How much does a US Army Major make?

$3000 to $5000 a month depending on how many years the Major has been in.

This answer is a little bit / actually a lot off. I am a 2LT, or Second Lieutenant in the USAF, but I am an O1E, which means I am prior enlisted. My salary is only part of my pay, I also get housing allowance and money for food each month (both are tax free). I am at Eglin, this matters for the amount of housing allowance you will receive, and my bring home pay is 2520 every 2 weeks. This is more than the previous estimate for the O4 and I am only an O1 with 10 years in service. If I were an O4 (today) with approximately 18 years in service, I would be making around 110K per year. This comes out to about 9200 per month.