Banner advertising means paying for image or animated ads that appear on websites and apps, usually in boxes along the top, side or middle of a page. They are also called display ads. Most small businesses buy them through the Google Display Network, which reaches millions of sites, apps, YouTube and Gmail, but you can also buy them programmatically or directly from a website owner.

Banners are cheap to show and good at keeping your brand in front of people, especially those who have already visited your website. They are poor at persuading cold audiences to buy straight away. This guide covers where banners appear, the standard sizes, what they cost and how to make them pay.

Banners follow people around the web

Search ads appear when someone types a query into Google. Banner ads work the other way round. They appear while people are reading the news, checking the weather, watching a video or playing a game on their phone. Nobody is looking for you at that moment, so the job of a banner is to catch the eye and plant a seed.

That makes display advertising a different tool from search. It is closer to a poster than a shop sign. Used well, it builds familiarity so that when someone is ready to buy, your name is the one they remember.

Three ways to buy banner ads

Google Display Network

This is where most small businesses start. You set up a Display campaign in Google Ads, choose who you want to reach, upload your ads and set a budget. Google places them across millions of partner websites and apps, plus YouTube and Gmail. You can target by interests, demographics, topics, specific websites or your own website visitors.

You can either upload finished banners in each size or use responsive display ads, where you give Google images, logos, headlines and descriptions and it builds the ads to fit each space. Most campaigns benefit from a mix of both.

Programmatic

Programmatic simply means buying ad space automatically through software called a demand side platform, or DSP. It gives access to more inventory than Google alone, including premium publishers and connected TV, with detailed targeting. The trade off is that most DSPs have minimum spends and need specialist management, so it suits bigger budgets.

Direct deals

You can also go straight to a website and buy space, for example a banner on a local news site, a trade association’s homepage or an industry newsletter. Pricing is usually a flat monthly fee or a cost per 1,000 impressions. Direct deals give you a guaranteed spot in front of a very specific audience, which can work well for local and niche businesses.

Standard banner ad sizes

Most websites build their ad spaces around a set of standard sizes developed by the IAB, the industry body for online advertising. If you design the top five in this list, you will cover the majority of inventory.

Size (pixels)	Common name	Where it usually appears
300 x 250	Medium rectangle (MPU)	Within or beside content, desktop and mobile
728 x 90	Leaderboard	Top of the page on desktop
320 x 50	Mobile banner	Top or bottom of mobile pages and apps
300 x 600	Half page	Sidebar on desktop
160 x 600	Wide skyscraper	Sidebar on desktop
336 x 280	Large rectangle	Within content
970 x 250	Billboard	Top of the page on desktop
970 x 90	Large leaderboard	Top of the page on desktop
320 x 100	Large mobile banner	Mobile pages and apps
468 x 60	Banner	Older sites, headers and footers

Google’s file requirements

For banners uploaded to Google Ads, the main rules according to Google’s display ad specifications are:

• File types: GIF, JPG or PNG.
• Maximum file size: 150 KB per image, which is small, so compress carefully.
• Animation: 30 seconds or less. It can loop, but must stop after 30 seconds, and the frame rate must be slower than 5 frames per second.
• HTML5 banners: up to 600 KB as a zip file, but only for accounts that meet Google’s eligibility rules on spend and history.

For responsive display ads, Google recommends a wide 1.91:1 image at 1200 x 628 pixels and a square image at 1200 x 1200 pixels, plus your logo, short headlines of up to 30 characters, a long headline of up to 90 characters and descriptions of up to 90 characters.

What banner advertising costs

Display is one of the cheapest forms of paid advertising per impression. Costs depend on targeting, competition, season and ad quality, so treat these UK ranges as a rough guide rather than a quote.

How you pay	Typical UK range	Notes
CPM (per 1,000 impressions)	Around £1 to £5 on Google Display	Higher for tightly targeted or premium audiences
CPC (per click)	Often well under £1	Usually much cheaper than search clicks
Programmatic CPM	Roughly £3 to £15 or more	Plus platform fees and minimum spends
Direct deals	Anything from tens to thousands of pounds a month	Depends entirely on the site’s traffic and audience

A useful starting budget on Google Display for a small business is around £5 to £20 a day, especially for retargeting. Click through rates on banners are low, often well below 1%, so judge display on reach, conversions and the lift it gives your other channels rather than clicks alone.

When banners work and when they do not

Where they earn their keep

• Retargeting. Showing ads to people who have already visited your website is the single best use of display for most small businesses.
• Brand awareness at low cost. If you need lots of local people to recognise your name, display reaches them cheaply.
• Launches and events. A new shop, product or promotion with a clear date and a clear offer.
• Visual products. Fashion, food, homes, holidays and anything people want to look at.
• Niche placements. A direct deal on a site your exact customers read every week.

Where they struggle

• Cold selling of complex services. Nobody books an accountant from a banner seen while reading the football scores.
• Tiny budgets spread too wide. £5 a day across the whole UK achieves very little.
• Poor placement control. Left unchecked, ads can end up in low quality apps and games. Review where your ads show and exclude the poor performers.
• Ad blockers and banner blindness. Many people skip past anything that looks like an ad, which is why design matters.

Make your banners worth looking at

1. One message per banner. A single offer or idea. You have about a second.
2. Logo clearly visible so even people who do not click remember who you are.
3. A clear call to action button such as “Book now” or “Shop the sale”.
4. Readable text at small sizes. Test your 320 x 50 on a real phone.
5. Strong contrast and brand colours so the ad stands out on busy pages.
6. Keep animation simple and make sure the final frame works on its own, as that is what many people will see.
7. Match the landing page to the banner so people feel they have arrived in the right place.
8. Test two or three versions and keep the winner.

Setting up retargeting

Retargeting, which Google now calls “your data segments”, works by adding the Google tag to your website so it can build lists of visitors. You can then show banners to people who viewed a product, abandoned a basket or read a service page but did not get in touch. Lists need to reach a minimum size before ads will serve, so turn the tag on well before you plan to launch. Set a frequency cap so the same person is not followed around the internet all week, as that does more harm than good.

Display works best alongside search, Shopping and YouTube rather than on its own, which is how our Google Ads management approaches it for clients.

Related reading: How to Advertise on Google: A Practical Guide for Businesses Ready to Make It Work and PPC Competitor Analysis: How to Find and Use Your Competitors’ Keywords.

Frequently asked questions

What is the difference between banner ads and display ads?

In everyday use they mean the same thing. Display advertising is the wider term and can include responsive ads, native ads and video, while banner usually means a fixed size image ad.

What is the most common banner ad size?

The 300 x 250 medium rectangle is the most widely available, followed by the 728 x 90 leaderboard, 320 x 50 mobile banner and 300 x 600 half page.

Are banner ads worth it for small businesses?

Usually yes for retargeting and local awareness, and usually no as the only channel for winning cold customers. Start with retargeting and build from there.

How big can a Google banner ad file be?

Uploaded image ads on Google Ads can be up to 150 KB in GIF, JPG or PNG format. HTML5 ads can be up to 600 KB for eligible accounts.

Put your banners in front of the right people

Display advertising rewards good targeting, good design and steady testing. If you would like help planning, designing and managing banner and retargeting campaigns, take a look at our Google Ads and PPC service, then get in touch with Delivered Social for an honest conversation about what display could do for your business.