Upselling and Cross-Selling: Grow Your Average Order Value

One of the most important numbers in any business is average order value: how much a customer spends, on average, every time they buy. The simplest and cheapest way to increase it is an additional sale, meaning a relevant product or service offered to a customer who has already decided to buy.

The logic is straightforward. Winning a new customer costs money: advertising, sales time, introductory discounts. A customer who is already in your cart or at your counter trusts you; all they need is the right offer at the right moment. Yet many businesses avoid additional sales because they feel like pushing people to buy things they don't need.

The difference between an annoying upsell and a helpful one comes down to approach. When the offer solves a real problem for the customer, it becomes part of the service. In this guide we cover:

• the difference between upselling, cross-selling and downselling;
• why you should track average order value and how to calculate it;
• 10 proven tactics to increase average order value;
• how to add additional sales to your website and online store;
• how to automate them through your CRM, messaging apps and email;
• how to measure results and which mistakes to avoid.

What upselling, cross-selling and downselling mean

An additional sale is any offer made after the customer has already chosen a product or service and is ready to pay. It comes in three main forms, and it is worth knowing all of them, because each one fits a different moment in the buying journey.

Upselling: a better version of the same product

With an upsell, you offer the customer a more advanced or premium version of what they have already chosen. For example, a laptop with more memory, a two-year hosting plan instead of one year, or an extended facial instead of a basic one. The customer still buys one product, just at a higher tier.

Cross-selling: a complementary product

With a cross-sell, you offer an additional product or service that complements the purchase: a case and screen protector for a new phone, bedding for a new bed, or installation and maintenance for an air conditioner. The customer gets a complete solution instead of a single item.

Downselling: a cheaper alternative

A downsell works in the opposite direction. When you can see the customer hesitating because of the price, you offer a simpler or cheaper version. The goal here is not a bigger basket but keeping the customer, and someone who buys the basic version today may well come back to upgrade later.

Why track average order value and how to calculate it

Average order value (AOV) is easy to calculate: divide total revenue for a period by the number of orders in that same period. As an illustrative example, if a store made €60,000 from 300 orders in a month, its average order value is €200.

Revenue depends on three factors: how many people visit, how many of them buy, and how much each buyer spends. Most businesses invest mainly in the first factor, through advertising and promotion. Raising average order value, however, improves your bottom line directly without a bigger ad budget: every extra euro added to an existing order costs you almost nothing in acquisition.

There is an indirect effect too. When average order value goes up, you can afford to pay more for each new customer in advertising and still stay profitable. That gives you an edge over competitors bidding for the same audience on Google and Meta. We cover the other numbers worth watching in our guide to ecommerce metrics for online stores.

10 tactics to increase average order value

These tactics fall into two groups: those related to the offer itself, and those related to your ongoing relationship with the customer. Start with one or two that suit your business and add more over time.

1. Time-limited offers

A sense of urgency helps customers decide now rather than later. The calendar gives you plenty of occasions: Black Friday, the winter holidays, back-to-school season and end-of-season sales. A one-week promotion on an add-on or an upgraded version encourages customers to add something they had not planned to buy.

For example, before the holiday season a hair salon could offer a restorative hair treatment at a special price for one week to anyone booking a colour appointment. The promotion must be genuine: customers quickly spot "discounts" on a price that was raised the day before, and lost trust is hard to win back.

2. Product and service bundles

Instead of selling every product separately, offer bundles of items that work well together: a gym membership with an introductory session with a trainer, a car service with a wash, a website with a one-year maintenance plan. A good bundle solves a whole problem, so the customer does not have to work out what else they might be missing.

The principle works in any industry. An electrician installing sockets in a home with small children can offer socket safety covers. Many parents don't even know the option exists and are glad to hear about it. Both sides win: the tradesperson earns more, and the customer gets something genuinely useful.

3. The 25 percent rule

A common rule of thumb says the suggested add-on should cost no more than about a quarter of the original purchase. Someone buying shoes for €100 is unlikely to add a €60 protective spray, but they may well add a €20 care kit.

This is not a law of nature, just a starting point. Test what works for you: in some categories customers are willing to add more, for example when the add-on is an extended warranty on an expensive product.

4. The rule of three options

Don't offer more than three products or services at once. Too many choices tire customers out, and instead of choosing, they simply give up. The usual approach is three tiers: basic, standard and premium. Most customers pick the middle one, and the premium tier makes the standard option look like good value.

This works both in a physical store and online. On a phone's product page, you can show three popular accessories at different price points rather than a carousel of twenty items.

5. Samples and vouchers

Add a small sample of another product to each order. The customer gets to try something new with no risk, and there is a good chance they will buy it next time. The same idea works with a voucher for a complementary service: a regular haircut client can receive a voucher for a scalp treatment and add it at their next visit.

