How Long Does Mail Take? ZIP-to-ZIP USPS Calculator

How many days does First-Class Mail take?

2 to 5 delivery days, depending on how far apart the two ZIP codes are. Most pairs of areas are 3 to 5 days apart; USPS delivers about 9 in 10 pieces within the standard.

Shares are of the 914 × 929 pairs of 3-digit ZIP areas in USPS's directory, each pair counted once, not weighted by how much mail travels it. On-time figures are USPS's national results for single-piece First-Class Mail.

Why does USPS sometimes say 1 to 5 days?

The 1-day standard is for presorted business mail. A card or letter you drop in a mailbox is single-piece First-Class Mail, and its standard starts at 2 days.

In the same USPS directory, the presort column has 5,969 overnight pairs of areas. The single-piece column, which this calculator reads, has none.

Why does a card mailed on Friday seem slower?

Because Sunday doesn't count. The day you mail it is day 0, and each Monday-to-Saturday delivery day after it counts one, so a 3-day card mailed on a Friday arrives on Tuesday, and one mailed on a Monday arrives on Thursday.

Which days are USPS holidays?

USPS doesn't deliver ordinary mail on the eleven federal holidays. When one falls on a Sunday, the Monday after is the day off; when one falls on a Saturday, that Saturday is, and the Friday before has normal delivery.

Why do two ZIP codes in the same area give different answers?

USPS sets most standards by 3-digit ZIP area, but it lists 13,333 individual ZIP codes separately, each slower than its area to some destinations, almost always by one day.

A few dozen ZIP codes are two days slower to a handful of nearby areas. The calculator reads the 5-digit listing first, as USPS's directory specifies, so two neighbours can get different answers.

How do I make sure a card arrives on time?

Mail it one delivery day earlier than the standard needs. USPS delivers about 95 in 100 First-Class pieces within one day of the standard (96 in 100 on 2-day routes).

December is the busiest month. For Christmas, USPS recommends mailing First-Class by December 17 (USPS 2026 holiday dates). Mailing a stack yourself? The stamp calculator works out the postage for any card format and quantity.

Is a USPS service standard a guarantee?

No. It's the target USPS sets itself. In April to June 2026, it delivered 88.7% of single-piece First-Class Mail on 3-to-5-day routes on time, and 98.4% within three days of the standard.

How this calculator works

It reads USPS's First-Class Mail service standard directories, effective July 1, 2026, from USPS PostalPro: a table of 914 origin areas by 929 destination areas, plus the individual ZIP codes USPS lists separately. The on-time odds are USPS's national quarterly results for April to June 2026. It counts delivery days from the mailing date, skipping Sundays and USPS holidays.

What it can't know: your collection box's last pickup, whether a particular 5-digit ZIP code exists within a valid area (it answers from the area), weather, and mail sent from military addresses, which USPS's table doesn't cover. The page downloads the part of USPS's table that your first ZIP code's first digit points to; the ZIP codes you type aren't sent anywhere.

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