Your jeans should sit at the waist without needing a belt. Once you need a belt, the pants are too big. They should be tight, but not skin-tight on your legs. Most wearers want to avoid a flare look, so the leg shape should remain recognizable. If you can't squat down without feeling like the jeans are going to rip, they are definitely too tight. A pinch test is also helpful to determine the right fit: To do this, stand relaxed and pinch the fabric between your thumb and index finger. This should cover about a fingertip. If it is less, the pants are too tight, if it is more, they are too wide. You can also use this test on your calves.