Frequently asked questions
Send letters and cards
Sizes and weights
14 questions
 for the keyword « Sizes and weights »
How do I calculate the price for sending my letter?
The price of your letter depends on:
  • the speed you desire (priority or non-priority delivery)
  • the size and weight of your letter
Use our online tool to calculate the price of your letter quickly. Enter the destination and the weight of your letter to find out how many and which stamps to put on your letter.
Can I send letters of any size?
Your letter or card can have any shape or size, but if it's not the standardised dimension then you will have to pay a surcharge. A standardised letter or card is always rectangular with the following characteristics:
  • Minimum 90 x 140 mm
  • Maximum 125 x 235 mm
  • Maximum 50 g
  • Maximum 5 mm thick
Use our online tool to calculate the price of your letter quickly.
Where can I find the price of non-standardised mail?
You can calculate the price of your non-standardised letter on our website. Look at our table with prices.
What can/can't I send with an envelope?
Look in the General Terms and Conditions to see what you cannot send in a letter. When sending objects, it's best to use a reinforced envelope or send it as a parcel.
Are (really) old stamps still valid?
You can continue to use old stamps. All stamps from October 2, 1961, including those in Belgian francs, remain valid for:
  • a non-priority mail within Belgium
  • International mail. In this case you should also stick a blue A Prior label on your mail.
You cannot use old stamps as priority stamps. If you want to send your mail as a priority mail, you will need a priority stamp with a barcode.
How do I stamp my standardised letter?
The number of stamps on your non-standardised letter depends on the weight of your letter. Look at the table on our website or calculate the price with the online tool.
I didn't put enough stamps on my letter. How do I rectify the error?
As soon as your letter is sent, you cannot change it. If you wrote a return address on the back, the letter will be returned to you.
When does my letter become a parcel?
Letter or parcel: a letter becomes a parcel if it exceeds at least one of the following dimensions:
  • 230 mm in width
  • 350 mm in length
  • 30 mm in height
  • 2 kg
Do the contents determine whether I am sending a letter or a parcel?
The size determines whether your item is sent as a letter or a parcel. A letter becomes a parcel if it exceeds the following dimensions and weight:
  • 230 mm in width
  • 350 mm in length
  • 30 mm in height
  • 2 kg  
Where do I drop off my non-standardised letter?
You can place your non-standardised letter in one of the many bpost mailboxes. If your envelope doesn't fit in the opening, drop it off in a Post Office.
Will my non-standardised mail be delivered later?
We deliver your non-standardised mail just as quickly as standardised letters.
What's the best way to weigh my letter?
You can weigh your letter at home. Or you can have your letter weighed in a Post Office in your neighbourhood.
Can I send a non-standardised letter as registered mail?
You can send your non-standardised letter as registered mail.
How many stamps should I put on my letter?
The number of stamps and which stamp(s) to attach to your envelope depends on:
  • the destination
  • the speed you desire (priority or non-priority delivery)
  • the size and weight of your letter
Use our online tool to calculate the price of your letter quickly. Enter the destination and weight of your letter to find out how many and which stamps to put on your letter.