Storage, leftovers and shelf life
The food storage and shelf-life calculator and the leftover reheating calculator draw on USDA guidance: shelf-life figures reflect the USDA FoodKeeper data and the Food Safety and Inspection Service, and leftovers are reheated to 165°F. These are general guides. How long a food really keeps depends on how it was stored and what condition it was in when you bought it, so when you are unsure, throw it out.
Planning and portioning
The grocery list quantity scaler and the meal prep portioning calculator multiply a recipe by the number of people or meals you are cooking for, which is the same proportional scaling used throughout the site. The unit price comparison calculator divides price by quantity so two package sizes can be compared on the same footing.
Cost and nutrition
The recipe cost calculator uses the standard unit-cost method: package cost divided by package quantity, multiplied by the amount you use. The recipe nutrition calculator is a simple arithmetic estimate, total divided by servings. It is not a certified nutrition-facts label, so for verified values look up each ingredient in a database such as USDA FoodData Central. The disclaimer covers the limits.
Putting the tools together
These tools work well in sequence: scale the grocery list for the number of people, divide the cooking into meal prep portions, check how long each item keeps and reheat leftovers to a safe temperature. Each page shows its method, and the how we calculate page explains the sources.