Web app · Lifestyle
HayDays
Will the hay last until the grass comes back? Here is the honest date
Build your herd once, count what is in the barn, and HayDays divides pounds on hand by your true daily burn — waste included — to plot the run-out date against pasture return, then tells you exactly how many bales to buy. Free, offline, no account.
Stored in your browser only. Nothing you do in the web version is sent to our servers. Clear your browser data and it's gone — so export a backup from the in-app menu if you want to keep it.
In your browser
What you can do in HayDays on the web
The run-out date, not a bale count
Pounds on hand ÷ herd burn rate = days of hay, drawn on a season timeline against your pasture-return date with a green, amber or red verdict and a days-of-margin number.
A herd model that includes waste
Each horse, pony, goat, sheep or cow carries its bodyweight, the extension-standard intake percent (2% horses, 3% goats and sheep, 2.5% cattle) and a waste percent for what gets trampled, soaked and refused.
Hay by the lot, fed down as you go
Log each lot with bale count, bale weight, price and supplier; knock bales off with a stepper as you feed them and every forecast moves with you.
The buy planner
Pick a feed-through date and a bale size and HayDays gives the exact number of bales, the pounds behind it, and what the order costs at your best recorded rate.
Price book in dollars per ton
50 lb squares at $8.50 and 4x5 rounds at $68 are the same number once you normalise: price ÷ bale weight × 2000. Every quote ranked cheapest first, per supplier.
The math, line by line
Every animal's intake, every lot's pounds, then the division — so you can check the forecast against your own pencil math before you spend a thousand dollars.
Screens
Every screen, rebuilt for the browser
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1
Forecast
Run-out date, verdict, season timeline against pasture return, burn rate, pounds on hand and days of margin.
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2
The math
Per-animal burn rate, per-lot pounds, the division step by step, and the pasture-return and safety-margin controls.
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3
Herd
Every animal with its lb/day, the herd total, and the share of the burn by species.
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4
Animal
Species, bodyweight, intake percent and waste percent, with a live lb/day readout.
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5
Hay
Every lot with pounds, dollars per ton, days of feed and a bale stepper to feed it down.
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6
Hay lot
One lot's pounds, cost, normalised price per ton, supplier and notes.
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7
Buy planner
Bales needed for your feed-through date, estimated cost at your best rate, and the same order in other bale sizes.
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8
Price book
Every quote normalised to dollars per ton, ranked cheapest first, filtered by supplier.
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9
Settings
Pasture return, safety margin, default bale weight and waste, CSV and JSON export, sample data and erase.
Try it with sample data: Loads a five-head backyard barn — two horses, a pony and two goats — with four hay lots (96 squares in the loft, an overflow shed, six 4x5 rounds and goat hay), four suppliers and five quotes from $170 to $462 a ton, so the forecast, buy planner and price book are all live. You can start fresh at any time.
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Questions
Is the web version of HayDays free?+
Yes. Sign in with a free All Things AI account and use every screen — no subscription, no in-app purchases.
Where is my data stored?+
Only in this browser's local storage. Nothing you enter is sent to our servers, so we can't see it, back it up, or restore it. Clearing site data, a private window, or another device starts empty. Export a backup from the in-app menu to keep it.
Do I need an account?+
You can read about the app without one, but you must sign in to open it. Sign-in is free and takes a few seconds with Google.
How is the web version different from the HayDays iPhone app?+
No notifications on the web — HayDays re-forecasts every time you open the page, but it cannot warn you in February the way the iPhone app can. There is no photo or barcode capture for a hay receipt; quotes and lots are typed in. Everything is saved in this browser only — it does not sync to the barn phone, and clearing site data erases it. Export a JSON backup before winter.