Cathoven vs TestGlider (2026): Free or Paid? AI Tools Compared

Short answer: choose Cathoven to understand your English at the linguistic level - its CEFR and Language Hub tools are free with daily limits, while IELTS scoring and 50+ mocks cost $21/week or $67.50/month as of September 2026. Choose TestGlider for fast AI-graded full mocks. Neither replaces targeted per-question-type practice.

Cathoven and TestGlider both wear the "AI IELTS tool" label, which makes them look like rivals. In practice they sit at opposite ends of preparation: one is a microscope, the other is a dress rehearsal.

Cathoven analyses language - yours and the texts you study - with computational-linguistics depth. TestGlider simulates test day and scores it quickly. This comparison walks through the standard criteria, names a winner for each, and then covers what neither tool measures.

What each tool actually is

Cathoven comes from the computational-linguistics world. Its Language Hub offers a widely used free CEFR Checker - paste any text and it grades every word against the A1-C2 scale - alongside tools that profile vocabulary sophistication, grammar complexity, sentence difficulty and readability, plus an IELTS-focused scoring platform.

Teachers use it to level materials; candidates use it to see what their English is actually made of.

TestGlider, built by a test-prep technology company that also covers TOEFL, is a mock-test engine: full-length IELTS practice tests taken under real timing in the browser, with AI grading that returns band estimates across sections within minutes as of 2026, plus study materials around them.

Keep that distinction - analysis versus simulation - in view; it decides every criterion below.

Content quality: TestGlider for practice, Cathoven for analysis

TestGlider's mock tests are its content, and they are the point: full sections, realistic timing, on-screen delivery that mirrors the computer-based test. As of 2026 a paid plan unlocks a library of full-length AI-graded mocks, which is a serious volume of exam rehearsal.

Cathoven's practice content has grown - as of September 2026 its Premium tier lists 50+ full-length mock tests across all four skills, plus diagnostic tests and study plans - but its signature is still its instruments.

The quality shows in the analysis: its CEFR and lexical profiling is more granular than anything else aimed at English learners, trusted by a very large user base including many teachers.

Winner: TestGlider if content means practice material; Cathoven if content means analytical capability. For most candidates preparing for a test date, practice material matters more, so TestGlider takes the criterion overall.

Writing feedback: Cathoven

This is where Cathoven shines. Submit an essay and you get a linguistic X-ray: which CEFR level your vocabulary sits at, how varied your grammar actually is, where your sentence complexity ranks, whether you are repeating B1 words while reaching for a Band 7.

It answers the question "is my language genuinely at the level I think it is?" with data.

TestGlider scores your essays as part of its mocks and returns band estimates with improvement notes quickly. That is useful benchmarking, but the feedback is briefer - it is one component of a full-test product rather than a dedicated writing instrument.

Neither frames feedback primarily in the official band-descriptor language an examiner uses. For criterion-by-criterion grading - Task Response, Coherence, Lexical Resource, Grammar - see our roundup of the best IELTS writing checker tools. Winner: Cathoven, for analytical depth.

Reading and Listening practice: TestGlider

TestGlider gives you the real thing: full Reading and Listening sections under exam timing, scored automatically, inside complete mocks. For pacing, stamina and on-screen navigation practice, it is exactly what the final month needs.

Cathoven can analyse a reading text - tell you its difficulty, profile its vocabulary - which is genuinely useful for choosing study material at the right level - and that analysis is free. Timed IELTS-format Reading and Listening tests exist too, but on Premium; TestGlider's whole product is built around that exam-rehearsal flow.

Winner: TestGlider, comfortably. The caveat for both: a mock test tells you your Reading band, not why you missed question 27. Neither tool names the distractor pattern behind a wrong answer.

Speaking help: TestGlider

TestGlider includes Speaking inside its mock flow with AI scoring, so you rehearse all four skills in one sitting - rare among self-serve tools and valuable for test-day stamina.

Cathoven Premium now AI-scores all three Speaking parts as of September 2026, so this criterion is closer than it was; TestGlider's edge is rehearsing Speaking inside a complete timed mock. Candidates whose weak skill is Speaking should still trial both before paying - our guide to the best IELTS speaking practice websites covers the options.

Winner: TestGlider, narrowly, for full-mock Speaking rehearsal.