6. Convenient payment options and instalments

It is easier to commit to a bigger purchase when paying is convenient. Many customers now expect to split larger purchases into instalments or use a buy-now-pay-later option, and online stores should also accept digital wallets such as Apple Pay and Google Pay. When customers see that an upgrade adds only a small amount to each instalment, saying yes becomes much easier.

Check with your payment provider which methods are available in your markets, and show the instalment option on the product page, not only at checkout.

7. Reminders by messaging app, SMS and email

Messages to existing customers are one of the cheapest ways to increase sales. You can remind people when it is time to reorder, ask for a review after a purchase and share relevant promotions. Messaging apps are a natural channel for this: the WhatsApp Business app works for small volumes, and the WhatsApp Business Platform handles messaging at scale. Email remains the backbone for most stores.

Mind the rules. In the EU, the ePrivacy rules and the GDPR generally require prior consent before you send marketing messages by email, SMS or messaging app, with a narrow exception for similar products offered to existing customers in some countries, and every message must include an easy way to opt out. This is not legal advice; check the requirements in each country you sell to. We explain how to build such a channel in our guide to messenger marketing.

8. RFM segmentation of your customer base

RFM segmentation groups customers by three measures: how recently they bought (Recency), how often they buy (Frequency) and how much they spend (Monetary). The idea draws on the Pareto principle: a small share of customers usually brings in a large share of revenue. It pays to identify those customers and communicate with them personally, rather than only chasing new ones.

Here is what it looks like in practice. A beauty salon can track each client's last visit and send messages such as:

• "It's been three weeks since your last manicure. Would you like to book an appointment?"
• "We haven't seen you for six months. A discount is waiting for your next visit; just reply to book."
• "It's been a month since your colour. Now is a good time to refresh the shade."

9. Social proof

For a customer to add something to the basket, they need a reason to believe it is worth it. The best way is to show honestly what is good about the product and how many other customers choose it: "best seller this month", "customers who bought this also added", star ratings and reviews on the product page.

Honesty matters most here. If you present a product as a hit while customers see negative reviews of it on Google, trust takes a hit. That is why reputation management matters: collect positive reviews and display them on your site and product pages, and reply quickly and constructively to negative ones too. A fast response with a solution and a perk for the next purchase often turns a disappointed customer into a repeat one.

10. A loyalty programme

A loyalty programme gives customers a sense of special status while also growing the basket. You can offer members private sales, tiered benefits based on spend, points or cashback towards the next purchase. When customers see a clear gain, they find it easier to spend a little more than planned, for example to reach the free shipping threshold or the next reward tier.

A further advantage is that a loyalty programme increases purchase frequency, not just basket size. To make it work, you need a system that recognises the customer, counts their purchases and applies the benefits automatically.

How to add additional sales to your website and online store

In a physical store, a good salesperson suggests an add-on at the right moment. Online, that job falls to the design, the structure and the platform settings. There are five points where an additional offer makes sense.

The product page

This is the place for upselling: a short comparison of versions, with the recommended one clearly highlighted. You can also add a "frequently bought together" block with two or three complementary products.

The cart

In the cart, the customer has already decided, so it is a good spot for a small, inexpensive cross-sell. A free shipping progress bar ("€10 away from free shipping") works well, as long as suitable items that close the gap are shown right next to it.

Checkout

Be careful at checkout. Any distraction can make the customer abandon the purchase. Only one small, relevant addition belongs here, such as gift wrapping, an extended warranty or express delivery, added in one click without leaving the page.

The thank-you page

After paying, the customer is relaxed and satisfied. It is a good moment to offer a perk for the next purchase or a complementary product at a time-limited discount.

Post-purchase email and messages

A few days after the product arrives, you can send a message with usage tips and a recommendation for a complementary product. A message like this feels like service, not advertising.

What each platform offers

• WooCommerce (WordPress). Every product has built-in Upsells and Cross-sells fields, displayed on the product page and in the cart. Plugins let you add bundles and checkout offers.
• Shopify. The official Search & Discovery app lets you set complementary and related products, and the Shopify App Store has many tools for bundles and post-purchase offers.
• Webflow Ecommerce. There is no built-in upsell mechanism, but you can build complementary product blocks with CMS Reference fields and add logic with custom code or an integration.
• Wix. Apps and elements are available for showing related products, and Velo lets you build custom logic.

If you are still planning your store, think about additional sales at the specification stage: which products complement each other, where offers will appear and what data you need to store to trigger them automatically.

Automating additional sales: CRM, messaging and email

Most of the tactics above work better when they are automated. Nobody can remember manually when each customer last bought, and nobody can send a thousand personal messages one by one.

