A look at shipping deadlines for major online retailers to guarantee delivery by Christmas. All times are Eastern Standard Time.

_Amazon.com: Monday is the last full day for standard shipping, Tuesday for two-day and 7:30 p.m. Wednesday for one-day shipping. Some gifts can be ordered and delivered Christmas Eve with local express shipping in certain cities like New York and Seattle.

_Walmart.com: Wednesday, for one-day shipping before Christmas.

_Target.com: Monday and Tuesday for standard shipping, Tuesday for one-day shipping.

_JCpenney.com: 1 p.m. Wednesday with express-delivery service. By Tuesday for half-off express shipping.

_BestBuy.com: 11 a.m. Tuesday for standard shipping, and 11 a.m. Wednesday for express shipping.