GLM-5.3-Flash vs Claude Sonnet 5.5
Wins 1 of 8 areas
Images and charts
Wins 7 of 8 areas
Coding · Agents · Reasoning · Facts · Math · Long documents · Following instructions
Claude Sonnet 5.5 is the stronger all-rounder.GLM-5.3-Flash is cheaper and better at images and charts.
Scores updated · 31 tests both models report · How we compare
Where each one wins
Tests won in each of the eight areas we test. Each piece is one test, so a longer bar means more evidence; grey means the two scored within a point of each other.
- ReasoningHard problems that need careful thinking04Claude Sonnet 5.54 of 4 tests
- CodingWriting and fixing software03Claude Sonnet 5.53 of 4 tests · 1 tie
- MathCompetition and research-level math03Claude Sonnet 5.53 of 3 tests
- AgentsCarrying out multi-step tasks on its own02Claude Sonnet 5.52 of 2 tests
- FactsGetting facts right instead of making them up12Claude Sonnet 5.52 of 3 tests
- Long documentsFinding answers in very long texts01Claude Sonnet 5.51 of 1 test
- Following instructionsDoing exactly what it is asked01Claude Sonnet 5.51 of 1 test
- Images and chartsUnderstanding pictures, charts and video10GLM-5.3-Flash1 of 1 test
Images and charts, 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-5.3-Flash costs 95% 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 5.5 pulls ahead
- Extremely hard research-level math problemsFrontierMath Tier 4+63.4points ahead
- Unpublished advanced math problemsFrontierMath Tiers 1-3 (v2)+33points ahead
- Complex command-line tasks across many fieldsTerminal-Bench 4.0+30.8points ahead
Where GLM-5.3-Flash pulls ahead
- Avoids making up answers it doesn't knowAA-Omniscience · Non-hallucination+19.4points ahead
Every test, side by side
All 31 tests both models report. The winning score is in its model's colour; marks a score checked independently.
CodingClaude Sonnet 5.5
- LMArena · WebDevClaude Sonnet 5.5 by 164 rating points16091773+164 rating
- LiveBench · CodingClaude Sonnet 5.5 by 12.47991.4+12.4
- SciCodeClaude Sonnet 5.5 by 9.451.661+9.4
- LiveBench · Agentic Codingtie56.856.3tie
AgentsClaude Sonnet 5.5
- Terminal-Bench 4.0Claude Sonnet 5.5 by 30.832.863.6+30.8
- GDPValClaude Sonnet 5.5 by 9.757.266.9+9.7
ReasoningClaude Sonnet 5.5
- ARC-AGI-2Claude Sonnet 5.5 by 18.165.883.9+18.1
- CritPtClaude Sonnet 5.5 by 1615.431.4+16
- Humanity's Last ExamClaude Sonnet 5.5 by 15.139.955+15.1
- LiveBench · ReasoningClaude Sonnet 5.5 by 1477.691.6+14
FactsClaude Sonnet 5.5
- AA-Omniscience · AccuracyClaude Sonnet 5.5 by 26.527.554+26.5
- AA-Omniscience · Non-hallucinationGLM-5.3-Flash by 19.472.453+19.4
- SimpleQA VerifiedClaude Sonnet 5.5 by 14.53246.5+14.5
Images and chartsGLM-5.3-Flash
- LMArena · VisionGLM-5.3-Flash by 11 rating points12951284+11 rating
MathClaude Sonnet 5.5
- FrontierMath Tier 4Claude Sonnet 5.5 by 63.417.180.5+63.4
- FrontierMath Tiers 1-3 (v2)Claude Sonnet 5.5 by 3355.888.8+33
- LiveBench · MathematicsClaude Sonnet 5.5 by 14.981.296.1+14.9
Following instructionsClaude Sonnet 5.5
- LiveBench · Instruction FollowingClaude Sonnet 5.5 by 452.856.8+4
Other results12 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.
- Terminal-Bench-Science 0.1Claude Sonnet 5.5 by 48.54.853.3+48.5
- HLE-DiamondClaude Sonnet 5.5 by 35.118.253.3+35.1
- CritPt v2 HardClaude Sonnet 5.5 by 34.524.559+34.5
- AA-OmniscienceClaude Sonnet 5.5 by 24.87.532.3+24.8
- GDPval-AA 2.1Claude Sonnet 5.5 by 195 rating points16491844+195 rating
- livebench_data_analysisGLM-5.3-Flash by 16.976.459.5+16.9
- AA IntelligenceClaude Sonnet 5.5 by 14.241.856+14.2
- GDP (Surge AI)Claude Sonnet 5.5 by 10.415.425.8+10.4
- DeepSWE 1.1Claude Sonnet 5.5 by 7.663.471+7.6
- ARC-AGI-1Claude Sonnet 5.5 by 5.59196.5+5.5
- OfficeQA ProClaude Sonnet 5.5 by 3.262.465.6+3.2
- livebench_languagetie77.378tie
Questions people ask
Which is better, GLM-5.3-Flash or Claude Sonnet 5.5?
Claude Sonnet 5.5 wins seven of the eight areas we test: coding, agents, reasoning, facts, math, long documents and following instructions. GLM-5.3-Flash wins images and charts, and costs 95% less.
Which is better for coding?
Claude Sonnet 5.5. It wins 3 of the 4 coding tests both models report; GLM-5.3-Flash wins none, and 1 is a tie.
Which is cheaper?
GLM-5.3-Flash costs $0.15 per million input tokens and $0.50 per million output tokens; Claude Sonnet 5.5 costs $2.00 and $10.00. That makes GLM-5.3-Flash about 95% cheaper for the same work.
How do you compare the two?
We use the 31 benchmark tests both models have published scores on. The verdict counts the 19 tests in the eight capability areas, and a gap under one point (ten on rating-style scales) counts as a tie. The other 12 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.