Time is running out to ship your gifts and order them for guaranteed delivery by Christmas Eve.

Monday is the deadline for FedEx's ground and home delivery, while Tuesday is deadline for UPS's most affordable delivery option, UPS 3 Day Select. The deadline for  free shipping on Amazon orders also is Tuesday.

The Postal Service's deadline for its priority and first class mail is more generous and packages need to be mailed out on Thursday.

In a    statement, USPS said Dec. 17 was anticipated to be its "busiest day online with more than 8 million consumers predicted to visit usps.com for help shipping that special holiday gift."

The week through Dec. 23 also is expected to be the service's busiest week for mailing, shipping and delivery. It expects to process and deliver nearly 3 billion pieces of First-Class Mail, including greeting cards.

All three major carriers, Amazon and many retailers also offer last-minute options.

To help them make sure your gifts get to their final destination on time – and save a little money – there are a few key shipping deadlines to pay attention to.

These are the three major carriers' recommended send-by dates for expected delivery by Dec. 25:

U.S. Postal Service

Dec. 18: APO/FPO/DPO (except ZIP Code 093) through Priority Mail Express

Dec. 20: First Class

Dec. 20: Priority Mail

Dec. 22: Priority Mail Express

FedEx

Find rates and transit times at                 www.fedex.com.             

Dec. 17: Ground and home delivery

Dec. 19: Express Saver

Dec. 20: Two-day options

Dec. 21: Overnight options

Dec. 25: FedEx SameDay, FedEx SameDay City Direct and City Priority

United Parcel Service

Calculate time and cost at                 www.ups.com.             

Dec. 18: UPS 3 Day Select

Dec. 20: 2nd Day Air

Dec. 21: Next Day Air

Dec. 22: UPS On-Call Pickup for UPS Next Day Air

Kelly Tyko is a consumer columnist and retail reporter for Treasure Coast Newspapers and   TCPalm.com, part of the USA TODAY NETWORK. Read her Bargainista tips at   TCPalm.com/Bargainista, follow her on Twitter    @KellyTyko and email her at  kelly.tyko@tcpalm.com.