Measurement Instructions
Get in touch if you have questions
Reach out to us at sizing@fluxchastity.com if you have any questions about the measuring process.
Materials Needed
You can assemble these tools yourself, or get them in the Flux measuring kit. The measuring kit has everything needed and includes a discount for its cost (excluding shipping) when you order a belt.
- A belt, 35-40mm (1.4-1.6 inches) wide. Most leather pants belts will be suitable. It must be made from a material that does not stretch.
- A tailor’s tape measure. (Do not use a stiff metal construction tape measure, as this may give inaccurate numbers when measuring curved body parts.)
- A set of transfer calipers large enough to measure the width of your hips. The measuring kit comes with a 3D printed set of calipers. If you would like to purchase your own, we recommend searching for a set of "Martin breadth calipers"
- A marker. Caution: The marker included with the measuring kit is made to make long lasting marks on skin. It will generally take a few days for marks to wash off completely. This will make it easier to take consistent measurements between sessions, but if you prefer something easier to remove, you can use a washable marker instead.
- The measurement recording form.
- Optional: A friend or partner to help. It is possible to take measurements solo, but having a helper will make the process easier.

Measuring Process
General Measuring Tips
- All measurements should be taken in a relaxed standing position.
- Measurements should be snug to your body, but not so tight as to be uncomfortable.
- Measurements should be taken against the skin, not over clothes. (Clothes in the demonstration photos are for modesty only.)
- Take the measurements twice, on two separate days, to double-check for consistency.
- Specify whether your measurements are in inches, centimeters, or millimeters (preferred) in the Units field of the measurement recording form.
How to Measure
Hip Circumference and Rise-
Measure the precise width of your belt, record this as the Actual belt width. For the belt included with the measuring kit, this number is 38 mm.
- Fasten the belt over your hips at a comfortable and natural height, like the waistband on a pair of low-rise pants. The top of the belt should go across your body as close to level and horizontal as possible. Place the buckle of the belt slightly off to one side, to make taking measurements easier. (Note that the Flux comfort chastity belt is meant to sit at the hips, not the waist.)
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Use your tailor’s tape measure and wrap it snugly around your body immediately above the top of the belt. The tape should be touching your skin, not overlapping the belt. Record this number as the Hip circumference.
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Measure from the top edge of the belt in front to the top edge of the belt in the rear, passing the tape between your legs. Pull the measuring tape snug, but do not pull down on the belt. The tape measure should be tight to your body but not pressing in deeply or giving you an extreme wedgie. Record this measurement as the Rise.
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Locate your anus. Measure from your anus to the top of the front of the belt. Record this measurement as the Tape measure front to anus on the measurement recording form.
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Locate your anus. Measure from your anus to the top of the rear of the belt. Record this measurement as the Tape measure rear to anus on the measurement recording form.
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Add the Tape measure front to anus and Tape measure rear to anus measurements together. The sum should equal the Rise measurement. If it does not, double check these three measurements. (A small variation of up to 10mm or 3/8" is acceptable.)
- Put on a belt just as in the instructions for measuring hip circumference and rise.
- Use the tips of your calipers to find the widest spot on your hips immediately above the belt. When taking measurements with the calipers be sure to avoid digging the tips into your body too tightly. Lock the calipers by tightening the knob at the pivot point, and use your tape measure to measure the distance between the tips. Record this as the Hip width.
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Use the calipers to measure yourself from front to back. Put one tip just above the belt in the small of your back, right above where your back belt loop would go. Put the other tip just above the belt on your belly, right above where your fly button would go.. Lock the calipers and use your tape measure to measure the distance between the tips. Record this as the Hip depth.
- Choose a spot over your pubic bone, immediately above your vulva. Mark this spot with the marker. The exact location isn't important as long as the spot is over your pubic bone and consistent between measurements. Use the calipers to measure from both the front and rear points used in step 3 to this location while resting the tip gently on this spot. Record these measurements as Mons to front and Mons to rear.
- Make the same measurements as in step 4, but this timepress the caliper tip more firmly into the spot you marked. Record these measurements as Pubic bone to front and Pubic bone to rear.
- Find your anus. Use the calipers to measure from both the front and rear points used in step 3 to this location while resting the tip gently on this spot. Do not insert the tip of the calipers. We’ve included a finger cot you can use to cover it for cleanliness, but the whole caliper should stay outside your body. Record these measurements as Caliper anus to front and Caliper anus to rear.
Measurement | First Measurement | Second Measurement |
Actual Belt Width | ||
Hip Circumference | ||
Rise | ||
Tape Measure Front To Anus | ||
Tape Measure Rear To Anus | ||
Hip Width | ||
Hip Depth | ||
Mons To Front | ||
Mons To Rear | ||
Pubic Bone To Front | ||
Pubic Bone to Rear | ||
Caliper Anus to Front | ||
Caliper Anus to Rear |