Here at All Day Organics, we love using math to save money. If you're handy with a calculator (or your phone), you can save all kinds of money by just choosing another size package of the products you buy. Check out our sweet infographic that will tell you how to compare the UNIT COST of products, not just price stickers. Using our Mr. Mucha-Stash Calcium Magnesium and Iron supplement as an example, we walk through finding the best deal for your budget and your garden. Use the lessons of the Big Money Mustache to get more for your hard-earned dollars. 

So, how do you apply this to other things you buy, like sausages and toboggans? Most grocery stores list the unit price right on the price tag, like this.

You don't even  need to use your calculator. Choose the size that has the best unit price, and that you can reasonably use before it goes bad.

What if the store doesn't tell you the unit price? Well, let the mustache do the work:

For liquid products, look at the volume listed on the package. Most are sold in fluid ounces (fl oz), gallons (gal), milliliters (mL) or liters (L). For dry products, the units are usually grams (g), pounds (lb), or ounces (oz). Confusingly, liquid (fluid) ounces and dry ounces are not the same! A fluid ounce measures volume, and there are 128 fluid ounces in a gallon. Dry ounces measure weight (and mass, if you're on Earth). There are 16 dry ounces in a pound (lb).

It doesn't matter what unit you choose as long as it's the same one for all the products. Things get more complicated when you are comparing unit prices between different brands. If they list different units, you may have to do some conversions. Here is a simple list of the common ones:

1 gallon = 128 fl ounces

1 gallon = 4 quarts = 8 pints

1 gallon = 3.78 L = 3780 mL

1 liter (L) = 1000mL

1 pound (lb) = 16 ounces

1 pound (lb) = 454 grams

1 kilogram (kg) = 1000 g = 2.2 lb