The two are evenly matched.Claude Opus 4.1 is better at coding; Qwen3.5 Flash at math.
Scores updated · 8 tests both models report · How we compare
Where each one wins
Tests won in each of the three areas where both have results. Each piece is one test, so a longer bar means more evidence; grey means the two scored within a point of each other.
Coding and math rest on a single test each.
What it costs
Prices per million tokens, roughly 750,000 words. The bars show the cost of a million tokens read plus a million written.
Qwen3.5 Flash costs 99% less for the same work.
The biggest differences
The tests each model wins by the widest margin, up to three each. Scores are out of 100.
Where Claude Opus 4.1 pulls ahead
- Short factual questions, answered correctlySimpleQA Verified+14.5points ahead
Where Qwen3.5 Flash pulls ahead
- Unpublished advanced math problemsFrontierMath Tiers 1-3 (v2)+5.7points ahead
Every test, side by side
All 8 tests both models report. The winning score is in its model's colour; marks a score checked independently.
CodingClaude Opus 4.1
- LMArena · WebDevClaude Opus 4.1 by 152 rating points13901238+152 rating
FactsEven
- SimpleQA VerifiedClaude Opus 4.1 by 14.534.820.3+14.5
- Vectara HHEM hallucination ratelower is betterQwen3.5 Flash by 1.311.810.5+1.3
Other results4 tests, not counted
Tests outside the eight areas. They are not counted above: several are summary scores built from other tests, or the same test under another name.
- vectara_answer_rateQwen3.5 Flash by 7.492.499.8+7.4
- frontiermath_tier_4_v1Claude Opus 4.1 by 4.24.20+4.2
- vectara_avg_summary_lengthClaude Opus 4.1 by 34.1 rating points129.195+34.1 rating
- vectara_factual_consistencyQwen3.5 Flash by 1.388.289.5+1.3
Questions people ask
Which is better, Claude Opus 4.1 or Qwen3.5 Flash?
Claude Opus 4.1 and Qwen3.5 Flash each win one of the three areas where both have results. Claude Opus 4.1 wins coding; Qwen3.5 Flash wins math. Qwen3.5 Flash costs 99% less. They are level on facts.
Which is better for coding?
Claude Opus 4.1. It wins the one coding test both models report.
Which is cheaper?
Claude Opus 4.1 costs $15.00 per million input tokens and $75.00 per million output tokens; Qwen3.5 Flash costs $0.10 and $0.40. That makes Qwen3.5 Flash about 99% cheaper for the same work.
How do you compare the two?
We use the 8 benchmark tests both models have published scores on. The verdict counts the 4 tests in the eight capability areas, and a gap under one point (ten on rating-style scales) counts as a tie. The other 4 are listed but not counted, because several are summary scores or repeat a test. Each score is the one shown on the model's own page.