Why we show you the carrier's numbers before charging an adjustment

Ask a small online seller what annoys them most about discount shipping platforms and price rarely comes first. The quotes are fine. What gets them is the charge that turns up weeks later.

“I was just told that our package grew 50lb two weeks after it was sent. So they automatically charged my card $170.”A seller reviewing a Canadian shipping platform on Trustpilot, July 2026

“These guys prices are good during QUOTE but I can assure you that is not the price you will pay.”A review of another platform, September 2026

Before building ProtonShip we read about 1,200 reviews and forum posts from Canadian sellers. Around 70 described a charge that arrived after the parcel had shipped. So we built the part that happens after the label first.

What a carrier adjustment is

Every carrier weighs and measures parcels at its depots. If the box is heavier or bigger than the label says, if the address needed correcting, or if a parcel labelled for a business went to a home, the carrier bills the difference. It bills whoever owns the account the label was bought through, and that bill often arrives weeks after delivery.

A shipping platform then passes the charge on to you, and platforms differ in how they do it. Some platforms’ terms let them charge the card on file at any time after the parcel ships, even after delivery, and treat the carrier’s measurement as final. You find out from your card statement or a short email, usually without the carrier’s figures.

What ProtonShip does instead

1. When a carrier posts an adjustment, we put it on the shipment with your figures next to the carrier’s: the weight and size you entered, and what they measured.
2. We email you the reason, the amount and the date it will be charged.
3. Nothing is charged for 72 hours. If you dispute it in that time, the charge waits while we check.
4. After the charge, you can still dispute it for 30 days. If we agree, the full amount goes back to your card.
5. If a charge is declined, new labels pause until it’s paid. Labels you already bought keep working.

None of this is complicated. It means the money stays in your account while you look, and that you have the carrier’s numbers to look at. See how adjustments work.

What this doesn’t fix

We can’t stop carriers re-measuring, and we wouldn’t want to; the price you pay is set by the parcel you send. A notice period also can’t make a late adjustment early. The 72 hours start when the carrier’s charge reaches us, so a carrier that bills six weeks after delivery still bills six weeks after delivery. What changes is that you see it, with figures, before your card does.

Most adjustments start before the parcel leaves, with a box measured before it was packed or weighed without the filler.

• Measure the closed, packed box at its widest points, and round each side up to the next inch.
• Weigh it with everything inside and round up.
• Save the boxes you use, so the same box goes in the same way every time.
• Mark homes as homes, and include the unit number.

Our parcel size calculator shows the billable weight of a box at all five carriers, which is where most size adjustments start.