Horse weight calculator
Without a weighbridge, the most reliable field estimate of a horse's bodyweight comes from heart girth and body length using the Carroll & Huntington formula. Measure both in centimetres and this calculator returns an estimated weight in kilograms and pounds — the number you need for correct wormer, feed and medication dosing.
The calculator itself is interactive and loads with the page. It is free, needs no signup, and nothing you enter is stored.