Meta descriptions do not affect rankings, and Google rewrites most of them anyway.

What it is actually for

A meta description is a suggestion to the search engine for the snippet under your title in the results. That is the whole job. It does not feed ranking, Google has confirmed as much for years, and the words in it are not read as a relevance signal. Its only influence is on whether a person who already sees your result decides to click it, which matters, but is a different lever from ranking and a much smaller one than the effort spent on it implies.

So the correct mental model is not "SEO text" but "ad copy for a listing you did not pay for". You are writing for the human scanning a page of results, not for the algorithm deciding the order. That reframes what a good one looks like: it earns the click by being specific about what the page delivers, rather than stuffing in the keyword the page already ranks for.

Why Google rewrites most of them

Here is the part that deflates the busywork. Google rewrites the snippet for the majority of results, because it generates a description tailored to the specific query rather than showing your generic one. Someone searching a long specific phrase gets a snippet pulled from the passage of your page that matches it, which is often more compelling than anything you would have written blind. Your carefully composed 155 characters are frequently never shown at all.

That does not make the tag worthless, but it does change the maths. Writing a bespoke description for every URL on a large site, most of which target long-tail queries Google will answer with its own snippet anyway, is effort with almost no return. It is the same misallocation as writing a page for every keyword: activity that looks thorough and produces very little.

Length, and the pixel that actually cuts it

When you do write one, the character-count advice is slightly wrong too. Google truncates the snippet by pixel width, not character count, so a line of wide capitals is cut far sooner than the same number of narrow letters. That is why we built a length checker that measures in pixels and shows where the text is likely to cut on desktop and mobile, rather than counting to 155 and hoping. It runs in the browser and transmits nothing, and it exists precisely because the standard rule of thumb quietly gives wrong answers on capital-heavy or punctuation-heavy copy.

The broader point is that even the technical detail here serves the click, not the ranking. You are keeping the important part of the sentence inside the visible box so a human reads a complete thought, which is an on-page presentation decision rather than a relevance one.

The general lesson

A field full of checklists rewards things that are easy to check over things that are hard to judge, and the meta description is the perfect example: every page either has one or does not, so it gets flagged, counted and fussed over out of all proportion to what it does. Write good descriptions for the pages whose clicks you are actually fighting for, let the rest go, and put the reclaimed hours into the levers that move the ranking the description never touched.