Show the estimate inputs and unavailable states
Show a supported estimate, an unavailable route and an unknown estimate as different cart states. Recheck the selected products and destination whenever the cart changes. The matrix identifies rules to validate; it supplies no actual carrier price, service boundary or delivery promise for the business.
Worked example — illustrative data.
| Cart condition | Expected specimen state | Source needed |
|---|---|---|
| Standard item, supported postcode | Estimate with scope and assumptions | Approved carrier/rule table |
| Oversized lamp | Explain size-dependent restriction | Actual product dimensions and shipping policy |
| Unsupported destination | No delivery available; supported alternative if real | Owner-approved service boundary |
| Mixed cart | Show combined rule or request review | Actual split-shipment logic |
| No postcode yet | Ask for location before estimate | Required input and privacy review |
List product attributes and destination inputs that change fulfilment. Give every rule an owner and an update date. Use synthetic addresses or postcodes in an approved test environment, then compare the displayed estimate with the configured rule. Explain whether tax, handling or split shipments are included when the business’s actual calculation requires it. Keep a route to the full delivery policy next to the estimate.
An oversized addition can invalidate a previous estimate
Adding an oversized product can invalidate a previously valid cart estimate. Recalculate or clearly explain the pending state; do not leave the earlier figure displayed as though it still covers the whole order.
Accept the estimator when each defined state gives a truthful next action and the final review uses the selected cart and destination. The matrix does not supply real shipping rates.
Continue with Guides for stores, software teams and local businesses, eCommerce website design and development and Design store pickup pages that answer availability questions.