This master mix makes enough for seven full 9×13 cakes, with about 1–2 cups left over, which is perfect for a small batch of cupcakes or topping off another cake. For labels or printables, the most accurate and safe wording is simply: Makes 7 (9×13-inch) cakes. Because the mix includes shortening, the shelf life depends on how it’s stored—when kept in a standard pantry it’s reliable for 3–4 months, but if stored in a cool, airtight container, you can comfortably extend that a bit longer while maintaining quality.