Leftover Repurpose Portions Calculator Formula

Understand the math behind the leftover repurpose portions calculator. Each variable explained with a worked example.

Use the Leftover Repurpose Portions Calculator

Formulas Used

Meals from Protein

meals_from_protein = floor(leftover_protein_oz / target_protein_oz)

Meals from Grain

meals_from_grain = floor(leftover_grain_cups / target_grain_cups)

Maximum Complete Meals

limiting_factor = floor(leftover_protein_oz / target_protein_oz) < floor(leftover_grain_cups / target_grain_cups) ? floor(leftover_protein_oz / target_protein_oz) : floor(leftover_grain_cups / target_grain_cups)

Veggies per Repurposed Meal

veggie_per_meal = (floor(leftover_protein_oz / target_protein_oz) < floor(leftover_grain_cups / target_grain_cups) ? floor(leftover_protein_oz / target_protein_oz) : floor(leftover_grain_cups / target_grain_cups)) > 0 ? round(leftover_veggie_cups / (floor(leftover_protein_oz / target_protein_oz) < floor(leftover_grain_cups / target_grain_cups) ? floor(leftover_protein_oz / target_protein_oz) : floor(leftover_grain_cups / target_grain_cups)) * 10) / 10 : 0

Variables

VariableDescriptionDefault
leftover_protein_ozLeftover Protein(oz)16
leftover_grain_cupsLeftover Grain/Starch(cups)3
leftover_veggie_cupsLeftover Vegetables(cups)2
target_protein_ozProtein per New Meal(oz)4
target_grain_cupsGrain per New Meal(cups)0.75

How It Works

How to Plan Meals from Leftovers

Formula

Meals from Protein = floor(Leftover oz / Target oz per meal)

Meals from Grain = floor(Leftover cups / Target cups per meal)

Complete Meals = min(Meals from Protein, Meals from Grain)

The limiting ingredient determines how many complete meals you can assemble. Any excess of one component can be used in simpler dishes (grain bowls, salads, wraps).

Repurposing Ideas

  • Leftover chicken becomes chicken salad, quesadillas, fried rice, or soup
  • Leftover rice becomes fried rice, rice bowls, stuffed peppers, or rice pudding
  • Leftover vegetables become frittatas, stir-fries, wraps, or pasta toss-ins

    • Worked Example

    16 oz leftover chicken, 3 cups rice, 2 cups mixed veggies.

    leftover_protein_oz = 16leftover_grain_cups = 3leftover_veggie_cups = 2target_protein_oz = 4target_grain_cups = 0.75
    1. 01Meals from protein = floor(16 / 4) = 4
    2. 02Meals from grain = floor(3 / 0.75) = 4
    3. 03Complete meals = min(4, 4) = 4 meals
    4. 04Veggies per meal = 2 / 4 = 0.5 cups each
    5. 05You can make 4 chicken rice bowls with veggies.

    Frequently Asked Questions

    How long are leftovers safe to eat?

    Most cooked leftovers are safe for 3-4 days in the refrigerator at 40°F or below. If you cannot eat them within that window, freeze them for up to 3 months. Always reheat to 165°F internal temperature.

    What are the best meals to make from leftovers?

    Fried rice, grain bowls, wraps/burritos, frittatas, soups, and casseroles are all excellent for using up various leftovers. These flexible formats accommodate almost any combination of protein, grain, and vegetables.

    How do I reduce food waste?

    Plan your weekly meals before shopping. Cook only what you will eat in 3-4 days (freeze the rest). Store leftovers in clear containers so you can see what needs to be used. Designate one day per week as a "use it up" day.

    Ready to run the numbers?

    Open Leftover Repurpose Portions Calculator