Pricing and free access: Cathoven

Cathoven's free tier is generous for analysis: its Language Hub tools - CEFR text analysis, Level Adaptor, Reading Generator and Writing Reviser - are free with daily limits and no card.

IELTS scoring, mocks and the AI tutor are Premium: $21 weekly, $67.50 monthly or $172.80 for three months as of September 2026, plus a pay-by-the-day option. A candidate can get real diagnostic value without paying, but not free IELTS band scores.

TestGlider offers free trial tests, then a paid membership for the full mock library and AI grading. The pricing is reasonable for what a full AI-graded mock costs elsewhere, but ongoing use is a subscription.

Winner: Cathoven on free value. TestGlider wins on paid value if what you need is mocks, since that is what the money buys.

Progress tracking: TestGlider, narrowly

TestGlider keeps your mock history, so you can watch overall and per-section band estimates move test by test. That is genuine longitudinal measurement, at whole-section granularity.

Cathoven tracks the metrics of whatever text you analyse, and its Premium tier adds progress monitoring and a personalised study schedule as of September 2026 - but on the free tools you assemble that picture manually.

Neither tracks the number that most efficiently directs study: your band per question type. Knowing your Reading is 6.5 is a headline; knowing True/False/Not Given is your leak is a plan. Winner: TestGlider, with that asterisk.

So which should you choose?

Choose Cathoven if you are diagnosing - especially if you suspect your vocabulary or grammar is capping your Writing band and you want data instead of a feeling. Teachers preparing IELTS students get even more from it.

Choose TestGlider if you are within four to six weeks of your test and need full-length rehearsal with fast scoring. Weekly benchmark mocks are its sweet spot - see our list of the best IELTS mock test websites for how it compares to the field.

Honestly, they pair well: Cathoven tells you what your English is made of, TestGlider tells you what it scores under exam conditions. What sits between them - daily targeted practice that explains every mistake - is a third job.

How to slot each tool into a preparation timeline

Eight or more weeks out, Cathoven earns its place: run two or three of your essays through its profiling early, and you will know whether your ceiling is linguistic (a B1 vocabulary reaching for Band 7) or strategic (good English, weak exam technique). Those two problems have completely different four-week fixes.

If the diagnosis is linguistic, the prescription is input and vocabulary work - reading at the right CEFR level, which Cathoven can also verify for any text you choose. If the diagnosis is strategic, the prescription is question-type drilling with feedback, which neither tool provides.

From four weeks out, TestGlider takes over the weekend slot: one full mock per week under strict timing, same conditions each time, so the trend is comparable. Resist the urge to mock daily - a full test measures preparation, it is not itself efficient preparation.

In the final week, one last mock three or four days before test day, then stop testing and review your accumulated mistakes instead. Walking in rested beats walking in calibrated.

The third option most people actually pick: IELTSbiz

Full disclosure before this section: IELTSbiz is our own platform, so weigh that as you read. Cathoven and TestGlider are both genuinely good at their jobs; the case below is that most candidates need the job neither does.

Between diagnosis and dress rehearsal sits the daily work: practising specific question types, understanding every wrong answer, and watching per-skill bands move. That is what IELTSbiz is built for.

The practice engine generates unlimited fresh Cambridge-style passages for any of the 11 Reading question types, and every wrong answer comes back with trap-level feedback naming the exact distractor pattern that caught you.

Each session feeds per-question-type band tracking, so your dashboard shows precisely which types are costing marks and whether last week's drilling worked. The AI Writing Checker adds criterion-level essay grading: it quotes the sentence behind every correction, so you can check its feedback against your own essay (how we check our marking).

It is free to start with no card, then from $7.99/month or $50 lifetime - see pricing. It covers all four papers - a full 40-question Reading test, timed Listening, Speaking marked from what you said, and a guided four-skill mock.

The honest limits: it has no bank of dozens of full mocks the way TestGlider and Cathoven Premium do, and its lexical analytics are not as deep as Cathoven's CEFR instruments.

Which is why the realistic stack for a data-minded candidate is: IELTSbiz for daily measured practice, a periodic TestGlider mock for exam conditions, and Cathoven when you want a linguistic deep-dive on your writing.

Diagnose with a microscope, rehearse with a simulator - but improve with an instrument that measures every rep in between.