My husband is possibly getting a large bonus this year, maybe beginning of next (so this may be for 2018 taxes) but what is the tax implication of receiving a sum of money all at once?

[skogman2]

Should I expect to set aside a certain percent to pay for the extra taxes? I just don't know what percentage that would be.

[SweetieJean]

The 2018 Federal tax law is likely to change, so keep watching the news. And remember state and local taxes as well.

[TomYoung · Accepted solution]

The tax implication of getting a bonus is pretty much exactly the same as getting a raise; your income taxes will go up based on your marginal income tax rate.  Your taxes may go up more than you expect for various reasons: you move into a higher tax bracket, (that's pretty easy to understand), or your higher income or results in some of the numerous phase-outs, phase-ins, surtaxes and other "gotcha's" that litter the US Income Tax Code, (e.g., the so-called Pease limit on itemized deductions).

Bonuses are simply "compensation" and about the only thing that makes a bonus different than a regular paycheck is that the withholding is typically calculated at a flat "supplemental rate" of 25%.  Most states tax bonuses in a similar fashion.  Without knowing your personal details I can't say if the supplemental rate will completely cover your additional tax liability or result in a refund or a large amount owed. 

Tom Young