What’s the best truly free keyword research tool online?

General
1

I’m trying to grow a small niche website and I’m struggling to find a reliable, truly free keyword research tool for SEO. Most tools I try either limit searches heavily, hide keyword volumes, or lock the best features behind a paywall. I need suggestions for free keyword tools that show search volume, difficulty, and related keyword ideas so I can plan content without paying for an expensive subscription.

2

Short answer from someone cheap and stubborn: use a combo, not one “magic” free tool.

Best stack I use for niche sites without paying:

  1. Google Keyword Planner
    • Create a free Google Ads account
    • Use “Discover new keywords”
    • Switch match type to “Exact”
    • Sort by Avg. monthly searches
    • Use “Top of page bid (low range)” as a proxy for intent and value
    • Export to sheet and filter junk
    Volumes are grouped, but still good enough for prioritizing.

  2. Google Search Console
    • Only works once your site has some content
    • Go to Performance → Search results
    • Sort by impressions
    • Find queries where you rank 10 to 30 with decent impressions
    • Turn those into new articles or improve existing ones
    This is the best data you will get about your own pages.

  3. Google autosuggest stack
    • main query → autocomplete
    • “people also ask”
    • “related searches” at bottom
    Paste all of these into a sheet.
    Use them for subheadings and FAQ sections.
    You will see long tails your competitors skip.

  4. Free Keyword Surfer (Chrome extension)
    • Shows rough volume directly in Google results
    • Also gives related keywords in the sidebar
    Volumes are not perfect, but close enough for small sites.

  5. Ahrefs free tools
    • Ahrefs Free Keyword Generator
    • 100 keyword ideas per search for Google, YouTube, etc
    • Shows KD for 10 terms per search
    Use it to sanity check difficulty and find extra phrasing.

How I would work on a niche site with zero budget:

Step 1
Seed list from my own brain + competitors.
Find 10 to 20 seed keywords about the niche.

Step 2
Run each seed through Keyword Planner.
Export 500 to 2000 keywords.
Clean out brands, irrelevant countries, etc.

Step 3
Use free Ahrefs Keyword Generator for each main topic.
Take the low KD and long phrases.
Add to the sheet.

Step 4
Use Keyword Surfer and Google autosuggest on the top 20 targets.
Add the long tails and questions as “supporting” topics.

Step 5
Prioritize by combo of:
• Search volume range
• CPC (if high, more intent)
• SERP check. Look for weak results, forums, Quora, small blogs

No single truly free tool gives perfect volume.
So treat numbers as directional, then look at the SERPs with your own eyes.

If you want only one tool and nothing else, Keyword Planner plus autosuggest is the closest you get to “best free”.
Everything else is about filling gaps and cross checking.

3

Honestly, the “best truly free keyword tool” is kinda a trick question. The second a tool is accurate, it becomes paid or nerfed. @codecrafter already nailed the multi‑tool stack idea, so I’ll throw in stuff that isn’t just rehashing Google + Ahrefs.

If I had to pick ONE “tool-like thing” that’s closest to a free secret weapon for niche sites, it’s actually Bing + Google combined, used in a slightly weird way:

1. Bing Webmaster Tools → hidden gem

Nobody talks about this enough.

  1. Add & verify your site in Bing Webmaster Tools
  2. Go to Search Performance
  3. Filter by:
    • Impressions > 0
    • Position > ~5
  4. Export queries

What you get:

  • Queries that already show your site, often with less competition than Google
  • A bunch of long-tails that never show in Keyword Planner
  • Actual click + impression data, which is more honest than most third-party “volume” numbers

Then:

  • Take those queries, plug them into Google, and look at the SERP softness
    If results are full of forums, thin listicles, or random Pinterest garbage, that’s a great niche article opportunity.

This complements what @codecrafter said about Search Console, but Bing often surfaces slightly different terms with weaker competition.

2. Reddit + niche forums as a “keyword engine”

Not a tool, but this is where a lot of the real long-tails hide:

  1. Go to Reddit and search your main topic
    Example: site:reddit.com 'cold plunge', or just use Reddit search
  2. Sort by Top & All time
  3. Look for:
    • Repeated question phrasing
    • Titles like “Is X worth it?” “How do you Y?” “What’s the best Z under $50?”
  4. Copy recurring phrases into a sheet

Then:

  • Turn those into content formats:
    • “X vs Y”
    • “Best X for Y situation”
    • “How to X without Y problem”

Most keyword tools suck at those pragmatic “real user” long-tails, but they’re search magnets.

You can do the same with:

  • Niche forums
  • Facebook groups (search bar inside the group)
  • Amazon reviews for products in your niche

Treat repeated phrases like volume signals, even if no tool shows “real” numbers.

3. Free trials & churn strategy

This is slightly scummy but effective if you’re broke:

  • Sign up for 7‑day or 14‑day trials on tools like Semrush, Mangools, Serpstat etc
  • Spend a single weekend:
    • Dump all your seed ideas in
    • Export everything
    • Build one monster spreadsheet
  • Cancel before billing

You’re not using the tool “ongoing,” but you get:

  • Solid initial map of your niche
  • Keyword difficulty estimates
  • Enough data to keep you busy for months

Not as clean as a perpetual “free tool,” but in practice it’s more useful than staring at crippled free dashboards forever.

4. SERP-based difficulty instead of tool metrics

I slightly disagree with relying too much on any “KD” or CPC as a beginner. They’re helpful, but for tiny niche sites, the SERP strength matters more:

When you check a keyword manually, ask:

  • Are there big brands on top?
  • Any forum threads ranking high?
  • Any very short, weak articles?
  • Are there very old pages with low-quality content?

If you see:

  • Forums like Reddit, Quora
  • Thin affiliate listicles
  • Outdated posts from 2015

That keyword is often beatable, even if tools say “medium” difficulty.

This lets you:

  • Use any free volume source as just a rough filter
  • Let your eyes judge the real opportunity

5. “Poor man’s volume validation”

When a keyword has no visible volume or tools all disagree, try to cross-check like this:

  1. Plug the keyword into Google Trends (exact phrase)

    • Compare it to a similar keyword with known volume from Keyword Planner
    • Use the relative line height to gauge if it’s “tiny,” “decent,” or “spicy”

  2. Look at:

    • Autosuggest depth (how many variations pop up when you type more letters)
    • People Also Ask count and specificity
    • Are there multiple pages of hyper-focused results?

If there’s rich SERP decoration and lots of closely related queries, there is some decent search demand, even if the number is “10” in tools.

So, what’s “best” if you just want one thing?

If you absolutely force me to name a single “tool” and not a stack:

  • Bing Webmaster Tools for data on your own site
    plus
  • Google SERP (autosuggest, PAA, related searches) for ideation

Those two together are:

  • Free
  • First-party-ish
  • Not as heavily nerfed as the popular third-party keyword dashboards

Everything else is just ways to slice and validate the ideas they give you.

You won’t get perfect numbers, but for a small niche site, you don’t need perfect. You need:

  • Obvious low‑competition spots
  • Real problems people ask about
  • Consistent publishing on those topics

The “perfect free keyword volume tool” doesn’t exist, and honestly chasing it is how a lot of people avoid actually writing.