Shipping rates are too expensive, or not charging enough?

This is likely to be a configuration issue either in Shopify, Addition or both.  First, it's important to note how Australia Post calculates the chargeable weight, and therefore shipping rate.How_chargeable_weight_is_calculated.png

* You don’t need to cube your parcel when using Australia Post 'If It Packs, It Posts' packaging with a physical weight of 5kg or under. 

The settings you need to check

  • Given the above, the app requires product weight(s), the app pulls this detail through from your Shopify Product settings. Make sure you have assigned the correct weight for your products in Shopify.

The most common errors include no weights at all against products and/or the incorrect weight unit has been selected, e.g. 0.1 g, instead of 0.1 kg


  • Have you input product dimensions in Addition? This is how the app determines what package to use to calculate shipping, it looks a product dimensions and figures out "How many items can I fit into package a, package b" etc. The more information you provide the app with this information, the more accurate your rates will be.
  • Do you have Shipping profiles that are combining rates?  When Shipping profiles are used, Shopify takes over our calculations and will combine rates for products in different profiles. This can cause an inaccurate shipping rate. 
  • Verify that it is the Addition app providing rates at the checkout. Have you deleted Shopify's default rates or removed outdated flat rate rules that shouldn't be in place? 
  • Finally, what rate are you expecting to see?

    • Retail user, have you checked what your correct rates should be via Australia Post's calculator?  

    • MyPost Business user, have you checked what your correct rates should be via the latest MyPost Business Rates & Savings Guide
    • eParcel or StarTrack user, have you checked your contract to know what your correct rates should be? 

If all else fails reach out to support and provide us with as much information as possible so we can troubleshoot!