Changing allowances doesn’t change the overall tax you owe, it just changes the timing of when you pay. For every one allowance you add to your W-4, you will get about $20 per week or $80 per month in take home pay, and a $1000 smaller tax refund.
This is no problem unless you end up being under-withheld and owing tax at the end of the year. If you owe more than $1000 you will also be charged a penalty and interest for late or under-payment.
