Fits In The Box vs PackOS Checkout
Two Shopify apps, side by side: detected stores, momentum, reviews, plans, listed features and who runs each. Store counts as of Oct 13, 2026.
The short answer
- Paid plans start at $9/month for Fits In The Box and $50/month for PackOS Checkout.
- PackOS Checkout lists 8 features Fits In The Box’s listing doesn’t mention, including Address validation, Carrier-based, Flat fee.
Head to head
Starter
- · Basic product recommendations
- · Cart shipping estimate widget
- · Email support (48hr response)
- · Real-time 3D bin packing engine
- · Up to 100 synced products
- · Up to 5 box configurations
Pro
- · Analytics dashboard with insights
- · Cold chain and special handling
- · Custom packing rules and constraints
- · Multi-box packing for large orders
- · Priority email support (24hr)
- · Smart recommendations by fit + margin
Starter
- · 1,000 checkout rate calculations/mo
- · 90-day margin history
- · Box size library
- · Email support
- · Label purchasing
- · Real-time rates at checkout
Basic
- · 3,000 checkout rate calculations/mo
- · 6-month margin history
- · CSV import
- · Everything in Starter
Growth
- · 12-month margin history
- · 8,000 checkout rate calculations/mo
- · Automation rules
- · Everything in Basic
- · Priority email support
Pro
- · 20,000 checkout rate calculations/mo
- · Advanced automation rules
- · Everything in Growth
- · Multiple ship-from locations
- · Priority chat support
Coverage counts what each App Store listing names. Every feature, checked off app by app, is in Shoplist.
See every featureFits In The Box uses a 3D packing engine to show customers exactly what else fits in their current shipment. It helps merchants build bigger orders by giving shoppers a reason to add one more item. The app installs in minutes, works with your existing products and shipping rates, and handles complex scenarios like multi-box orders and cold chain requirements automatically.
PackOS solves the problem of inaccurate shipping rates at checkout. When box size is estimated incorrectly, merchants either overcharge customers and lose carts, or undercharge and lose margin. PackOS uses bin-packing logic to determine which box an order actually fits in, then queries live rates from USPS, UPS, FedEx, and other carriers for that specific package.
- Real-time 3D packing calculates remaining box space as shoppers browse
- Smart upsell suggestions highlight products that ship with no added weight
- Works out of the box—just enter your box sizes and shipping rates
- Multi-box logic splits large orders across boxes for accurate shipping
- Bin-packing engine selects the recommended box for each order automatically
- Live carrier rates from USPS, UPS, and FedEx returned at checkout
- Configurable box inventory, carrier settings, and shipping rules
All the numbers
Every figure, side by side
A green dot marks the app ahead on a measured figure. Estimates, gaps and apps that leave no storefront trace never take the lead.
Adoption
| Measure |  Fits In The Box |  PackOS Checkout |
|---|---|---|
| Detected stores | Not published | Not published |
| Net store change, 28 days | 0 | 0 |
| Stores added, 28 days | Not enough data | Not enough data |
| Big-brand share | Not enough data | Not enough data |
| Top store categories | Not published | Not published |
| Top store countries | Not published | Not published |
Reviews
| Measure | Fits In The Box | PackOS Checkout |
|---|---|---|
| App Store rating | Not published | 5.0 ★ |
| App Store reviews | Not published | 1 |
| New reviews, 28 days | Not enough data | Not enough data |
| Reviewers a year or more in | Not enough data | Not enough data |
Pricing
| Measure | Fits In The Box | PackOS Checkout |
|---|---|---|
| Free plan | Not listed | Not listed |
| Lowest paid monthly plan | $9/month(ahead) | $50/month |
| Longest free trial | 14 days | 14 days |
| Plans listed | 2 | 4 |
Listing
| Measure | Fits In The Box | PackOS Checkout |
|---|---|---|
| Shopify category rank | #458 | #391(ahead) |
| Shopify App Charts | Not on this week’s charts | Not on this week’s charts |
| Built for Shopify | No | No |
| Launched | Mar 13, 2026 | May 20, 2026 |
| Languages | 1 | 1 |
| Developer | Swagstack | PackOS |
FAQ
Fits In The Box and PackOS Checkout: common questions
- Is Fits In The Box or PackOS Checkout cheaper?
- Paid plans start at $9/month for Fits In The Box and $50/month for PackOS Checkout. Shoplist compares base prices only between monthly plans in the same currency; usage charges and annual plans vary, so check each plan’s limits.
- What features does each app list that the other doesn’t?
- PackOS Checkout lists 8 the others don’t mention, such as Address validation, Carrier-based, Flat fee, Multi-origin. A feature missing from a listing may still be supported; this compares what each App Store listing says.
- Where does this comparison’s data come from?
- Shoplist crawls Shopify storefronts to detect which apps each store runs, and reads each app’s Shopify App Store listing for reviews, pricing, features and integrations. Store counts are as of Oct 13, 2026; estimated figures are labeled.
How Shoplist compares apps
Store counts come from Shoplist’s crawl of Shopify storefronts, which detects the apps each store runs; they are as of Oct 13, 2026. Reviews, ratings, plans, features and integrations come from each app’s Shopify App Store listing. 28-day figures are labeled when estimated, and a figure that is missing or estimated never decides who leads. Read the methodology.