For medium-rare, you’re aiming for an internal temperature of 130°F to 135°F (54°C to 57°C). An instant-read thermometer is your most reliable tool—don’t guess if you can measure. Insert it sideways into the thickest part, away from bone.
If you’re without a thermometer, use the hand test: touch your thumb to your index finger, then press the fleshy pad below your thumb. That’s what medium-rare feels like—a firm but yielding spring. Compare it to the steak’s center; you’ll feel the same give.