If this is your first winter blanketing your horse, all the terms and numbers when looking for your first blanket might seem a little overwhelming. There are many different types and styles of blankets, and each one is meant for a different use. Not every horse needs to be blanketed - it depends on the individual horse itself, and the type and level of work they will be doing over the winter. But if you do determine that your horse needs some type of blanket this winter, figuring out which blanket is the right one for your horse is important.
The most important number to understand is the size of the blanket. Depending on the brand, blankets will either be measured in 2" or 3" increments. If your horse is in-between sizes, it's always best to go a size up rather than a size down. Your horse's size is measured from the front of their chest to the point of their butt. Measuring can sometimes be tricky, and you will most likely need a friend to help you, so make sure to measure 2 or 3 times to be accurate!
The denier of a blanket is the strength of the outer layer. If you have a horse that is hard on his blankets, or his turnout buddies always seem to enjoy his blanket as a snack, then you'll want a higher denier. 1200D or 1600D is what you'll want to look at for a horse that tends to rip their blankets. Some blankets will even go up to 2100D!
Fill refers to how warm/heavy the blanket is. There are 4 basic weights of blankets - sheets, light, medium, and heavy. Sheets will have a 0gm fill, or 'no fill'. This means there is no weight or insulation to the sheet, and it is used more for wind protection or for a base layer under another blanket. A lightweight blanket will have a fill under 100gm, a midweight/medium weight blanket will have a fill under 200gm, and a heavyweight will have a fill under 400gm.
A blanket liner is a lighter blanket or sheet that is used for layering purposes under a heavier blanket. A liner can be a fleece dress sheet or cooler, a knit sheet, or a stable blanket.
Another important difference to learn is between a turnout blanket/sheet, and stable blanket/sheet. Turnout blankets are waterproof, and are meant for the horse to wear outdoors and in turnout. A stable blanket is not waterproof, and is meant for indoor use, or for an extra layer under a turnout blanket.