The short answer
Per page: one main (focus) keyword, plus around three to five closely related keywords and phrases that fit naturally.
Per website: as many as you have useful pages for. A small local business might sensibly target 10 to 30 main keywords across its homepage, service pages, area pages and guides.
The rule that matters most is not a number at all: each page should target one clear search intent, and no two pages should target the same one.
Why one main keyword per page?
Google ranks pages, not websites. Each page needs a clear job. If one page tries to rank for "plumber", "boiler repair", "bathroom fitting" and "drain unblocking", it ends up being a weak match for all of them.
Give each a page of its own and each one becomes the best answer for its search. That's why a well-structured local business site has a separate page for each main service and area.
What are related keywords?
Related (or secondary) keywords are variations and close topics that support your main keyword. For example, a page targeting "boiler repair Milton Keynes" might also naturally include:
- boiler engineer Milton Keynes
- boiler breakdown
- Gas Safe engineer
- combi boiler repair
- emergency boiler repair MK
These help Google understand the topic fully. They also mean the page can rank for dozens of long-tail searches you never targeted directly. A single good page often ranks for 20 or more different searches.
How many times should a keyword appear?
There is no magic percentage. "Keyword density" is an outdated idea, and repeating a phrase over and over (keyword stuffing) now works against you.
Instead, make sure your main keyword appears in the places that matter:
- The page title (the blue link in Google)
- The main heading (H1)
- The first paragraph
- At least one subheading, where it reads naturally
- The page address (URL)
- The meta description
After that, write naturally for your customer. If it reads well out loud, it's usually fine for Google too.
How many keywords for a whole website?
Think in pages rather than keyword counts. A typical small local business site might look like this:
| Page type | Example main keyword | How many |
|---|---|---|
| Homepage | electrician Milton Keynes | 1 |
| Service pages | EV charger installation Milton Keynes | One per main service, often 4 to 10 |
| Area pages | electrician Bletchley | One per town or district you serve |
| Guides and blogs | how much does a rewire cost | One per question your customers ask |
That's how a site grows from ranking for a handful of searches to hundreds, without any one page being overloaded.
Avoid keyword cannibalisation
Keyword cannibalisation happens when two of your own pages target the same keyword. Google can't tell which one to rank, so often neither ranks well. If you have two similar pages, either merge them into one stronger page or give each a clearly different focus.
How to choose the right keywords
- Start with your services and areas. What do you do, and where? That gives your core list.
- Think like your customer. They search "boiler not working", not "heating system diagnostics".
- Check search volume. Tools like Google Keyword Planner or Semrush show roughly how many people search each phrase a month.
- Weigh up competition. A new website will rank faster for specific, local phrases than for broad national ones.
- Match the intent. "Plumber near me" wants a service page. "How to bleed a radiator" wants a guide.
- Look at the questions. The "People also ask" box in Google is a great source of guide topics.
Long-tail keywords are your friend
Long-tail keywords are longer, more specific searches like "same-day boiler repair Newport Pagnell". Each one has fewer searches, but they are easier to rank for and the people searching them are usually ready to buy. For a local business, a site full of well-targeted long-tail pages often brings in more customers than chasing a single big keyword.