Facebook advertising: a guide for webshops (2026)

Facebook advertising is called Meta Ads now

You no longer buy ads on Facebook alone. You buy them in Meta Ads Manager, and they're spread automatically across Facebook, Instagram, Messenger and Audience Network. In practice you should rarely pick the platform by hand. The algorithm finds cheaper impressions when it's allowed to move the budget to where they are.

It also means a lot of the advice from 2019 is wrong today. Detailed interest targeting, lots of small ad sets and manual placements were right back then. Today they starve the algorithm of data and make your ads more expensive.

This guide is written for webshops. It starts with what needs to be in place before you spend anything, walks through setting up a campaign and ends with the places where the money most often disappears.

What needs to be in place before you advertise

The order matters more than most people think. Start with the ads and sort out tracking afterwards, and you pay for a learning period in which the algorithm has been looking for the wrong people. That's money you don't get back.

• A Business Manager that owns your page, ad account, pixel and catalogue. If the assets sit on a personal profile, you lose them the day that person changes jobs.
• A Facebook page. Ads on Facebook run in the page's name, and plenty of people click through to it before they trust the ad.
• An ad account with the payment method, currency and time zone set correctly from the start. If the currency or time zone has to change later, Meta makes you create a new account.
• The Meta pixel and the Conversions API, so purchases are measured both in the browser and from the server.
• A verified domain and a product catalogue, if you want to run catalogue ads.

How an account is put together

There are three levels. The campaign sets the objective, and for a webshop that's almost always sales. The ad set sets the budget, audience, placements and the event it optimises for. The ad is the image or video itself, with text and a link.

The most common mistake is building too many ad sets. Meta recommends around 50 optimisation events per ad set per week before delivery is stable and the learning phase ends. A budget split across ten ad sets gives you ten units that all learn too slowly. Fewer ad sets with bigger budgets is almost always better than the other way round.

The budget can sit on the campaign (CBO) or on each ad set (ABO). For a webshop with enough purchases, a campaign budget is the best starting point, because Meta moves the money to where it works. ABO is most useful when you want to test something under controlled conditions.

Choose the objective you actually want to pay for

Meta gives you what you ask for. Choose traffic, and the algorithm finds the people who click the most, and they're rarely the ones who buy. Choose engagement, and you get likes. The campaign objective is really an instruction about who should see the ad.

For a webshop, the objective is sales, with purchase as the optimisation event. If there are too few purchases for an ad set to learn from, you can optimise for an earlier step such as add to cart or initiated checkout for a while. It's a compromise, and it should be treated as one. As soon as there are enough purchases, switch back.

Lead generation, such as bookings for a clinic, follows the same logic. Optimise for the enquiry you actually want, and ideally send the quality back to Meta, so the algorithm learns the difference between a good enquiry and a bad one.

How to set up your first campaign

Once the groundwork is in place, the setup itself doesn't take long. This is the order we use ourselves on a new account.

1. Create a campaign with the Sales objective, and turn on campaign budget.
2. Choose your pixel or dataset, and Purchase as the optimisation event.
3. Set a daily budget that can carry the purchases the learning phase needs. The maths is in our article on what Facebook advertising costs.
4. Keep the audience broad: country, possibly age, and otherwise let Advantage+ audience do the work. Exclude existing customers if you want to see new customers on their own.
5. Leave placements on Advantage+ placements, so Meta can use both Facebook and Instagram.
6. Upload a few ads with a different angle each, not five versions of the same image. Deliver the creative in 4:5 for feed and 9:16 for Reels and Stories.
7. Check the preview for every placement, and fix any cropping before you publish.
8. Let the campaign run for a week without touching it. Big changes to budget, audience or ads can send the ad set back into the learning phase.

Audiences: broad beats narrow

Denmark is a small market. An interest audience of a few hundred thousand people reaches the same people again and again, and the price goes up as frequency does. Broad targeting with strong creative almost always beats narrow targeting with weak creative.

That's because the ad itself has become the targeting. The algorithm sees who stops, clicks and buys, and finds more people like them. An ad about running shoes finds runners without you asking it to.

Custom audiences still have a role. Customer lists, site visitors and people who've watched your videos are used to exclude existing customers or to give Meta a hint about who you're looking for. As a starting point for finding new customers, broad targeting is the most effective option today.

Ad formats and what they need

Meta scales the creative itself, so the aspect ratio matters more than the pixel dimensions. Three ratios cover almost everything: 1:1 for feed, 4:5 for feed on mobile and 9:16 for Reels and Stories. If you only make one, make it 4:5. It takes up the most space in the mobile feed without being cropped.

• Single image: the quickest to produce and the easiest way to test messages.
• Video: vertical for Reels and Stories. The first few seconds decide whether anyone sticks around, and the video has to make sense without sound.
• Carousel: several cards in the same ad. Good for several products or a story told in steps. The first card decides whether anyone swipes on.
• Catalogue ads: the images are pulled from the product feed and shown based on what people have looked at in the shop. The quality depends on the feed.

Tracking decides the rest

Meta can only optimise for what it can see. With only a browser-based pixel, you lose part of your conversions to cookie blocking and iOS restrictions. What you lose is more than reporting. It's the signal the algorithm learns from.

That's why the Conversions API belongs in the basic setup. Events are sent from server to server and matched with the pixel data, so the same purchase isn't counted twice. If you also send order value or contribution margin, Meta optimises for something that looks like your bottom line rather than the number of orders.

Check event match quality in Events Manager once the setup is done. The more customer information you send in hashed form, the more purchases Meta can tie to the right ads.

How to read the results

Ads Manager shows a lot of numbers, and most of them are for troubleshooting. The number that steers is cost per purchase compared with what an order leaves in contribution margin. If the cost is lower, the budget can grow. If it's higher, something has to change before you spend more.

Below that sit the operating numbers. CPM tells you what it costs to reach people. Click-through rate tells you whether the ad gets people to act. Frequency tells you how many times the same people have seen it. If frequency rises while click-through rate falls, the ad is burning out.

Meta's own numbers aren't the whole truth either. The platform credits itself with sales that would have happened without the ad. So keep an eye on the ratio between total revenue and total marketing spend (MER) in the shop, and use Ads Manager to understand what moves it.

Where the money usually goes

The first place is creative fatigue. Frequency creeps up, click-through rate falls, and cost per purchase rises slowly enough that nobody notices in time. It's rarely the audience that's burnt out. It's the ad people have stopped seeing.

The second is scaling up too fast. Double the budget overnight and you reset the learning phase and pay for it twice. Steps of 20-30% a few days apart cost less and keep results stable.

The rest are mistakes we see again and again when we take over an account:

• Posts boosted from the page instead of campaigns built in Ads Manager. A boost gives you fewer choices of objective, targeting and measurement.
• Ads judged after two days. Delivery swings most at the start, and the one that looks worst after a day can end up the best.
• Campaigns optimising for traffic or engagement when the goal is sales.
• The same ads running for months with no new creative behind them.
• Meta's own numbers standing alone as the verdict on whether the ads make money.

What it costs

You set the budget yourself, and the price per impression, click and purchase is set in an auction. What it has cost in practice, with numbers from the webshops we run Meta for, is in the article on what Facebook advertising costs.

The short version is that cost per purchase is decided more by order value and by how many customers buy again than by the price of an impression. That's why your own maths matters more than other people's numbers.