If you’ve been putting off upgrading your Windows 7 or 8 operating system to Windows 10 — even after all that nagging, prompting, and pestering from Microsoft — today is decision day: either upgrade for free before the end of the day, or you’ll have to pay if you upgrade later.

Microsoft has been warning folks for months that the deadline was nigh, telling customers that the chance to upgrade for free would end on July 29.

Despite that deadline, however, you have a little bit of wiggle room: “Windows 10 upgrades must be fully completed by 11:59 p.m. UTC-10 on July 29, 2016,” a Microsoft spokeswoman confirmed to Consumerist.

That translates to July 30 at 5:59 a.m. EDT for those on the eastern seaboard, and 2:59 a.m. PDT on July 30 for those living on the West coast. If you want to be safe, probably aim to do it tonight, and not in the small hours of the morning.

If you don’t get your upgrade downloaded by the deadline, you’ll have to pay $120, while Windows 10 Pro will cost a cool $200.

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