MegaShipping

Shipping rates calculated from your own rules: pricing per postal code and zone, tiers by weight, cart value, measurements, volumetric weight or pallets, plus a delivery calendar with time slots and capacity per day. A Shopify app by eComm360.

Open MegaShipping from your Shopify admin (Apps > MegaShipping), or install it from its Shopify App Store listing.

Rates from your own rules. Price by postal code, zone, weight, cart value, measurements, volumetric weight or pallets, with free-shipping thresholds and surcharges.
Delivery calendar. Let the customer pick a day and a time slot, block the days you do not deliver and cap how many orders each day takes.
It tells you why. A quote log records what checkout asked for and what ruled each carrier out, so «the customer sees no shipping costs» stops being a guess.