If you're trying to get packages sent out to loved ones before Dec. 25, today would be a good day to finish the job.

The United States Postal Service advises that customers using regular postage should mail their holiday cards and packages by today, Dec. 20, for arrival by Dec. 25.

If you use the Postal Service's Priority Mail option, you can send your holiday mail to anywhere in the U.S. on Dec. 21. Flat rates for this option start at $5.15. You can save six percent by completing your order online.

If you use the Express Mail option, you can send holiday mail anywhere on Dec. 22 to arrive by Dec. 25. This is the most expensive U.S. Postal Service shipping option for domestic orders. Flat rates for this option start at $18.95.

Don't delay—send your holiday mail today!