30K total tax at 28% --> AGI = 100K --> 100K deduction will be a lot, so AMT will not be triggered.
AMT is another system to estimate tax, so it is usually compared to normal tax. People will say "I am hit by AMT" by meaning "my AMT is higher than my normal tax".
If one say: I need to pay extra 3K because of AMT, that makes sense.
If 30K is AMT over normal tax, AGI would be close to 400K, 'cause 500K+ won't be hit by AMT either. (see so many other posts before).
Really not sure if 30K extra because of AMT is reasonable, so here are some estimation: 300K with 2 W2, 4 people household.
250K-4*3700-2*16500-25000 = 177.2K assume 25K deduction left. at 28% the tax is 4.9K.
300K-4*3700-2*16500-20000 = 232.2K assume 20K deduction left. at 28% the tax is 6.5K.
400K-4*3700-2*16500-15000 = 337.2K assume 15K deduction left. at 28% the tax is 9.4K.
500K-4*3700-2*16500-10000 = 422.2K assume 10K deduction left. at 28% the tax is 124K.
seems 500K is about right that withhold is missed by 25%. That is a big mistake though.
