Do meta descriptions affect rankings?

No. Google has said that it doesn’t use the meta description as a ranking signal, so rewriting one won’t move a page up or down. A meta description can change whether someone clicks. It’s the short summary a page offers for display under its title in search results, and when Google uses it, it’s your chance to tell a searcher why your result is the right one.

What a meta description is

It’s a line in a page’s HTML, not visible on the page itself, that summarizes the page for search engines to show. In the results, the block of text under the headline is called the snippet. The meta description is your suggestion for that snippet. It’s only a suggestion, because Google decides what to show.

Google often writes its own snippet

Frequently, the snippet shown is text Google has taken from the page, and the meta description goes unused. Google’s stated aim is to show the part of the page that best matches what the person searched, so one page can show different snippets for different searches. A description is more likely to be passed over when it’s missing, very short, copied across many pages, or silent on what the searcher asked about.

This is no reason to skip descriptions. For the main search a page is built for, a well-matched description has a fair chance of being the text shown. The alternative is letting Google pick a passage from your page, and it sometimes picks an awkward one.

How to write one that earns the click

Say what the page offers, where, and what to do next, in one or two plain sentences.

• Name the service and the place in the words a customer uses. Google may bold words in a snippet that match the search.
• Give one concrete reason to choose you that is true and that the page backs up.
• End with the next step, such as calling for an estimate.
• Write a different one for every page. Duplicates tell the searcher nothing.
• Aim for roughly 150 characters as a guide. Google cuts snippets by the space they take on screen, which differs between phones and computers and changes over time, so put the important part first.

A hypothetical example for a service page: “Water heater repair and replacement in La Mesa by licensed plumbers. Tank and tankless. Call for an estimate.” It names the service and the place, then says what to do. Every claim in it would need to be true of the company using it.

Whether clicks then help rankings

Nobody outside Google can say for certain. Whether and how Google uses clicks in ranking has been argued over for years, and Google’s public statements haven’t settled it. I wouldn’t write descriptions in the hope of an indirect ranking gain.

The direct gain is enough. If you already appear on the first page, more of the people who see your result choosing it means more visits from the same position. Google Search Console reports this as click-through rate (clicks divided by impressions) for each page and each search, so you can measure the effect of a rewritten description instead of assuming it.

Where descriptions sit in the order of work

Meta descriptions come after the things that do affect ranking. If a page targets the wrong search, has a vague title or says little of use, a polished description won’t rescue it. I’d fix those first, starting with the title tag, and then write descriptions for the pages that already get impressions, where a better click rate shows up soonest. Both jobs are part of on-page SEO.

On a site with hundreds of pages, hand-writing every description is rarely the best use of time. Write them for the homepage, the service pages and the area pages, and check the rest are at least not duplicated.

One related tag can be ignored entirely. Google has said for many years that it doesn’t use the meta keywords tag in web ranking, so filling it in achieves nothing.