Body Armor Sizing Guide - How to Select Proper Rifle Plate and BALCS Armor Size

As there is currently no published, universal guide to fitting yourself for body armor I will be doing my best here to create such a guide. It should be noted in advance that choosing the appropriate size for armor, including both soft armor and rifle plates, involves multiple variables and can be a highly individualized process. That said this guide is designed to be as general as possible but there are always exceptions to the rule, so if possible it is best to test fit actual armor before committing to a purchase.

All dimensions called out here are in inches.

Sizing yourself for hard armor –

There are two hard armor size systems used for “full size” torso plates in the U.S. – the non-standardized ‘LEO’ size system and the standardized SAPI size system developed by the U.S. military. The LEO (referring to law enforcement) size system was developed by the armor industry in the early days of commercial hard armor in an effort to create a universal industry standard size system. However, it is an informal standard not enforced by anything except the fact of convenience for commercial armor manufacturers. As such plates made to any of the three sizes under the LEO size system can have any variety of cuts and actual dimensions can be off by as much as a full inch.

The SAPI size system however is fully standardized, with every dimension specced under a published standard. This system is enforced by the fact that DoD (Department of Defense) requirements are strict, so there is little to no variance in plate dimensions or cut style among SAPI sized plates regardless of type or manufacturer. Commercial armor intended to be sold to users in the U.S. military must meet the SAPI dimensional specs or it will not interface properly with issued equipment. As the U.S. military is the single largest buyer of body armor in the world the SAPI size system has become the de facto standard for hard armor sizing in the U.S., next to the LEO system.

The LEO system is composed of three sizes, 8x10, 10x12, and 11x14. Plates in 10x12 are extremely common and as such so are carriers made for them.

8x10 is considered the “Small” size, 10x12 “Medium”, and 11x14 “Large”. Most adult American males will find the 10x12 size to be adequate.

To size by chest size (circumference, as measured around fullest part of chest as illustrated below) for the LEO system, you would follow this chart –

8x10: chest size of 37” or below.

10x12: chest size of 37” to 45”

11x14: chest size of 45” or larger.

Note that these are generalities based upon the SAPI size system as there was never a fitting standard developed for the LEO system, so I have done my best to adapt the measurements used in the SAPI system to the LEO system.

To size by chest size for the SAPI system, you would follow this chart:

Extra Small: chest size of 33” or below

Small: Chest size of 33” to 37”

Medium: Chest size of 37” to 41”

Large: Chest size of 41” to 45”

Extra Large: Chest size of 45” and up.

This fitting system was determined by the U.S. military.

SAPI plate dimensions are shown below –

To measure your chest circumference, measure around the fullest part of your chest as shown:

Use a cloth tape measure or other flexible measuring device to get your chest circumference in inches.

Ensuring proper plate fit –

To ensure proper plate fit it is best to make a cardboard (similar stiff materials can be used as well) cutout of the plate sizes/cuts you’re interested in to physically check for proper coverage and fit.

To properly orient the plate on the vertical axis, stick your pointer finger in your suprasternal notch. Then take the plate and bump the top of the plate into your finger. This is illustrated below.

Proper placement of the front plate is typically on that spot or within two finger widths of it if you desire to lower the plate slightly.

Now you can check for coverage of vitals (heart, lungs, major arteries) and other organs such as the diaphragm. There is no hard rule for what exactly a plate should cover as armor is always a balance of protection vs. weight and ergonomics.

To check for ergonomics, punch out with your arms as if shooting a handgun. Shoulder and arm movement through that range should not be impeded. Also be sure to bend over and/or go into a deep crouch to check if the plate digs in or contacts your belt area or thighs. If it does it may jam up into your neck or chin. If you find the plate does this when you crouch or bend over, it is likely too long. You should be able to comfortably crouch, bend over, and your arms should not be impeded through the majority of their range of motion with a properly sized plate.

Some users opt to go down one plate size for the purposes of decreasing weight and improving ergonomics. So for example a user whose technically correct plate size is SAPI Medium might choose to wear SAPI Small plates for the aforementioned reasons. Naturally the sacrifice being made is coverage, but some users determine that unimpeded movement and weapon manipulation is more important for their purposes than maximizing coverage. As always you should adapt your gear to your specific needs if possible.

Sizing yourself for soft armor –

This is a much more complicated matter as there is a wide array of soft armor options and multiple size/cut styles, especially in regards to law enforcement style concealable armor. That said, I will cover one fairly common system here and that is the BALCS system.

BALCS (Body Armor Load Carriage System) is another U.S. military designed armor system and as such is a rigid standard, meaning little to no variation between models and manufacturers in terms of the dimensions of their armor.

As BALCS was designed to work with other U.S. military armor systems – including issued SAPI plates – it follows the SAPI size system in terms of sizing based on chest size. That said one need only refer to the SAPI size system as described above to determine the appropriate size of their BALCS soft armor.

Again, this can vary however. I for example am technically sized for SAPI Small and Small BALCS. However, I can easily wear Medium BALCS and in fact prefer the coverage it offers over Small BALCS soft armor. So if I were to combine my preferred SAPI rifle plate size and preferred BALCS soft armor size I would wear a Small SAPI plate with Medium BALCS armor.

A note of caution on this however – most BALCS carriers that also offer an option to carry plates will typically have the plate pockets sized for the corresponding SAPI size, meaning a Small BALCS soft armor carrier with plate pockets will most likely have SAPI Small plate pockets. Some made-to-order or custom manufacturers like Beez Combat Systems however can customize carriers to mix and match sizes.

Conclusion –

Sizing yourself properly for body armor is not difficult as long as you have the appropriate information and follow a few steps to physically check fit before committing to buy. As always there are exceptions to any rule and if you have the experience necessary to make a highly informed decision regarding your body armor then it may be in your interest to break from these rules to better suit your particular situation, but otherwise I generally recommend following the guidelines I’ve laid out here for choosing the size of your body armor.

Stay safe, stay informed, and don't forget to check out the blog for more articles on body armor and related subjects.

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