Two meanings of “cost per day”
| Meaning | Question it answers | Typical mistake |
|---|---|---|
| Eaten cost | If I feed K kcal/day from this SKU, what is food+fees per calendar day? | Ignoring leftover inventory after a 30-day buy |
| Cash when the box ships | What hits my card on each order date? | Spreading a huge first discount across all future months |
This hub tries to show both. A low first box does not equal the long-run day cost.
Required inputs (no silent fill-ins)
- Your daily calorie target
K(we do not prescribe calories from body weight). - Same-SKU energy
Eand net weightWfrom the label or equivalent official page. - Food price
P, shipping/cold-chainS, taxT, optional first-order food discountD. - Whether the product is a complete meal vs supplemental/topper (see labels).
If kcal or shipping is unknown, leave it unknown. Open the daily cost calculator — check “unknown” rather than guessing. Volunteers can send redacted label kcal/net weight or bill totals via Contribute; we merge those with official data under the hybrid gap method—we do not invent figures.
First-order vs recurring
Many fresh brands discount the first Subscribe & Save box and charge closer to list afterward. Always place first-order day cost next to recurring day cost. Food discounts usually do not erase shipping or tax; free-shipping thresholds may be calculated after discounts and before tax—read the brand policy (example workflow on the JustFoodForDogs cost module).
Arithmetic demo (not a brand quote)
From the site plan’s pure math assumptions: W=4000 g, E=1.6 kcal/g (6400 kcal/box), P=$80, S=$10, T=$0, D=$16 (20% off food only).
| K (kcal/day) | g/day | Days/box | Recurring $/day | First-order $/day |
|---|---|---|---|---|
| 400 | 250 | 16 | $5.63 | $4.63 |
| 800 | 500 | 8 | $11.25 | $9.25 |
| 1200 | 750 | ~5.33 | $16.88 | $13.88 |
These calories are not size-class prescriptions. At 800 kcal with four separately shipped boxes in 30 days, cash outlay and leftover inventory differ from “eaten” cost—see methodology.
Common traps
- Mixing frozen and shelf-stable SKUs into one average.
- Using a topper’s cheap “per day” as if it replaced a complete diet.
- Assuming Alaska/Hawaii/PO Box shipping matches contiguous US.
- Treating pause as cancel when modeling next charges.
Next: calculator · shipping checklist · JFFD review · Contribute a price/label report.