Build 1,000 Long-Tail Keywords in 30 Seconds (Then Check Which Ones Are Worth It)

If you’ve ever built a long-tail keyword list by hand, you know the drill. You open a spreadsheet, type “best running shoes,” then “cheap running shoes,” then “running shoes for beginners,” then you swap in “sneakers” and do it all again, then you add a city name to half of them because you’re doing local SEO too. An hour later you have 80 rows and a headache, and you still haven’t checked whether any of them are worth targeting.

That’s manual keyword combining, and it’s slow, repetitive, and exactly the kind of task a computer does better than a human. A modifier list, a product list, and a “for” key crossed against every combination takes a script milliseconds. It takes you an hour, and you’ll still miss combinations or introduce typos along the way.

This post covers how to generate those combinations for free in seconds, what they’re actually good for, and the part most “keyword generator” articles skip entirely: raw combinations are not keywords. They’re just word soup until you check whether anyone searches for them. We’ll cover that too.

What a keyword mixer actually does

A keyword mixer (also called a keyword combiner) takes two or more lists of words and outputs the Cartesian product, meaning every possible pairing across all lists, one per line.

Say you have:

List A (modifiers): buy, cheap, best List B (products): running shoes, sneakers

Cross those two lists and you get:

buy running shoes
buy sneakers
cheap running shoes
cheap sneakers
best running shoes
best sneakers

Six combinations from two short lists. Add a third list, say three city names, and you jump to 18 combinations without typing a single additional phrase yourself. Add a fourth list and the count multiplies again. This is the entire value proposition: the tool does the multiplication, you just supply the lists.

The math scales fast. Three modifiers times five products times four cities is 60 phrases from three short lists you can type in under a minute. That’s the appeal, and also, as we’ll get to, the trap if you stop there.

Do it free with the Keyword Mixer

You don’t need a paid rank tracker or a $99/month suite to generate combinations. Our Keyword Mixer does exactly this, free, in the browser, with no signup:

• Paste up to four separate lists (modifiers, products, locations, whatever you need)
• Choose your separator: space, dash, underscore, comma, or none
• Automatic deduping so you’re not staring at the same phrase twice
• Sort output alphabetically or leave it in generation order
• Export straight to CSV for your keyword tool, ad platform, or content calendar

It runs entirely client-side, so nothing you paste gets sent anywhere. Paste your lists, hit generate, and you have your full combination set in under a second, no matter how large. That part of the workflow should never cost you money or take more than a minute of your time. If a tool wants you to pay or sign up just to multiply two lists together, skip it.

Real use cases

Combination generation isn’t just an SEO parlor trick. It’s genuinely useful across a few different workflows:

Local SEO. Cross a service list (plumber, electrician, roofer) against a city or neighborhood list to build out location pages or track rankings across every service area a business covers. This is the single most common use case we see for this kind of tool.

PPC ad groups. Google Ads and Bing rewards tightly themed ad groups. Mixing modifiers against products gives you a fast starting point for ad group structure before you touch match types or bids.

Ecommerce product pages and category filters. Attribute combinations like “waterproof hiking boots for men” or “size 10 waterproof hiking boots” come straight out of crossing size, material, and use-case lists. Useful for both on-page targeting and faceted navigation planning.

Programmatic SEO and content briefs. If you’re building out a “[service] in [city]” or “[tool] vs [tool]” page template, the combination list is your production queue. Generate it once, then run it through a validation step (more on that below) before anyone writes a word.

In every one of these cases, the mixer does the same job: turn two or three short lists into the full set of combinations so you’re not manually assembling them one at a time.

The catch: combinations are not keywords

Here’s the part that gets glossed over in most “free keyword generator” posts, and it matters more than the generation step itself.

A Cartesian product doesn’t know anything about how people actually search. It will happily hand you “best sneakers for elderly cats,” “cheap running shoes Antarctica,” and a hundred other phrases nobody has typed into Google, ever. Some fraction of your generated list will have real, meaningful search volume. Another fraction will have zero volume, and a third fraction will look reasonable but carry a keyword difficulty that makes ranking a multi-year project instead of a realistic goal.

