How Savery's Savings Number Works
Savery shows you a dollar figure: the value of the food you didn't throw away. That number is most of the reason the app exists, so it's worth explaining how it gets produced, and where its limits are.
Where the dates come from
Every item that comes off a receipt is matched to a food category, and each category carries a shelf life range drawn from the USDA's FoodKeeper database, a public reference maintained by the USDA Food Safety and Inspection Service with Cornell University and the Food Marketing Institute. It covers storage times for hundreds of foods across pantry, refrigerator, and freezer.
FoodKeeper gives ranges, not single dates. Ground beef in the fridge is good for a window, not a moment. When Savery collapses a range into a date, it takes the early end of that range on purpose. The reasoning is asymmetric. A reminder that arrives a day early costs you nothing; you eat the spinach on Tuesday instead of Wednesday. A reminder that arrives a day late costs you the spinach.
FoodKeeper is thin on fresh produce, which is a problem, because produce is where most of the money leaks. Those dates are supplemented with published research from the UC Davis Postharvest Technology Center, which studies how specific fruits and vegetables behave after harvest under different storage conditions.
Storage matters more than the calendar for a lot of this. A tomato on the counter and a tomato in the refrigerator are on different clocks, so a change in storage changes the speed of the clock rather than restarting the countdown.
Where the dollars come from
Every item on your receipt has a price you actually paid. That price is the raw material, and it's why receipt capture is the only way into the app. Savery takes the price and scales it by the consumer level loss rate the USDA publishes for that food category, from the Economic Research Service's Loss-Adjusted Food Availability data series. That series estimates what share of food is lost at the consumer level, category by category. Some categories are much worse than others. Leafy greens are not bread.
So an item's contribution to your savings figure is the price on the receipt scaled by how likely food of that type is to get thrown out. Use a bag of spinach before it turns and you're credited with the portion of what you paid that statistically would have ended up in the bin, not the entire purchase price.
Why dollars and not pounds
Most food waste research is measured by weight, because weight is what's practical to measure at scale. Weight is the wrong unit for a savings figure. A pound of ground beef and a pound of iceberg lettuce weigh the same and cost very different amounts. Weighted by pounds, produce dominates the total and the number stops tracking the thing you care about. Savery weights everything by dollars, so the figure moves with what you actually spent.
What this number is not
It's an estimate, and a deliberately cautious one. It is not a measurement of your household. It's your prices run against national averages for how often food of that type gets discarded, with dates rounded toward acting sooner. Your real waste differs from the average, probably by a lot, in one direction or the other, and we have no way of knowing which.
It also isn't a food safety judgment. FoodKeeper dates are quality and storage guidance, not a guarantee that something is safe or unsafe to eat. Trust your own judgment on the item in your hand. Savery tells you when to pay attention; it doesn't certify anything.
The number is built to be defensible rather than impressive. If we wanted a bigger one, we could credit the full purchase price of every item you used before its date, and the figure would be meaningless. Every rounding decision above runs the same direction, toward claiming less.