Taxes are tough. The math behind them, however, isn't. It shouldn't be so difficult to get a vague idea of whether you'll owe AMT in advance of tax day.
As I couldn't find a satisfactory AMT calculator online (with reliable outputs), I've endevoured to build one. Issues, PRs, feedback are all encouraged.
Modify the values in tax_details.json to fit your tax situation:
{
"income": 222222, // Income + all taxable benefits (cafateria food, etc). Do not include RSUs here.
"iso_share_gains": 44444, // The `value` of RSUs vested (ignore the withholding taxes and state their full value)
"rsu_income": 33333, // The net gains of ISO shares
"pension": 11111, // The quantity you put into a 401k this fiscal year (do not include employer contributions)
"verbose": true // Whether to print details of the calculations
}
And then run the script
$ ruby run.rb
*** AMT Calculator 0.0.1 ***
Note: this is a script which seeks only to provide insight into broad tax trends.
The output will be unreliable and does not provide any legal or tax advice.
Consult a tax lawyer to discuss your situtation.
---- TAX INPUTS ----
Income: $222222
ISO Gains: $44444
RSU Income: $33333
401K: $11111
---- FEDERAL TAX ----
Taxable income after standard deduction: $232444
Adding $952.5 to federal taxes from 0..9525 tax bracket at 10.0 %
Adding $3500.8799999999997 to federal taxes from 9526..38700 tax bracket at 12.0 %
Adding $9635.78 to federal taxes from 38701..82500 tax bracket at 22.0 %
Adding $17999.76 to federal taxes from 82501..157500 tax bracket at 24.0 %
Adding $13599.68 to federal taxes from 157501..200000 tax bracket at 32.0 %
Adding $11355.05 to federal taxes from 200001..500000 tax bracket at 35.0 %
No additional taxes in the 500001..Infinity tax bracket at 37.0 %
= $57043.64
---- AMT ----
AMT adjusted income: $288888
Adjusted income retains full exemption. Taxed at 26% up to $191500 and at 28% beyond
= $58780.64
---- OUTCOME ---
You owe AMT this year (which is $1736.99 greater than the standard tax)
- Uses the standard deduction for federal taxes, not itemized deductions
- Only handles
singlefiling status - Only works for updated 2018 tax laws
- Does not pretty print currency or handle their precision correctly
- Messy code base violates single responsibility principle in several places
- Does the Standard Deduction subtract from the top tax brackets or the bottom? (assumed bottom in this script)
This script will, at best, provide insight into broad tax trends. It is overwhelmingly likely to contain bugs, over simplistic approximations, and misinterpretations of tax laws. Consult a tax lawyer to discuss your tax sitation.
MIT