The small bag was $24.99. I bought it on a Friday night in May at Target, still in my scrubs top, because the bin at home had maybe two days of food left and Hank's next autoship box was a week out. I didn't think much about it until I typed it into the pet tab and saw it sitting two rows below the big bag, looking very expensive for its size.
Here's how we got there. During Hank's crate rest last winter he gained four pounds, so his portions got cut, and a 34-pound bag that normally lasts about 38 days stretched well past that. I kept pushing the autoship date back. Then spring came, he started walking again, his portions went back up, and I never pulled the shipments forward. We ran short twice in May: once the 6-pound bag at Target, once an 18-pound bag at Fleet Farm.
The per-pound math
All three sizes are the same food, Purina Pro Plan Large Breed Adult. List prices this July:
- 6-pound bag: $24.99, or $4.17 a pound
- 18-pound bag: $56.99, or $3.17 a pound
- 34-pound bag: $79.99, or $2.35 a pound
- 34-pound bag on Chewy autoship, 5 percent off: $75.99, or about $2.24 a pound
Hank eats a little under nine-tenths of a pound a day, roughly 27 pounds a month. Feed him entirely from 6-pound bags and that's about $113 a month. From 18-pound bags, about $86. From the big bag on autoship, about $61. Same dog, same food, and more than $600 a year between the smallest bag and the biggest.
Our two stopgap bags in May cost about $28 more than the same amount of food would have out of a big autoship bag. Not a disaster. Just the price of not paying attention, which is a line I'd like to keep off the spreadsheet.
When the bigger bag isn't actually cheaper
The per-pound number only counts if the food gets eaten while it's still good. Once a bag is open, air gets at the fats in the kibble and it slowly goes stale, then rancid. The best-by date printed on the bag is for an unopened bag. Our vet's rule of thumb is to finish an opened bag within about six weeks, and Hank does it in a little over five. If he were a 20-pound dog, a 34-pound bag would sit open for months and the "cheap" bag would be the wasteful one.
That's exactly why Mabel's math runs the other way. Since April she eats mostly wet food and only a small scoop of dry a day, so we buy her dry food in a small bag even though the per-pound price is worse. A cat eating a few tablespoons a day isn't getting through a big bag before it turns.
Storage matters too. Hank's bag goes into an airtight bin in the mudroom, still inside its original bag. The bag keeps the lot number and best-by date with the food in case of a recall, and its lining does a better job than bare plastic. Between bags, the bin gets washed and dried, because the thin film of oil on the inside goes stale on its own and you'd be pouring fresh food on top of it.
And there's cash flow. Seventy-six dollars at once is not the same as twenty-five dollars this week, and I've stood on the other side of a counter long enough to know the cheapest-per-pound option isn't always the one that fits the month. No judgment from me on small bags.
What we changed
- The autoship now runs every five weeks, a few days ahead of when the bin actually empties.
- Three days before each shipment, a reminder on my phone tells me to look in the bin. If it's more than a third full, I push the order back a week.
- When Hank's portions change for any reason, the autoship changes the same day. That was the real mistake in May, not the bag size.
Hank, for the record, has no opinion about bag sizes. He has a strong opinion about 4:30 p.m., and he'd like everyone to know that it's already 4:25.
