other. A difference of 3 centimeters or more between your calves, measured about 10 centimeters below the knee, is a red flag doctors specifically look for.
Not everyone gets all four symptoms. Some calf clots produce only mild tenderness or a vague feeling of tightness. Others cause no symptoms at all and are discovered incidentally during imaging for something else. The key pattern to watch for is symptoms that appear in one leg only. Soreness in both calves after a long hike is muscle fatigue. Swelling, pain, and warmth in just one calf is a different story.
How Calf Clots Are Diagnosed
When you describe these symptoms to a doctor, they’ll typically start with a scoring system called the Wells criteria. This adds up your risk factors (active cancer, recent surgery, leg swelling, tenderness along a deep vein, prior DVT, and others) to estimate how likely a clot is. A score of 0 or below means low probability; 3 or higher means high probability.
The primary imaging test is a compression ultrasound, where a technician presses the ultrasound probe against your leg veins. A healthy vein collapses flat under pressure. A vein containing a clot doesn’t. When performed by an experienced technician or physician, this test has sensitivity and specificity both above 96%, making it highly reliable. A blood test that detects a protein fragment released when clots break down can also help rule out DVT. If that blood marker comes back negative and your clinical risk score is low, a clot is very unlikely.
Calf-level clots can be trickier to spot than clots higher in the leg. Ultrasound accuracy drops somewhat below the knee, so if initial results are unclear but suspicion remains, your doctor may repeat the scan in about a week to check for any change.
How Serious Is a Calf Clot
The biggest concern with any DVT is that part of the clot could break free and travel to the lungs, causing a pulmonary embolism. For clots isolated to the calf, this risk is relatively low. Research reviews place the rate of pulmonary embolism from isolated calf DVT between 0% and 6.2%, with no fatal cases reported in those studies. That’s reassuring compared to clots in the thigh or pelvis, which carry a higher embolism risk.
The more common long-term problem is post-thrombotic syndrome, a condition where the clot damages the vein’s valves and walls, leading to chronic swelling, pain, skin discoloration, and sometimes ulcers in the affected leg. This develops in 20% to 50% of people who’ve had DVT, with about half of cases appearing within the first year. Severe post-thrombotic syndrome affects 5% to 10% of DVT patients. Clots limited to the calf generally cause milder long-term damage than those in larger veins, but the risk isn’t zero.
Treatment and Recovery
Blood thinners are the standard treatment. These medications don’t dissolve an existing clot, but they prevent it from growing and give your body’s natural clot-dissolving system time to work. How long you’ll need to take them depends on what caused the clot in the first place.
If your clot was provoked by a clear, temporary trigger like surgery, a leg injury, or a period of immobility, a typical course is 3 months of blood thinners. Once the trigger is gone, your risk of recurrence drops, and stopping treatment after that window is usually reasonable.
If your clot appeared without an obvious cause (called unprovoked or idiopathic DVT), the picture changes. These clots have a higher recurrence rate, and guidelines often recommend indefinite blood thinner therapy, particularly if your bleeding risk is low. Your doctor may periodically recheck your clot-related blood markers to help decide whether it’s safe to stop. People with inherited clotting disorders or active cancer also typically stay on treatment longer.
During treatment, you’ll need periodic monitoring, and you should be aware of the increased bleeding risk that comes with blood thinners. Cuts may take longer to stop bleeding, and bruising becomes more common. Most people tolerate these medications well, but you’ll want to discuss any planned surgeries or dental procedures with your doctor while you’re on them.
Reducing Your Risk
Movement is the single most effective thing you can do. Your calf muscles squeeze blood upward through the veins every time you flex your feet or walk, counteracting the pooling that leads to clots. On long flights or car rides, getting up to walk every hour or two, or simply pumping your ankles up and down while seated, makes a meaningful difference.
Graduated compression stockings, which apply the most pressure at the ankle and gradually less pressure up the leg, are effective at preventing DVT in hospital patients after surgery. A Cochrane review found high-quality evidence that these stockings reduce DVT risk in people recovering from general and orthopedic surgery. They work by pushing blood from superficial veins into the deeper system, increasing flow velocity and reducing the pooling that triggers clots.
Staying hydrated, maintaining a healthy weight, and avoiding prolonged periods of sitting also help. If you’re heading into surgery or a hospital stay, your care team will likely use a combination of compression stockings, blood-thinning injections, and early mobilization to keep your risk as low as possible.