My general rule on this is to send the IRS at least 20% of the as-of-yet untaxed earnings. In your case, that would be 20% of your gain. To determine more accurately what you taxable gain is, take what you paid for the property and subtract from that the total depreciation you have taken on the rental since you owned it. That gives you your adjusted cost basis.
Now subtract that cost basis from your sales price, and that will give you (roughly) your taxable gain. Send the IRS 20% of that gain and come tax time, you'll be fine.
You can pay that 20% online if you like, directly to the IRS at <a rel="nofollow" target="_blank" href="
http://www.irs.gov/directpay">http://www.irs.gov/directpay</a>. Make sure you print your receipt and file it with your 2017 tax paperwork so you'll have it at tax prep time. Also, if your state taxes personal income you should also go ahead and send your state 20% of your gain also.
In the end when you actually file the tax return, you'll probably end up getting some that refunded to you. But if not and you end up owing, so long as what you owe is less than 10% of your total tax liability, no underpayment penalties will be assessed.
