Hoof Boot Size Calculator

Fill in the fields above and press Work out the boot size.

Two brands, two numbers, one foot

Blanket sizing has one number and a labelling argument. Hoof boot sizing has neither: each maker builds a different shell around a different trim philosophy, so the size number is theirs alone.

A hoof measuring 125 mm wide by 135 mm long comes out as Cavallo size 4 and Renegade Classic size 2. Both are correct. Neither transfers to a third brand, and a boot bought by size number alone rather than by measurement is a coin flip.

Never order a hoof boot by the number on your old pair. Even a replacement of the same model should be re-measured, because the hoof changes shape across the trim cycle.

Measure after a trim, and leave the bulbs out

Hoof boot sizing is the one measurement on this site where the timing matters as much as the tape. Measure after a fresh trim, on the day you intend to order.

Measurement	Where it goes	The mistake that costs a size
Hoof width	Across the widest part of the hoof	Measuring above the widest point, on the hairline
Hoof length	Heel buttress line to the toe	Including the heel bulbs — adds 5–10 mm and drops you a size

Measure all four hooves. It is completely normal for a horse to be a different size in front and behind, and uneven wear can put one hoof half a size off the other three. Both Cavallo and Renegade sell single boots precisely because of this.

The two ladders reproduced here

Cavallo sizes on the weight-bearing length and uses width to confirm the choice. Renegade Classic needs both figures inside a range, and offers “K” variants with a shorter length for the same width.

Cavallo size	Hoof length (mm)	Renegade Classic	Width × length (mm)
0	102–109	00	100–107 × 120–124
1	110–117	0	107–115 × 120–124
2	118–125	1	116–120 × 127–131
3	126–133	2	121–126 × 133–137
4	134–141	2W	127–132 × 133–137
5	142–149	2WW	133–139 × 133–137
6	150–157	4WW	145–151 × 145–149

The Renegade columns are not continuous — their ladder jumps from 2WW to 4WW, and the shape options (2W, 2WW) exist to cover hooves that are wider than the standard shell for that length. That is why a hoof can sit inside the overall size range and still not match a specific shell.

Clearance and shape: what the numbers leave out

Two things sit outside the sizing table and decide whether the boot actually works.

Clearance. Renegade ask for a minimum of about 3.5 mm between the hoof and the shell, and their Viper range wants 5–10 mm to allow for growth across the trim cycle. Cavallo has already built the growth allowance into its ranges. A boot that matches the hoof exactly is a boot you will not get on next month.

Shape. A hoof that measures 125 mm square and one that is 135 mm long by 118 mm wide can land in the same size band and still want different shells. A rounder, wider hoof often suits a wider shell; a narrow, longer hoof needs the narrower option or a “K” cut. If the ratio looks unusual, that is the moment to use the maker’s free sizing service rather than order from the table alone.

Frequently asked questions

What size hoof boot does my horse need?

There is no single answer — boot sizes are brand-specific. Measure width across the widest part and length from the heel buttress to the toe (excluding the heel bulbs) after a fresh trim, then look up each brand you are considering. This page does it for Cavallo and Renegade Classic.

Should I measure before or after a trim?

After a fresh trim, on the day you order. The boot has to fit the foot as it will be for the next four to six weeks, and hooves change shape across the cycle.

Can front and hind hooves be different sizes?

Regularly, yes. Measure all four before ordering. Both Cavallo and Renegade sell individual boots so you can buy a mixed pair rather than two of the same size.

Do I include the heel bulbs in the length?

No. Measure from the heel buttress line to the toe. Including the bulbs typically adds 5–10 mm, which is enough to push you down a whole size.

Related tools and guides

Sources and method

Cavallo — Measuring and Fitting your Cavallo Hoof Boots: hoof length from the heel buttress to the toe excluding the heel bulbs, the weight-bearing length as the sizing figure, and the regular vs slim sole difference.
Renegade Hoof Boots — Classic and Viper sizing charts: width × length ranges per size, the K variants for shorter hooves, and the 3.5 mm minimum / 5–10 mm recommended clearance.

Page last reviewed 2026-10-16. Results are estimates from published formulas and are not veterinary advice.