For my money, the best thing is the calorie calculator tool. Unlike the Precision Nutrition tool (which estimates safe weight loss), this one will give you the numbers needed for any goal no matter how ridiculous (although it might warn you it's ridiculous).
What's great is that you can estimate calories needed for weight, gain, too. If I want to put on 10 pounds in 30 days, I need to take in another 1200 kcals a day according to the calculator, over a maintenance level of 3800 kcals. Sweet! Costco, here I come!