Monday marks the beginning of the busiest week of the year for the US Postal Service, with around 200 million packages expected to be delivered from now until Sunday.

If you’re shopping online for Christmas, Monday (Dec. 17) is the last day for FedEx Ground and Home Delivery options to arrive before December 25.

Tuesday (Dec. 18) will be the last day for free shipping through Amazon. Free two-day Prime shipping for Christmas deliveries continues through Saturday (Dec. 22).

Thursday (Dec. 20) is the deadline for First Class packages and Priority Mail through the Post Office. Thursday is also the last day for UPS 2nd Day Air.

UPS, FedEx and the US Postal Service will have other shipping options as Christmas gets closer, but expect to pay higher shipping fees as each day goes by.

For the FedEx holiday shipping deadlines, click here.

For the UPS holiday shipping deadlines, click here.

For the US Postal Service holiday shipping deadlines, click here.