Claude Opus 4.5 vs GLM-5.1
Wins 2 of 7 areas
Facts · Long documents
Wins 2 of 7 areas
Agents · Following instructions
The two are evenly matched.Claude Opus 4.5 is better at facts and long documents; GLM-5.1 at agents and following instructions.
Scores updated · 36 tests both models report · How we compare
Where each one wins
Tests won in each of the seven 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.
- FactsGetting facts right instead of making them up21Claude Opus 4.52 of 3 tests
- Long documentsFinding answers in very long texts10Claude Opus 4.51 of 1 test
- AgentsCarrying out multi-step tasks on its own12GLM-5.12 of 3 tests
- Following instructionsDoing exactly what it is asked01GLM-5.11 of 1 test
- CodingWriting and fixing software33Even3 each · 1 tie
- ReasoningHard problems that need careful thinking00Even0 each · 3 ties
- MathCompetition and research-level math11Even1 each · 2 ties
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-5.1 costs 81% less for the same work.
The biggest differences
The three tests each model wins by the widest margin. Scores are out of 100.
Where Claude Opus 4.5 pulls ahead
- Answers hard knowledge questions correctlyAA-Omniscience · Accuracy+22.9points ahead
- Real work tasks from 44 professionsGDPVal+16.3points ahead
- Short factual questions, answered correctlySimpleQA Verified+11.7points ahead
Where GLM-5.1 pulls ahead
- Fixes real GitHub issues in many programming languagesSWE-bench Multilingual+66.3points ahead
- Finds hard-to-locate facts by browsing the webBrowseComp+42.3points ahead
- Avoids making up answers it doesn't knowAA-Omniscience · Non-hallucination+31.1points ahead
Every test, side by side
All 36 tests both models report. The winning score is in its model's colour; marks a score checked independently.
CodingEven
- SWE-bench MultilingualGLM-5.1 by 66.3773.3+66.3
- SWE-bench ProGLM-5.1 by 6.45258.4+6.4
- SciCodeClaude Opus 4.5 by 4.749.544.8+4.7
- SWE-bench VerifiedClaude Opus 4.5 by 4.780.976.2+4.7
- LMArena · WebDevGLM-5.1 by 39 rating points14691508+39 rating
- Terminal-Bench HardClaude Opus 4.5 by 3.84743.2+3.8
- LiveCodeBench v6tie84.885.7tie
AgentsGLM-5.1
- BrowseCompGLM-5.1 by 42.33779.3+42.3
- GDPValClaude Opus 4.5 by 16.347.331+16.3
- MCP AtlasGLM-5.1 by 9.562.371.8+9.5
ReasoningEven
- GPQA Diamondtie86.686.8tie
- CritPttie4.64.6tie
- Humanity's Last Examtie30.130.1tie
FactsClaude Opus 4.5
- AA-Omniscience · Non-hallucinationGLM-5.1 by 31.13970.1+31.1
- AA-Omniscience · AccuracyClaude Opus 4.5 by 22.946.623.7+22.9
- SimpleQA VerifiedClaude Opus 4.5 by 11.745.734+11.7
MathEven
- HMMT Feb. 2026Claude Opus 4.5 by 2.785.382.6+2.7
- FrontierMath Tiers 1-3 (v2)GLM-5.1 by 2.434.436.8+2.4
- AIME 2026tie95.195.3tie
- IMOAnswerBenchtie8483.8tie
Other results14 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 Agentic IndexClaude Opus 4.5 by 34.459.625.2+34.4
- CyberGymGLM-5.1 by 18.150.668.7+18.1
- AA-OmniscienceClaude Opus 4.5 by 13.1140.8+13.1
- Terminal-Bench 2.0GLM-5.1 by 9.759.369+9.7
- HLE (with tools)GLM-5.1 by 9.143.252.3+9.1
- frontiermath_tier_4_v1GLM-5.1 by 8.34.212.5+8.3
- τ²-Bench Telecom (AA run)GLM-5.1 by 8.289.597.7+8.2
- Artificial Analysis Coding IndexGLM-5.1 by 847.855.8+8
- LiveBenchClaude Opus 4.5 by 5.87670.2+5.8
- MMLU-ProClaude Opus 4.5 by 3.589.586+3.5
- AA IntelligenceClaude Opus 4.5 by 329.126.1+3
- ToolathlonClaude Opus 4.5 by 2.843.540.7+2.8
- HMMT Nov. 2025tie93.394tie
- NL2Repotie43.242.7tie
Questions people ask
Which is better, Claude Opus 4.5 or GLM-5.1?
Claude Opus 4.5 and GLM-5.1 each win two of the seven areas where both have results. Claude Opus 4.5 wins facts and long documents; GLM-5.1 wins agents and following instructions. GLM-5.1 costs 81% less. They are level on coding, reasoning and math.
Which is better for coding?
Neither. They win 3 coding tests each of the 7 both models report, and 1 is a tie.
Which is cheaper?
Claude Opus 4.5 costs $5.00 per million input tokens and $25.00 per million output tokens; GLM-5.1 costs $1.38 and $4.40. That makes GLM-5.1 about 81% cheaper for the same work.
How do you compare the two?
We use the 36 benchmark tests both models have published scores on. The verdict counts the 22 tests in the eight capability areas, and a gap under one point (ten on rating-style scales) counts as a tie. The other 14 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.