GLM-5.3 vs GPT-5.5
Wins 2 of 7 areas
Coding · Agents
Wins 5 of 7 areas
Reasoning · Facts · Math · Long documents · Following instructions
GPT-5.5 is the stronger all-rounder.GLM-5.3 is cheaper and better at agents.
Both rank among the ten best models we track in agents.
Scores updated · 40 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.
- ReasoningHard problems that need careful thinking05GPT-5.55 of 5 tests
- MathCompetition and research-level math03GPT-5.53 of 3 tests
- FactsGetting facts right instead of making them up12GPT-5.52 of 3 tests
- Long documentsFinding answers in very long texts01GPT-5.51 of 1 test
- Following instructionsDoing exactly what it is asked01GPT-5.51 of 1 test
- AgentsCarrying out multi-step tasks on its own30GLM-5.33 of 4 tests · 1 tie
- CodingWriting and fixing software31GLM-5.33 of 5 tests · 1 tie
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 costs 83% less for the same work.
The biggest differences
The three tests each model wins by the widest margin. Scores are out of 100.
Where GPT-5.5 pulls ahead
- Extremely hard research-level math problemsFrontierMath Tier 4+43.2points ahead
- Answers hard knowledge questions correctlyAA-Omniscience · Accuracy+24.1points ahead
- Short factual questions, answered correctlySimpleQA Verified+22points ahead
Where GLM-5.3 pulls ahead
- Avoids making up answers it doesn't knowAA-Omniscience · Non-hallucination+59.4points ahead
- Complex command-line tasks across many fieldsTerminal-Bench 4.0+27.3points ahead
- Real work tasks from 44 professionsGDPVal+14.9points ahead
Every test, side by side
All 40 tests both models report. The winning score is in its model's colour; marks a score checked independently.
CodingGLM-5.3
- LMArena · WebDevGLM-5.3 by 111 rating points16231512+111 rating
- LiveBench · Agentic CodingGLM-5.3 by 6.960.954+6.9
- LiveBench · CodingGPT-5.5 by 3.27982.2+3.2
- SciCodeGLM-5.3 by 3.25955.8+3.2
- Terminal-Bench 2.1tie83.984.3tie
AgentsGLM-5.3
- Terminal-Bench 4.0GLM-5.3 by 27.341.914.6+27.3
- GDPValGLM-5.3 by 14.957.642.7+14.9
- τ-Bench V3 · BankingGLM-5.3 by 11.350.339+11.3
- AA IT-Bench SREtie46.145.8tie
ReasoningGPT-5.5
- CritPtGPT-5.5 by 819.127.1+8
- LiveBench · ReasoningGPT-5.5 by 3.985.889.7+3.9
- Humanity's Last ExamGPT-5.5 by 3.542.345.8+3.5
- SimpleBenchGPT-5.5 by 2.866.269+2.8
- GPQA DiamondGPT-5.5 by 1.891.793.5+1.8
FactsGPT-5.5
- AA-Omniscience · Non-hallucinationGLM-5.3 by 59.470.411+59.4
- AA-Omniscience · AccuracyGPT-5.5 by 24.133.958+24.1
- SimpleQA VerifiedGPT-5.5 by 224163+22
MathGPT-5.5
- FrontierMath Tier 4GPT-5.5 by 43.229.372.5+43.2
- FrontierMath Tiers 1-3 (v2)GPT-5.5 by 16.568.885.3+16.5
- LiveBench · MathematicsGPT-5.5 by 887.995.9+8
Following instructionsGPT-5.5
- LiveBench · Instruction FollowingGPT-5.5 by 1.469.370.7+1.4
Other results18 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.
- Program BenchGPT-5.5 by 51.81970.8+51.8
- SWE-MarathonGLM-5.3 by 30.542.512+30.5
- GDPval-AA v2GLM-5.3 by 260 rating points17691509+260 rating
- ToolathlonGLM-5.3 by 17.47355.6+17.4
- AA Agentic IndexGLM-5.3 by 16.153.437.3+16.1
- livebench_data_analysisGPT-5.5 by 11.470.281.6+11.4
- PostTrainBenchGLM-5.3 by 11.439.828.4+11.4
- HLE (with tools)GLM-5.3 by 10.362.552.2+10.3
- livebench_languageGPT-5.5 by 7.579.987.4+7.5
- NL2RepoGLM-5.3 by 7.35850.7+7.3
- AA IntelligenceGLM-5.3 by 6.444.838.4+6.4
- AA-OmniscienceGPT-5.5 by 6.214.320.5+6.2
- DeepSWEGPT-5.5 by 3.166.970+3.1
- CyberGymGLM-5.3 by 2.784.581.8+2.7
- Agents' Last ExamGLM-5.3 by 1.928.526.6+1.9
- Toolathlon Verifiedtie7373.5tie
- Artificial Analysis Coding Indextie74.874.9tie
- DeepSWE 1.1tie66.967tie
Questions people ask
Which is better, GLM-5.3 or GPT-5.5?
GPT-5.5 wins five of the seven areas where both have results: reasoning, facts, math, long documents and following instructions. GLM-5.3 wins coding and agents, and costs 83% less.
Which is better for coding?
GLM-5.3. It wins 3 of the 5 coding tests both models report; GPT-5.5 wins 1, and 1 is a tie.
Which is cheaper?
GLM-5.3 costs $1.40 per million input tokens and $4.40 per million output tokens; GPT-5.5 costs $5.00 and $30.00. That makes GLM-5.3 about 83% cheaper for the same work.
How do you compare the two?
We use the 40 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 18 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.