This is not exactly according to Doyle but my process (rule of thumb) usually works. The first things to get out of the way:
Other than change in income, are there any other differences? Dependents, 401K contributions, other withholdings i.e. childcare benefits for instance.
For the first half of your year take the fed withholding (box 2) and divide it by wages (box 1).
1) If your income was less than $40K and you are single adjust or increase your withholding to 12%
If you are MFJ make sure the first $80K withholding was 12% (or more)
2) If your income was less than $90K and you are single adjust or increase your withholding to 12% for the income for the first $40K and for your income between $40K and $90K adjust or increase your withholding to 22%
If your income was less than $180K and you are MFJ make sure the first $80K withholding was 12% (or more) and for your income between $80K and $180K adjust or increase your withholding to 22%
3) For this step take the first two and add a third:
If your income was less than $170K and you are single, for your income between $84K and $170K adjust or increase your withholding 24%
If your income was less than $340K and you are MFJ, for your income between $170K and $340K adjust or increase your withholding 24%.
If you are earning more than $100K you should really at least consult with a tax professional to determine all/any of the exceptions to my 'rule' such as capital gains (usually maxes out at 15%), work related deductions, and of course, dependents. Using box 1 as your calculation basis is reliable.
