TestGlider vs BAND9AI IELTS: Mock Tests vs Criterion AI
Platform comparison · May 2026
Direct answer
TestGlider simulates full IELTS mocks with automated section scores and estimated productive-skill bands. BAND9AI diagnoses which rubric descriptor caps your Writing and Speaking on your own submissions. Use TestGlider for timed volume and pacing habits; use BAND9AI when mock overall bands stall and you need criterion-level cause, not another headline number.
Two different jobs
TestGlider optimizes test-day simulation. BAND9AI optimizes rubric leaks on submitted work. Neither replaces the other when your bottleneck is undiagnosed Task Response or false Speaking confidence.
TestGlider strength Full timed mocks and section scores
BAND9AI strength Per-criterion Writing and Speaking bands
Best together Mock weekly; criterion check on weakest skill
Side-by-side comparison
| Dimension | TestGlider | BAND9AI |
|---|---|---|
| Primary output | Section scores + overall estimate | Criterion bands + leak notes |
| Writing depth | Holistic band estimate | TR/TA, CC, LR, GRA split |
| Speaking | Often holistic or transcript-based | Audio criterion feedback |
| Best for | Volume and timing habit | Mid-band plateau diagnosis |
Combined workflow
- Take a blind TestGlider mock under real timing.
- Note which section drags—not only overall.
- Submit weakest Writing/Speaking for criterion AI.
- Fix one descriptor; retest in 7–10 days.
Key takeaways
- TestGlider = mocks and pacing; BAND9AI = why your band stalls.
- Do not treat either overall band as official.
- Pair mock volume with rubric diagnosis.
- Validate with human mocks before exam fees.
FAQ
No. Mocks show outcome; criterion AI shows which descriptor caps your score.
Mocks estimate holistically; BAND9AI splits criteria—use both and validate with human review.
Yes for regular practice: weekly mocks plus criterion checks on your weakest productive skill.
Compare mock scores with criterion-level truth.
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