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Honest comparison

PackOS vs Shopify Shipping: what your checkout is missing

Shopify Shipping gives you basic carrier-calculated rates and discounted labels. PackOS adds bin-packing box optimization, dimensional weight accuracy, and automatic margin analytics — the pieces PackOS adds on top.

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14-day free trial on the plan you choose

Shopify Shipping is a solid starting point that works for many stores. This is a fair comparison of where it stops and where PackOS picks up.

The core gap

Weight is not enough

Shopify calculates checkout rates using product weight. But carriers charge based on whichever is greater: actual weight or dimensional weight. Without knowing the box dimensions, your checkout quotes are guesses — and those guesses cost you money.

Works out of the box on higher-tier plans. Rates are calculated from product weight only — no box optimization, no dimensional weight accuracy.

Installs in minutes. Determines the right box for every order, then returns accurate rates from USPS, UPS, and FedEx simultaneously at checkout.

Detailed feature comparison

A side-by-side look at what each platform offers. A checkmark where a capability is built in, and a note where the answer depends on your own setup.

FeaturePackOSShopify
Box optimization at checkoutAutomatically determines the optimal box for each order before quoting carrier ratesBuilt inReal bin-packingDepends on what your checkout collects
Multi-carrier live ratesShows rates from USPS, UPS, and FedEx simultaneously at checkoutBuilt inUSPS + UPS + FedExSee Shopify’s shipping settings for what it supports
Dimensional weight accuracyAccounts for package dimensions, not just weight, when quoting ratesBuilt inReal bin-packingDepends on what your checkout collects
Split shipment logicAutomatically splits orders across multiple boxes when items do not fit in oneBuilt inSee Shopify’s shipping settings for what it supports
Shipping margin analyticsTracks the gap between what the customer paid and what the label costBuilt inAutomaticDepends on what your checkout collects
Discounted label purchasingBuy carrier labels at discounted platform ratesBuilt inDiscountedBuilt inShopify Shipping rates
Batch label printingPrint labels for multiple orders at once from a single dashboardBuilt inSee Shopify’s shipping settings for what it supports
Setup timeTime from install to live, accurate checkout ratesMinutes, no codeBuilt in (limited accuracy)

When Shopify Shipping is enough

  • Stores with uniform product sizesIf every order ships in the same box and weight is predictable, Shopify’s weight-based rates are close enough. Bin-packing adds less value when there is only one box to choose from.
  • Flat-rate or free shipping storesIf you charge a flat shipping fee or offer free shipping, checkout rate accuracy is irrelevant. Shopify Shipping labels still give you discounted rates for the fulfillment side.
  • New stores on a tight budgetShopify Shipping is included with your plan — no extra cost. For stores just getting started, it is a reasonable default until volume and product variety make accuracy more important.

When you need more

  • Stores with varied product sizesIf your catalog includes items of different dimensions and orders often combine multiple products, bin-packing ensures the right box is selected for every order — and rates reflect actual shipping cost.
  • Stores losing money on shippingIf you suspect shipping is a cost center but cannot prove it, PackOS margin analytics show exactly how much you make or lose on shipping for every order. No spreadsheets, no manual matching.
  • Stores that need multi-carrier comparisonPackOS queries USPS, UPS, and FedEx simultaneously and shows your customers the best options. Shopify limits carrier availability based on your plan tier.
  • Stores with dimensional weight issuesIf you ship lightweight but bulky items, carriers charge dimensional weight — and Shopify does not account for it at checkout. PackOS does, automatically.

Switching

Moving from Shopify’s own rates

  • Install PackOS Checkout and add your box library; your existing shipping profiles stay in place until you switch them off.
  • Turn on PackOS Checkout as a rate provider in Shopify’s shipping settings, then compare rates on a test checkout.
  • Nothing to cancel: PackOS Checkout bills through Shopify and the 14-day trial applies to the plan you choose.

Accurate rates. Real margin data. No code.

PackOS adds bin-packing, multi-carrier rates, and margin analytics to your Shopify checkout.

One order · Two numbers · One difference

Quoted at checkout

What the customer paid you to ship it

PackOS Checkout

Paid for the label

What the carrier charged you to move it

PackOS Labels

Margin

The difference, recorded on every order

Both products, on the same record

Run either product on its own. Run both and the same order carries both numbers.

Common questions

Frequently asked questions

Does Shopify Shipping already calculate rates at checkout?
Shopify offers carrier-calculated shipping rates on Advanced and Plus plans, but it uses product weight alone to estimate rates. It does not run bin-packing to determine which box to use, so dimensional weight is not accounted for. This often leads to inaccurate checkout quotes — customers may be overcharged or undercharged depending on the size of the items.
Can I use PackOS and Shopify Shipping at the same time?
You replace Shopify's built-in carrier-calculated rates with PackOS rates. PackOS installs as a carrier service in Shopify, so your checkout shows PackOS-calculated rates instead of the default Shopify rates. There is no conflict — PackOS simply provides more accurate rate quotes.
What is bin-packing and why does it matter?
Bin-packing is the process of determining which box (or combination of boxes) best fits the items in an order. Without bin-packing, rate calculations use product weight only and ignore how items physically fit together. This means dimensional weight surcharges are missed at checkout, leading to inaccurate shipping quotes. PackOS runs bin-packing on every order before querying carriers.
Is PackOS worth it if I already have Shopify Advanced?
Shopify Advanced gives you access to carrier-calculated rates, but it does not include bin-packing or dimensional weight accuracy. PackOS Checkout adds box optimization, multi-carrier rate comparison, and split shipment logic. Pair it with PackOS Labels and the order also carries its shipping margin.
How much does PackOS cost compared to Shopify Shipping?
Shopify Shipping rates are included with your Shopify plan — no extra charge for the rate calculation. PackOS Checkout starts at $50/month through the Shopify App Store, with a 14-day free trial on the plan you choose. PackOS Labels is free, always — no monthly subscription and no markup on postage; you pay the carrier price shown for each label.

See what your checkout is missing

PackOS Checkout: 14-day free trial on the plan you choose. PackOS Labels: free, always.

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