How to estimate W4 using annual income only with irregular third job

[JohnduBois]

Good morning, everyone.

I have a bit of a weird W4 situation, and I'm trying to figure out how to make it work in the IRS's W4 estimator.

Between my wife and I, we have three jobs:

1. She works a job with a regular salary (yay, this one's easy for the W4 estimator)

2. I just started a new school job where my salary is prorated for the rest of the school year, but will be at the full salary in the fall. I think the estimator can handle this as well, as long as I get the correct expected income for the whole year in there.

3. I have a third job that I work during school breaks. I can roughly estimate my pay for the year, but the estimator's asking for whether I get paid weekly, biweekly, etc, which I can't really answer because some weeks I'll get paid a few thousand dollars, and some weeks (or months) I'll make nothing.

I'm trying to figure out how to fudge these numbers so that I gat a W4 that makes sense, because last year I definitely failed at this and we overpaid our taxes by a five-figure amount, something I'd like to avoid again this year.

Can anyone provide any advice?

[Vanessa A]

For your third job if you know roughly what you will make for the year, then you can select that you get paid monthly or weekly and then divide your expected yearly wages for this job by either 12 or 52, depending on if you choose monthly or weekly.

You can also re-evaluate mid year.  If you seem to be on track to make what you think you will keep your W-4 the same.  If you  end up  making less or more, then you can still change your W-4 at that point.  There is no rule that says you can only do a new W-4 once a year. You can make changes whenever you see you will have a deviation from what you had on your last W-4. 

[JohnduBois]

What would I do for the third job when it asks me about my last pay stub? Or does the actual amount of payment/taxes matter less than the percent of income paid in taxes?

[MonikaK1]

If the income from the third job will be erratic, and is not full-time, you could select in the estimator that you currently hold the job, but only for part of the year, and figure the total amount you expect to earn.

You could also choose the TurboTax W-4 Estimator if you find it easier to use.

Remember that these tools are just that - estimating tools. You can always adjust your withholding during the year if something changes.

See also this TurboTax tips article for more information on this topic.

@JohnduBois