Claude Sonnet 4 vs GLM-4.5-Air
Wins 5 of 6 areas
Coding · Reasoning · Facts · Long documents · Following instructions
Wins 0 of 6 areas
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Claude Sonnet 4 is the stronger all-rounder.GLM-4.5-Air is cheaper.
Scores updated · 33 tests both models report · How we compare
Where each one wins
Tests won in each of the six 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.
- CodingWriting and fixing software30Claude Sonnet 43 of 3 tests
- ReasoningHard problems that need careful thinking20Claude Sonnet 42 of 3 tests · 1 tie
- FactsGetting facts right instead of making them up21Claude Sonnet 42 of 3 tests
- Long documentsFinding answers in very long texts10Claude Sonnet 41 of 1 test
- Following instructionsDoing exactly what it is asked10Claude Sonnet 41 of 1 test
- AgentsCarrying out multi-step tasks on its own11Even1 each
Long documents and following instructions 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.
GLM-4.5-Air costs 94% 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 Sonnet 4 pulls ahead
- Avoids making up answers it doesn't knowAA-Omniscience · Non-hallucination+63.8points ahead
- Reasons across sets of long documentsAA-LCR+23.6points ahead
- Follows unfamiliar, precisely checkable instructionsIFBench+17.1points ahead
Where GLM-4.5-Air pulls ahead
- Finds hard-to-locate facts by browsing the webBrowseComp+9.1points ahead
Every test, side by side
All 33 tests both models report. The winning score is in its model's colour; marks a score checked independently.
CodingClaude Sonnet 4
- SWE-bench VerifiedClaude Sonnet 4 by 15.172.757.6+15.1
- Terminal-Bench HardClaude Sonnet 4 by 10.631.120.5+10.6
- SciCodeClaude Sonnet 4 by 9.44030.6+9.4
AgentsEven
- BrowseCompGLM-4.5-Air by 9.112.221.3+9.1
- GDPValClaude Sonnet 4 by 6.79.73+6.7
ReasoningClaude Sonnet 4
- GPQA DiamondClaude Sonnet 4 by 4.477.773.3+4.4
- Humanity's Last ExamClaude Sonnet 4 by 3.710.77+3.7
- CritPttie0.30tie
FactsClaude Sonnet 4
- AA-Omniscience · Non-hallucinationClaude Sonnet 4 by 63.870.97.1+63.8
- AA-Omniscience · AccuracyClaude Sonnet 4 by 6.422.716.3+6.4
- Vectara HHEM hallucination ratelower is betterGLM-4.5-Air by 110.39.3+1
Following instructionsClaude Sonnet 4
- IFBenchClaude Sonnet 4 by 17.154.737.6+17.1
Other results20 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.
- AA-OmniscienceClaude Sonnet 4 by 61.70.2-61.5+61.7
- HarmBenchClaude Sonnet 4 by 41.89856.1+41.8
- AIR-Bench 2024Claude Sonnet 4 by 31.288.357.1+31.2
- τ²-Bench Telecom (AA run)Claude Sonnet 4 by 18.164.646.5+18.1
- Artificial Analysis Coding IndexClaude Sonnet 4 by 13.837.623.8+13.8
- AIME 2025GLM-4.5-Air by 12.870.583.3+12.8
- AA IntelligenceClaude Sonnet 4 by 7.818.911.1+7.8
- vectara_avg_summary_lengthClaude Sonnet 4 by 75.2 rating points145.870.6+75.2 rating
- Terminal-BenchClaude Sonnet 4 by 5.535.530+5.5
- MATH-500 (EM)GLM-4.5-Air by 4.19498.1+4.1
- AA Agentic IndexGLM-4.5-Air by 3.417.621+3.4
- TAU-bench (retail)Claude Sonnet 4 by 2.680.577.9+2.6
- MMLU-ProClaude Sonnet 4 by 2.383.781.4+2.3
- LiveCodeBenchGLM-4.5-Air by 2.268.570.7+2.2
- XSTestGLM-4.5-Air by 296.698.6+2
- simple_safety_testsClaude Sonnet 4 by 110099+1
- vectara_factual_consistencyGLM-4.5-Air by 189.790.7+1
- TAU-bench (airline)tie6060.8tie
- vectara_answer_ratetie98.698.1tie
- anthropic_red_teamtie99.299tie
Questions people ask
Which is better, Claude Sonnet 4 or GLM-4.5-Air?
Claude Sonnet 4 wins five of the six areas where both have results: coding, reasoning, facts, long documents and following instructions. GLM-4.5-Air wins none, but costs 94% less. They are level on agents.
Which is better for coding?
Claude Sonnet 4. It wins 3 of the 3 coding tests both models report; GLM-4.5-Air wins none.
Which is cheaper?
Claude Sonnet 4 costs $3.00 per million input tokens and $15.00 per million output tokens; GLM-4.5-Air costs $0.17 and $0.98. That makes GLM-4.5-Air about 94% cheaper for the same work.
How do you compare the two?
We use the 33 benchmark tests both models have published scores on. The verdict counts the 13 tests in the eight capability areas, and a gap under one point (ten on rating-style scales) counts as a tie. The other 20 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.