Combined rates
Updated · SMART Shipping Rates (E-TRADE PARTNER)
Use Combined rates to blend tagged SMART calculated rates into one checkout method. Blend options are Sum, Cheapest, Most expensive, and Average. Because combined rates are calculated rates, Shopify Carrier Service is required.
4.9 · SMART Shipping Rates does this with zones, calculated rates, and delivery customizations.
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Combined rates are useful when several rate components match the same cart. For example, a base zone rate and a product surcharge may both be valid, but the customer should see one clear shipping method instead of several partial prices.
Calculated rates only
Combined rates work with tagged calculated rates from Shipping rates. They need Shopify Carrier Service because SMART returns the blended result to checkout.
Blend methods
| Method | What it does | Common use |
|---|---|---|
| Sum | Adds matching tagged rates together | Base rate plus surcharge |
| Cheapest | Uses the lowest matching rate | Choose the lowest valid calculated option |
| Most expensive | Uses the highest matching rate | Use the safest price for mixed carts |
| Average | Averages the matching rates | Smooth several similar calculated rates |
How shipping tags fit in
Shipping tags mark which calculated rates belong together. Add tags in Shipping rates, then use those tags in Combined rates so SMART knows which rate components can be blended.
- Use clear internal tags such as base-zone, fragile-fee, or remote-surcharge.
- Do not reuse a tag for unrelated rates that should never appear together.
- Keep the customer-facing combined method name simple, such as Standard delivery.
Setup steps
- Open Shipping rates and confirm Carrier Service is available. The notice appears when it is not.
- Create the individual calculated rates in Shipping rates.
- Add shipping tags to the rates you may want to blend.
- Open Combined rates and create a combined rate.
- Choose the tags that should be included.
- Select Sum, Cheapest, Most expensive, or Average.
- Test carts that trigger one tagged rate, several tagged rates, and none of the tagged rates.
When not to combine rates
Do not combine methods that represent different customer choices. If Local delivery, Pickup, and Standard delivery should remain separate options, use Delivery customizations to hide, show, move, rename, or sort them instead.
For more examples, read the rate blending guide or return to the docs overview.
Blend calculated rate parts into one checkout method
Use SMART to combine tagged calculated rates with sum, cheapest, most expensive, or average logic.
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Frequently asked questions
›Do combined rates require Carrier Service?
Yes. Combined rates return a calculated blended rate to checkout, so Shopify Carrier Service is required.
›Which blend methods are available?
SMART supports Sum, Cheapest, Most expensive, and Average.
›Do I need shipping tags?
Yes. Shipping tags identify which calculated rates should be considered for blending.
›Can I combine existing Shopify methods?
Combined rates are for tagged calculated SMART rates. Use Delivery customizations when you need to control existing methods.