Fill in all the factors that influence your decision in the top header row. Examples might be "price" and "reliability" if you're trying to decide between cars, or "prettiness" and "ease of spelling" if you're trying to decide between baby names.
"Weight" refers to the relative importance of that factor. Weight can be any number. If you fill in 1 under "price" and 5 under "reliability," then reliability scores will be given 5 times more weight than price in the final score tally.
Fill in your "contenders," the candidates you're trying to decide between, along the leftmost column.
In scores, higher is always better. (This is counterintuitive for items like "price" where lower is better for you.) Scores can be any number, but it may help you to decide on a predetermined range, such as 1-5, with 5 being the best.
Letter grades go from A+ down to F-. Grading is curved, so there is always at least one A+. Grading is less strict than in school; you must have a grade of less than 17/100 to get an F.
After hitting "Calculate," you can copy the URL to share your decision matrix with your friends.