Your natural waist is the smallest point around your middle. Not sure where it is? Bend to the side — the crease that forms is your natural waistline. You could also wrap a piece of elastic around your waist, letting it rest at the spot that feels comfortable. Wear it for a bit to ensure that it feels natural, and if it does, use that point for your measurement.

Pro tip: Your natural waist measurement isn’t necessarily where you’ll wear your pants. If you want them to sit above or below your natural waist, take that measurement too, so you can compare it to the pattern later. (From here on in, when we refer to “the waist,” we’re referring to the place where you plan to wear your pants. Which, again, may or may not be your natural waist.)

2. High Hip

The high hip is the point around your upper butt and across the fullest point of your lower belly (it will likely cross your belly button). After jotting that number down, measure the distance from the waist to the high hip to compare to the pants pattern later.

3. Full Hip

The full hip is just above your crotch and below your belly button. As with the high hip, also measure from the waist to this point for later reference.

4. Upper Thigh

Measure the circumference around your thigh, just below your crotch.

5. Thigh

Also measure the circumference of your thigh at the midpoint, between your crotch and knee. This, along with the upper thigh measurement, will help you make sure your pants fit well through the thigh, as you may find you need to blend between sizes.

6. Calf

Measure your calf around its fullest point. Don’t underestimate the importance of this step; calf sizes can vary dramatically, even among two people who wear the same pant size (not to mention one calf could be bigger than the other). Just as with the thigh, you can use this info later to blend between bigger or smaller sizes if necessary.

7. Ankle

If your pants are designed to be fitted at the ankle, this is a pretty important number. Measure at the point where you want the pants to hit.

8. Length

To measure pant length, you need to take note of a couple places. First, measure the distance down the side of your body, from the waist to where you want the pants to end when hemmed. Then, measure from the crotch to that same spot. Finally, put on the shoes you plan to wear with the pants and see if the length you’ve selected still works. If not, adjust accordingly.

9. Crotch Length

Start with the tape measure at the waist, bring it down under your crotch, up around the curve of your butt and back up to the waist in back. It’s key to include any curves of the belly and butt into this measurement; otherwise, your pants will feel too snug.

10. Crotch Depth

This is the distance from the waist to the crotch. Again, be true to your curves to make sure it fits correctly.