The mailing toolkit
USPS mail tools
From the right address to the right postage.
A few useful tools for whatever you’re mailing.
USPS Delivery Time Estimator
Estimate First-Class and Priority Mail delivery by state or use ZIP-to-ZIP USPS benchmarks when available.
Estimate delivery timeZIP+4 Lookup Tool
Enter a full address to get the 9-digit ZIP+4 code and USPS-standardized format using USPS address data.
Find a ZIP+4 codePostage & envelopes
Work out the size, stamps, and cost.
USPS Mailing Cost Calculator
Calculate letter postage and compare USPS package estimates using weight, dimensions, and destination.
Envelope Size Finder
Find an envelope for your paper or card, see how it fits, and compare common envelope dimensions.
Certified Mail Fee Calculator
Calculate total USPS Certified Mail costs including postage, service fees, Return Receipt, and Restricted Delivery options.
Addresses & ZIP codes
Check the details before you send.
USPS Address Validator
Verify and correct U.S. addresses against USPS address data. Get ZIP+4 codes and standardized formatting.
ZIP Code Validator & City/State Lookup
Check if a ZIP code is valid and see its primary city and state using USPS city/state data.
USPS-Style Address Standardizer
Clean up capitalization, street abbreviations, and ZIP formatting. Formatting only—not address verification.
Tracking & updates
See where your mail is and what the status means.
Tools inside our guides
Open a finder or calculator alongside the instructions that explain it.
IRS Mailing Address Finder
Find mailing guidance by form, state, payment, and delivery method, with links to the official IRS instructions.
50-State DMV Checker
Find online options and mail-in guidance for registration renewals, replacement titles, and license renewals in all 50 states and DC.
Letter Stamp Calculator
Estimate the number of stamps for a letter using its weight or an approximate sheet count.
Military Address Format Checker
Check APO, FPO, and DPO address formatting and missing details. This is not delivery-point verification.
International Tracking Coverage Checker
See tracking coverage by USPS service and participating destinations for First-Class packages.
Destination Postal Tracking Finder
Find the destination postal service's tracking page to check for updates after mail leaves the U.S.
USPS Open Today Checker
Check whether regular mail service is scheduled today using the 2026 USPS holiday calendar, then find local Post Office hours.