01Platform or pocket
A platform scale handles boxed sneakers, bundles of clothes and anything up to its limit. A pocket scale reads to a tenth of a gram, so you can tell whether a card mailer sits a fraction under an ounce break.
Choose the platform size that fits your usual box, and keep the pocket scale within reach for mailers.
02Weighing before you buy the label
Weigh the packed package, with tape and packing slip inside, before you buy the label. Boxes and bubble wrap add more weight than the item alone suggests.
Round up to the next ounce when you enter the weight. USPS audits label weights, and Pirate Ship, eBay and Etsy pass any adjustment back to you.
03Keeping it accurate
Tare the scale on a flat surface and check it now and then with something of known weight, like an unopened 1 lb pack of butter or a 5 lb bag of flour.
Replace the batteries when the display dims, because the reading drifts on a weak battery.