What you need to make it work

• A well-organised customer database. Every order from your website, your point of sale and your phone line should land in one place, with customer details, what they bought and when. Usually this is a CRM system. We cover how to pick one in our guide on how to choose a CRM for your business.
• Clear rules. For example: send a reminder 21 days after a treatment; a customer who hasn't bought for 90 days gets a special offer; anyone who buys product A gets a recommendation for product B a week later.
• Sending channels. Email through an email marketing platform, WhatsApp through an official WhatsApp Business Platform provider, and SMS for short reminders.
• Connections between systems. With APIs and webhooks, and tools such as n8n, Make or Zapier, you can connect your store, CRM and messaging channels without building everything from scratch.

How to build your first automated flow

1. Choose one product or service with an obvious complementary product.

2. Decide when the customer needs that complementary product: right away, after a week or after a month.

3. Write a short message that explains what the customer gains, not just the price.

4. Set up the flow in your automation tool and send it to a small group first.

5. After two weeks, check how many additional orders came in, then improve the message or the timing.

Privacy and data use

Segmenting customers by purchase history means processing personal data. If you sell to customers in the EU, the GDPR applies: you need a lawful basis for processing, you should collect only the data you actually need, store it securely and publish a clear privacy policy on your website. Marketing messages also fall under the ePrivacy rules on consent mentioned above. This is not legal advice; when in doubt, consult a lawyer who specialises in data protection.

How to measure whether additional sales work

Every additional sale offer is an experiment, so you have to measure it. These are the key metrics:

• Average order value. Compare it with a similar period before the change, and remember to account for seasonality and holidays.
• Attach rate. The percentage of orders that included the complementary product you offered.
• Conversion rate. If the basket grows but fewer people complete a purchase, the offer is probably getting in the way. This happens most often when checkout is overloaded with offers.
• Returns and cancellations. Lots of returns of a complementary product suggest customers didn't really need it.
• Repeat purchases. RFM flows and loyalty programmes are measured by how many customers came back and how often.

You can track most of these metrics in Google Analytics 4 with ecommerce events, plus your store platform's own reports. When you change an offer on your site, it is best to run an A/B test: half of your visitors see the new version and half see the old one, so you know the change really made the difference.

Common upselling and cross-selling mistakes

Offering everyone the same thing

A generic offer shown to every customer looks like an ad. An offer based on what the customer has chosen looks like good advice. Even without a sophisticated recommendation engine, you can manually assign complementary products to each category.

Overloading checkout with offers

Pop-ups, carousels and three offers before payment all increase abandonment. At checkout, offer one small thing at most.

Suggesting an add-on that costs too much

An add-on that costs almost as much as the product itself puts people off. Go back to the 25 percent rule and test it against your own data.

Fake "promotions"

A discount on an inflated price or a countdown timer that resets on every visit damages trust, and customers spot these tricks quickly.

Not training your team

In a business with sales or support staff, the team needs to know what to offer, to whom and when, and to understand that the goal is to help the customer. A short script and ready-made examples help more than sales targets.

Not measuring

Without measurement, you cannot tell whether an offer increased revenue or just added noise. Decide in advance what you will check and when.

How RJL Studio helps you increase average order value

At RJL Studio, we build online stores and websites on Webflow, WordPress and Wix, and we plan the points where a complementary offer belongs from the start: the product page, the cart, checkout and the thank-you page. We connect your store to your CRM, messaging channels and email marketing platform, and build automated reminder, segmentation and recommendation flows in n8n, Make or Zapier. We also set up measurement in GA4, so you know exactly how much each offer brings in.

Want a store that sells more to the same customers? Read about our automation and integration services and Webflow website development, or get in touch and we will get back to you.

Frequently asked questions

What is the difference between upselling and cross-selling?

Upselling offers the customer a better or more expensive version of the product they chose, for example a model with more memory. Cross-selling offers an additional product that complements the purchase, for example a phone case. You can use both in the same buying journey, just at different points.

How do you calculate average order value?

Divide total revenue for a period by the number of orders in the same period. It is worth calculating it separately for each channel, such as your website, physical store and messaging orders, and for different customer groups, so you can see where there is the most room for improvement.

Do additional sales work for service businesses too?

Yes. In service businesses, they take the form of packages, an upgrade to a higher service tier, ongoing maintenance or a complementary treatment. A beauty salon, a garage, an accounting firm and a web design studio can all offer existing clients a more complete solution.

How can you offer an extra product without being annoying?

Offer only what is genuinely relevant to what the customer chose, explain what they gain, show no more than three options and make it possible to decline in one click. An offer that solves a problem for the customer feels like service, not pressure.

Do you need a CRM to get started?

Not necessarily. Offers on the product page, in the cart and at checkout can be configured in your store platform itself. A CRM becomes important when you want personal reminders, RFM segmentation and a loyalty programme, in other words when additional sales continue after the first purchase.