Publishing pages or building ad groups off raw combinations without checking this is how you end up with a site full of zero-traffic pages, or an ad account burning budget on phrases nobody searches for. The generation step is free and instant. The validation step is where the actual research happens, and skipping it is the single biggest mistake people make with these tools.

You don’t need Ahrefs at $99/month to do this validation, though. For checking volume and difficulty on a list of a few hundred combinations, a cheap dedicated keyword tool does the job for a fraction of the price.

KeySearch is the one we’d start with. It runs $17/month, has a bulk difficulty checker that handles up to 50 keywords at once (so you can batch through your generated list instead of checking one phrase at a time), and gives you volume and difficulty scores side by side. It won’t match Ahrefs’ database depth or international coverage, and you shouldn’t expect it to at this price. But for filtering a pile of raw combinations down to the ones actually worth targeting, it’s more than enough.

Mangools (formerly KWFinder) is the other option worth a look, especially if you want a cleaner interface and don’t mind paying slightly more. Both tools solve the same problem: they tell you which of your generated combinations have real demand and a realistic difficulty score, without the enterprise price tag. Neither replaces Ahrefs for deep backlink work or large-scale agency research, and we’re not pretending they do. For a one-off validation pass on a mixer’s output, though, either is the right tool for the job, not the $99-a-month one.

The full free-first workflow

Put it together and the process looks like this:

1. Mix. Build your lists (modifiers, products, locations, whatever fits your use case) and run them through the Keyword Mixer to generate every combination. Free, instant, no signup.
2. Dedupe and export. The mixer handles deduping automatically. Export the clean list to CSV.
3. Check the competition first. Before you spend credits checking volume, run the domains currently ranking for your seed terms through the Bulk Ahrefs DR Checker. Paste up to 25 domains and see their Domain Rating at once, free, no signup. If the top results for your seed terms are all sitting at DR 70+, a lot of your generated combinations under that umbrella are going to be a hard climb regardless of volume. This step tells you where it’s even worth spending validation credits.
4. Validate volume and difficulty. Take the combinations that survived the competition check and run them through KeySearch or Mangools to get real search volume and difficulty numbers. This is where you cut a 200-line list down to the 20-30 phrases actually worth writing content for or building ad groups around.
5. Build. Only now do you write the page, build the ad group, or add the row to your content calendar.

Skip step 3 or step 4 and you’re publishing blind. The mixing step is free because multiplying two lists together is trivial. The validation steps cost a little because they require actual search data, and that data is what turns a word-combination exercise into an SEO or PPC strategy.

FAQ

Is the Keyword Mixer really free, no signup? Yes. It runs entirely in your browser and doesn’t require an account. Paste your lists, generate, export. Nothing you enter is sent to a server.

How many keywords can I generate at once? The tool supports up to four input lists, and the output size is simply the product of each list’s length. Two lists of 10 and 5 gives you 50 combinations; four lists of 10 gives you 10,000. There’s no artificial cap on the free tool, but past a few thousand rows you’ll want to validate a sample before committing to the full set.

Do I need to check every single combination for volume? No, and you probably shouldn’t try. Use the DR checker to see which seed terms are realistically competitive, then run only the surviving combinations through a volume checker. That two-stage filter saves you both time and tool credits.

What’s the difference between KeySearch and Mangools for this? Both give you volume and keyword difficulty at a fraction of Ahrefs’ price. KeySearch’s bulk difficulty checker is convenient for running through a mixer’s output in batches. Mangools has a cleaner interface if you’re checking keywords less frequently. Neither has Ahrefs-level database depth, but for validating a generated combination list, that depth isn’t what you’re paying for anyway.

Can I use this for PPC, not just SEO? Yes. The combination step works identically for building Google Ads or Bing ad groups. You still want to sanity-check search volume before you build out ad groups around zero-volume phrases, since low or no volume means your ads simply won’t show.