Weigh the completely packed and sealed mailpiece—not the contents or empty envelope—and use a scale whose capacity and resolution fit the item.
What to look for in a postage scale
| Feature | Why it matters |
|---|---|
| Maximum capacity | The finished package must remain within the scale’s range. |
| Resolution | Small increments matter near a USPS price or eligibility boundary. |
| Platform size | The item should not hide the display or rest on another surface. |
| Tare | Useful for packing workflows, but the purchased label needs the final gross weight. |
| Units and stable reading | Avoid ounce, pound and gram entry mistakes. |
How to weigh mail for USPS postage
- Pack the contents exactly as they will be mailed.
- Seal the envelope or package and attach ordinary packing materials.
- Place the entire item on the center of the scale.
- Wait for a stable reading and record the units.
- Measure the final outside dimensions.
- Enter the values into the current USPS or authorized-provider workflow.
When the weight is close to a boundary
Repeat the measurement on a level surface and check the scale with a suitable reference or its documented calibration procedure. Do not round down to force the item into a lower bracket. If the reading is unstable or too close to call, use a reliable second scale or take the finished item to a Post Office.
Why accurate entry matters
USPS Automated Package Verification can compare entered weight and dimensions with postal measurements and apply an adjustment when they differ. A home scale helps prepare the shipment, but USPS retains the final mailing determination.
After obtaining the finished weight, use the postage and stamp calculator for the appropriate mailpiece path.
Sources and update note
Facts and availability checked September 10, 2026.