🌾 Hay Budget Calculator
The ration is in dry matter. The hay is in bales, with water in it, and some of it is never eaten. This is the arithmetic between those two facts — which is what decides what you order.
Three corrections, all pushing the same way
A ration is quoted as a percentage of bodyweight in dry matter, and that is the right way to quote it — it is the only basis on which two feeds can be compared. But nobody buys dry matter. You buy hay, which has water in it, in bales, which vary wildly, and you put it out somewhere a proportion of it gets trodden into the floor.
Each of those three is a division rather than a subtraction, and each makes the order bigger. That is what makes them worth doing properly: they do not cancel out, they compound. A budget built from the ration alone is short in the same direction every single year, and the shortfall does not announce itself — it turns up as running out of hay earlier than expected and buying more at whatever the price is then.
The waste share deserves separate attention because it is the only one you can change. The horse needs what it needs; the hay is as dry as it is; the merchant charges what they charge. How the hay is presented — on the floor, in a rack, in a net, in a feeder — is entirely within your control, and it is the thing that decides how much of what you paid for actually gets eaten.
None of which requires trusting a number from this page. The comparison table works in ratios: the gap between two rows is exact arithmetic even if the bale weight you entered is a rough guess. That gap is what a better feeder has to beat.
❓ Frequently Asked Questions
Why can't I just use the feed ration calculator and the hay cost calculator together?
Because they speak different units and nothing joins them. The ration calculator returns kilograms of dry matter — feed with the water taken out, which is the only basis on which a ration means anything. The hay cost calculator asks for bales per day. Between those two figures sit three things: the water in the hay, the weight of one of your bales, and the share that gets trampled rather than eaten. None of them appears on either page, so the bales-per-day figure ends up being guessed, and it is the one number in the chain nobody actually knows.
Why divide by the dry matter instead of subtracting the moisture?
Because you need a fixed amount of dry matter, and the water comes along with it. If a horse needs 10 kg of dry matter and your hay is 88% dry matter, you need 10 divided by 0.88, which is about 11.4 kg of hay — not 10 minus 12%, which would be 8.8 kg and leaves the horse short. The same logic applies to waste: if a fifth of what you put out is never eaten, you need to put out the eaten amount divided by four fifths, not the eaten amount plus a fifth. Both mistakes understate the order, and they understate it in the same direction, so they compound.
Why is there no default bale weight?
Because a bale is not a unit of measurement. Small squares and large rounds differ by more than an order of magnitude, and two small squares off the same field can differ by enough to change your order. Any number typed here would be wrong for most people while looking authoritative, and it is the single input that most changes the answer. Weigh three of yours on a bathroom scale and average them. It takes five minutes, it is the highest-value five minutes on this page, and after it every figure here is true for your yard rather than for nobody's.
Is the waste figure really worth worrying about?
It is the only number on the page that is also a decision. The ration is set by the horse, the moisture is set by the hay, and the price is set by the market — you cannot argue with any of them. How the hay is presented is entirely yours, and it is what decides how much ends up on the floor. The table shows the annual cost at a range of waste shares precisely so you can hold a feeder's price against the gap between two rows, rather than taking anyone's word for what a feeder saves.
Where do the waste percentages in the table come from?
They are a range to read across, not a claim about your yard. The absolute cost of any row is only as good as the bale weight and price you entered, but the ratio between two rows is exact arithmetic and does not depend on either being right. That is deliberate: the useful output is what halving the waste is worth, which is a comparison, rather than a figure asserting what your waste currently is. Only you can measure that, and watching how much hay ends up bedded into the floor for a week will tell you more than any published number.
Does this replace advice from my vet or nutritionist?
No. Everything here starts from a forage percentage you have already chosen, and choosing it is the veterinary and nutritional question — it depends on workload, condition, age, and whether the horse has any of several conditions that change feeding entirely. This page does arithmetic on a decision already made. If the forage share itself is what you are unsure about, that is a conversation with a professional, not a calculator, and the comparison table will tell you what each answer costs once you have it.