Every online store has a moment where a customer goes from "just looking" to "I'll take it". That moment is the shopping cart — the part of an e-commerce website that lets customers collect products or services, review their order and move on to checkout. If you're still getting familiar with what an e-commerce website is, that guide is a good place to start.
A modern shopping cart can support:
- Products
- Product variations
- Quantities
- Prices
- Discounts where configured
- Shipping or delivery options where applicable
- GST/tax where applicable
- Order totals
- Checkout
- Payment
- Order confirmation
Exactly what a cart does depends on how the store is designed and which payment, shipping and business systems are connected to it.
Quick answer
In simple terms: a shopping cart temporarily keeps the items a customer intends to buy, calculates the current order total, and passes that order information into the checkout process.
- 1Browse products
- 2Select product
- 3Add to cart
- 4Review cart
- 5Checkout
- 6Payment
- 7Order confirmation
- 8Business processes order
What Is an Online Shopping Cart?
An online shopping cart works like a basket in a physical shop. Customers put items in, take items out and change quantities while they browse. When they're ready, they take the basket to the counter — online, that's checkout.
Online stores need a cart because most customers buy more than one thing, or want to compare before committing. A simple enquiry form is different: it sends a message ("I'm interested in this") and someone has to reply with a price. A cart lets the customer see the price, build the order and pay without waiting.
The cart is the bridge between your product catalogue and checkout. It takes what the customer picked on product pages and hands a clean, priced order to checkout.
What Happens When a Customer Clicks "Add to Cart"?
Step 1 — Customer selects a product
On the product page, the customer chooses:
- The product
- Quantity
- Size or variation where applicable
- Colour or option where applicable
Step 2 — Product is added to the cart
The cart records the item along with everything needed to price it — which variation, how many, and the current price.
Step 3 — Customer continues shopping
The customer can go back to the catalogue and add more. The cart keeps a running list in the background, often with a small item count in the header.
Step 4 — Customer opens the cart
The cart shows a summary of the current order. A typical cart displays:
- Product name
- Product image
- Quantity
- Unit price
- Subtotal
- Delivery/shipping cost where applicable
- Discounts where applicable
- GST/tax where applicable
- Order total
How Is the Shopping Cart Total Calculated?
Here's a simple example:
| Item | Price | Qty | Line total |
|---|---|---|---|
| Product A | $40 | 2 | $80 |
| Product B | $25 | 1 | $25 |
| Subtotal | $105 | ||
The final amount the customer pays may also include:
- Delivery or shipping
- Discounts or promo codes
- GST
- Other charges the store has configured
Stores don't all calculate these the same way — some show prices including GST, some calculate shipping by weight or postcode, and some offer free delivery over a set amount.
What Happens When the Customer Goes to Checkout?
When the customer clicks "Checkout", the cart hands over the order and the website starts collecting what it needs to complete the purchase. A typical checkout asks for:
- Customer name
- Email address
- Phone number where required
- Billing information
- Delivery address where applicable
- Delivery option
- Payment method
Every extra step or field is a chance for a customer to give up, so a good checkout asks only for what it genuinely needs. Customers in 2026 expect:
- A mobile-friendly checkout
- A clear order summary
- Clear pricing with no surprises
- A secure payment experience
- Sensible validation
- Clear error messages
- Easy navigation back to the cart
How Does Online Payment Work After Checkout?
The cart, checkout and payment provider each play a part:
- 1Shopping cart
- 2Checkout
- 3Payment provider
- 4Payment authorisation
- 5Payment result
- 6Order confirmation
Payments are generally handled by a dedicated payment provider. The customer's card details go to the provider, which checks with the bank and sends back a result. The website doesn't need to store raw card numbers.
Depending on the payment provider and website configuration, Australian online stores may offer:
- Credit and debit cards
- Apple Pay
- Google Pay
- PayPal
- Buy now, pay later services
What Happens If the Payment Fails?
Payments can fail for ordinary reasons, such as:
- Insufficient funds
- Card declined by the bank
- Extra authentication required (e.g. a bank app approval)
- The payment session expired
- The customer cancelled
- A technical or network interruption
A good checkout tells the customer clearly what happened, keeps their cart intact and lets them try again or choose a different method where appropriate.
What Happens After a Successful Payment?
- 1Payment successful
- 2Order created
- 3Order number generated
- 4Customer confirmation
- 5Business notification
- 6Order processing
- 7Fulfilment / delivery
The exact workflow varies by business, but typically includes:
- An order confirmation page with the order number
- A confirmation email to the customer
- A notification to the business about the new order
- An order status (e.g. new, processing, shipped) the business can update
- Fulfilment — packing, preparing or scheduling the order
- Delivery to the customer, or collection in store
How Does the Business Manage Orders?
