How much hay does a horse need per day?

The basic rule

As a starting point, horses need roughly 1.5–2.5% of their bodyweight in forage per day (hay, haylage and/or grazing combined), on a dry matter basis. Where in that range depends on workload, condition and how much grazing they already get.

• Maintenance / good doer: around 1.5% of bodyweight
• Average, light work: around 2% of bodyweight
• Hard-working or poor doer: around 2.5% of bodyweight

So a 500kg horse at maintenance needs roughly 7.5kg of forage a day; a hard-working 500kg horse might need closer to 12.5kg.

Quick calculator

This is a starting estimate, not veterinary advice — always adjust for your own horse's condition and check with your vet or nutritionist for anything beyond general guidance.

Don't forget grazing

If your horse has decent grazing access, that counts toward the total — you're not necessarily feeding the full amount as hay on top. A horse turned out on good grass for 8+ hours a day may need very little supplementary hay in summer, while a horse on a bare winter paddock needs it made up almost entirely from hay or haylage.

Haylage vs hay

Haylage has a higher moisture content than hay, so you generally need to feed more of it by weight to supply the same amount of dry matter — roughly 1.3–1.5x the weight of hay, depending on how wet the bale is.

Keeping track of this across several horses, plus rechecking it every time workload or grazing changes, is exactly the kind of thing that's easy to lose track of. MyGroom's hay & haylage calculator does this per-horse automatically, factoring in grazing hours and grass quality, and tracks what's left in the barn so you know when you're running low.