There’s no set amount of swelling that counts as normal. But there are clear patterns to watch for.
Some swelling is part of healing. After a scab forms, your immune system starts protecting the wound. In this stage the wound becomes slightly swollen, red or pink, and tender. This stage takes about 2 to 5 days.
Slightly. And within a window.
After that, swelling means something different. Swelling is on every list of infection signs, and usually as a change. Redness, increased warmth, or swelling around the wound. Skin close to the sore that is warm or swollen. After surgery, swelling or bleeding is among the changes to contact your surgeon about.
On a leg the picture is different again, because swelling may come from an underlying condition rather than the wound. Leg swelling, heaviness and cramping are among the early signs of venous insufficiency. The skin around a venous ulcer may be shiny, tight, warm or hot, and discolored.
So there are three patterns: slight swelling in the first few days of healing; swelling that is new or increasing, which is a sign of infection; and longstanding leg swelling, which is a sign of blood pooling.
None of that gives you a measurement. What helps in practice is comparison rather than amount — against the other limb, or against how it looked a few days ago.
Wound Wizard has a separate article on a leg that is swollen around a wound, which goes into the leg case in more detail.