Behind the scenes, orders land in the store's administration area. Depending on the setup, an administrator may be able to:
- View orders
- Search orders
- View customer details
- View purchased products
- Update order status
- Manage products
- Manage categories
- Update inventory where supported
- Manage website content
What Happens to the Shopping Cart if the Customer Leaves?
Whether a cart is still there when a customer comes back depends on how the website is built. Carts may be kept using:
- Browser or session storage
- Cookies
- Server-side sessions
- Customer accounts
- Other application mechanisms
So an abandoned cart isn't always saved — closing the browser, switching devices or clearing cookies can empty it.
Cart persistence
Keeping the items in the cart so they're still there when the customer returns.
Abandoned cart recovery
Actively reminding customers — for example by email — that they left items behind. This needs to be specifically set up and must respect consent and privacy rules.
Can Customers Shop Without Creating an Account?
Often, yes — this is called guest checkout. Stores may offer guest checkout, account checkout, or a choice of both.
Guest checkout
- Faster purchase
- Fewer barriers
- Suits first-time customers
Customer accounts
- Order history
- Saved addresses
- Faster future checkout
- Account-specific information
Neither is best for every store — it depends on how often your customers buy again.
How Does a Shopping Cart Work on Mobile?
Many customers shop on their phones, so the cart and checkout need to be just as easy on a small screen. That means:
- Responsive product pages
- Large, easy-to-tap buttons
- Simple quantity controls
- A clear cart summary
- A mobile-friendly checkout
- Fast page loading
- The right keyboard for each form field
- Payment methods that suit mobile devices
How Does a Shopping Cart Support Different Products?
Simple products
One version, one price — e.g. Coffee, $15.
Product variations
T-shirt — Size: Small / Medium / Large; Colour: Black / White. Each combination is its own line in the cart.
Multiple quantities
3 × the same product, priced as one line.
Different product types
Physical goods, services, bookings or gift vouchers may each need different checkout steps.
The exact implementation depends on the platform and the business's requirements.
Shopping Cart vs Checkout — What Is the Difference?
Think of the cart as "what I'm buying" and checkout as "how I'm paying and receiving it".
| Shopping cart | Checkout |
|---|---|
| Shows selected products | Collects purchase information |
| Allows quantity changes | Collects customer details |
| Calculates the cart subtotal | Calculates the final order |
| Allows removing products | Collects delivery information where required |
| Lets the customer keep shopping | Processes payment |
| Prepares the order | Completes the transaction |
How We Build Shopping Cart Functionality
At Premium Websites, we build the cart as part of a complete online store — from product structure through to admin management. Here's the typical sequence:
- 1Business requirements
- 2Product structure
- 3Product pages
- 4Shopping cart
- 5Checkout
- 6Payment integration
- 7Order management
- 8Admin management
- 9Testing
- 10Launch
The details depend on each client's products, platform and integrations. If you'd like to see what a complete store involves, explore our e-commerce and booking website solutions.
How We Prepare E-commerce Websites for Future SEO
That's why we plan these foundations from the start:
- Logical product and category structure
- SEO-friendly URLs
- Crawlable product pages
- Unique product content
- Internal linking
- Category navigation
- Page titles
- Meta descriptions
- Heading structure
- Image optimisation
- Mobile responsiveness
- Performance
- XML sitemap
- Structured data where appropriate
- Room for a future blog or content section
Good foundations make future SEO work more effective — but no one can honestly guarantee rankings.
See How a Shopping Cart Works in Practice
A walkthrough of the journey on an e-commerce demo:
1. Product page
The customer sees photos, price, options and an Add to Cart button.
2. Add to cart
The selected product, option and quantity are recorded in the cart.
3. Shopping cart
A summary of items, quantities and the running subtotal.
4. Checkout
Customer and delivery details are collected, then payment.
5. Order confirmation
The customer sees their order number and receives a confirmation.
6. Full walkthrough video
The whole journey from product page to order confirmation.
E-commerce Shopping Cart Features
- Product selection
- Product variations
- Quantity management
- Cart subtotal
- Discounts where configured
- Delivery/shipping options where applicable
- GST/tax handling where applicable
- Checkout
- Payment integration
- Order confirmation
- Customer notifications
- Admin order management
- Mobile-friendly experience
Features depend on each project's requirements and integrations.
Frequently Asked Questions
Related E-commerce Guides
- What Is an E-commerce Website?
- Shopify vs WooCommerce in Australia
- What Does an E-commerce Website Include? Coming soon
- How Do Online Payments Work? Coming soon
- How Does an E-commerce Admin Dashboard Work? Coming soon
- How We Build an E-commerce Website Coming soon
- How We Build E-commerce Websites for Future SEO Coming soon
Planning an E-commerce Website?
A modern online store can bring together products, a shopping cart, checkout, payments, order management and administration — plus bookings where your business needs them. See our e-commerce website design and booking solutions or explore the full service.