I was trying to figure this out a year ago, I found an article from 2014 that laid out the rough rule for evaluating AMT. It's a function of both taxable income under the regular system (i.e. AGI minus deductions and exemptions), and the amount of deductions you take, including personal deductions (but not including mortgage interest and charitable deductions, which are still deductible under AMT).
The summary is that as your income goes up, the amount of deductions required for the AMT to kick in increases.
At $50k taxable income, you'd need over $57k in deductions to get hit with the AMT.
At $200k taxable income, the number is around $30k of deductions and exemptions.
At $400k, it's only $16k of deductions/exemptions which is less than a married couple's personal exemptions and the standard deduction.
You'll pay a marginal rate of anywhere from 25% to 32.5% on any amount of deductions + exemptions above the kick-in amount.
Here is the link:
https://www.kitces.com/blog/evaluating-exposure-to-the-alternative-minimum-tax-and-strategies-to-reduce-the-amt-bite/Of course, the "good news" is this may be moot. The just released GOP tax "reform" framework eliminates the AMT and the state and local tax deductions that trigger it.