Coding
Like-for-like- GLM-5.1
- 56.8
- Supported · #39/183
- GPT-5.5
- 67.7
- Supported · #8/183
- Basis
- BenchAlign lane · 7 vs 9 public rows
- Reading
- GPT-5.5 leads · intervals overlap
GLM-5.1 vs GPT-5.5
Updated September 4, 2026. Public scores include evidence status and uncertainty. They are not guarantees for a specific workload.
Decision reading
GPT-5.5 has the higher public score estimate, 73.27 versus 64.41, but the 90% score intervals overlap. Treat that as a lead, not a settled winner.
17 results are shared. Category rows resting on Estimated evidence or different benchmark sets are marked directional and do not name a winner.
Share or export
Which one for your work
Recommendations appear only when a shared evidence basis or an explicit operating constraint supports the call. Secondary and unsupported use cases stay disclosed below the initial list.
Coding work
Code generation, repair, and software-engineering tasks
GPT-5.5
GPT-5.5 leads on the public coding lane, 67.7 to 56.8, with Supported evidence for both models, although the 90% intervals overlap.
Confidence: limited
Long documents
Prompts that approach the documented context limit
GPT-5.5
GPT-5.5 has the larger documented context window.
Confidence: documented
Chat turn cost
1K fresh input + 500 output tokens
GLM-5.1
GLM-5.1 has the lower estimated token cost for this stated workload. Costs use the listed standard API rates.
Confidence: listed-rates
Show secondary and unsupported calls
Repository review cost
50K fresh input + 3K output tokens
GLM-5.1
GLM-5.1 has the lower estimated token cost for this stated workload. Costs use the listed standard API rates.
Confidence: listed-rates
Agentic work
Tool use, computer use, and multi-step task completion
Not enough matched evidence
GLM-5.1 is scored on Estimated evidence for agentic, so the reading is directional rather than like-for-like.
Confidence: limited
Cache-heavy agent loop cost
200K cached + 20K fresh input + 10K output tokens
Not enough matched evidence
The page does not recommend a cost winner because at least one model cannot fit the stated workload in one request. GLM-5.1 does not fit this workload in one request. GLM-5.1 has no published cached-input rate, so cached tokens use its listed input rate.
Confidence: rate-fallback
What is actually comparable
Shared results can support a head-to-head reading. Results present for only one model describe coverage, not superiority.
9 GLM-5.1 only
17 Shared
21 GPT-5.5 only
- Shared results
- 17
- GLM-5.1 only
- 9
- GPT-5.5 only
- 21
- Like-for-like categories
- 2 / 8
2 categories rest on Estimated evidence or different evidence sets. Those rows remain visible for coverage context but do not name a winner.
Category results, on a stated basis
Each row shows the public-lane category score for both models: the BenchAlign lane for agentic, coding, and knowledge, and the weighted public rows elsewhere, with the same rank each model page reports. A row is like-for-like only when both scores rest on Supported evidence or the same weighted set. Directional and not-comparable rows remain visible, but they never receive a winner.
Knowledge
Like-for-like- GLM-5.1
- 55.4
- Supported · #59/181
- GPT-5.5
- 73.3
- Supported · #7/181
- Basis
- BenchAlign lane · 4 vs 6 public rows
- Reading
- GPT-5.5 leads · intervals overlap
Agentic
Directional only- GLM-5.1
- 50.1
- Estimated · #63/151
- GPT-5.5
- 63.9
- Supported · #15/151
- Basis
- BenchAlign lane · 9 vs 13 public rows
- Reading
- Directional only
Instruction following
Directional only- GLM-5.1
- 93.5
- #5/120
- GPT-5.5
- 92.9
- #7/120
- Basis
- Provisional lane · 0 vs 0 weighted rows
- Reading
- Directional only
Reasoning
Not comparable- GLM-5.1
- 69.9
- Unranked · 2 rankable rows
- GPT-5.5
- 63.5
- #15/22
- Basis
- Provisional lane · 0 vs 2 weighted rows
- Reading
- Not comparable
Math
Not comparable- GLM-5.1
- 64.1
- #3/7
- GPT-5.5
- 69.6
- Unranked · 3 rankable rows
- Basis
- Provisional lane · 4 vs 2 weighted rows
- Reading
- Not comparable
Multilingual
Not comparable- GLM-5.1
- Not ranked
- GPT-5.5
- Not ranked
- Basis
- Provisional lane · 0 vs 0 weighted rows
- Reading
- Not comparable
Multimodal
Not comparable- GLM-5.1
- Not ranked
- GPT-5.5
- 71.3
- #19/48
- Basis
- Provisional lane · 0 vs 2 weighted rows
- Reading
- Not comparable
| Category | GLM-5.1 | GPT-5.5 | Basis | Reading |
|---|---|---|---|---|
| Coding | 56.8Supported · #39/183 | 67.7Supported · #8/183 | Like-for-likeBenchAlign lane · 7 vs 9 public rows | GPT-5.5 leads · intervals overlap |
| Knowledge | 55.4Supported · #59/181 | 73.3Supported · #7/181 | Like-for-likeBenchAlign lane · 4 vs 6 public rows | GPT-5.5 leads · intervals overlap |
| Agentic | 50.1Estimated · #63/151 | 63.9Supported · #15/151 | Directional onlyBenchAlign lane · 9 vs 13 public rows | Directional only |
| Instruction following | 93.5#5/120 | 92.9#7/120 | Directional onlyProvisional lane · 0 vs 0 weighted rows | Directional only |
| Reasoning | 69.9Unranked · 2 rankable rows | 63.5#15/22 | Not comparableProvisional lane · 0 vs 2 weighted rows | Not comparable |
| Math | 64.1#3/7 | 69.6Unranked · 3 rankable rows | Not comparableProvisional lane · 4 vs 2 weighted rows | Not comparable |
| Multilingual | Not ranked | Not ranked | Not comparableProvisional lane · 0 vs 0 weighted rows | Not comparable |
| Multimodal | Not ranked | 71.3#19/48 | Not comparableProvisional lane · 0 vs 2 weighted rows | Not comparable |
Ranks count the models scored in each category’s lane, so the agentic, coding, and knowledge denominators (BenchAlign) differ from the provisional-lane categories. Unranked scores sit on the lane’s scale but never name a winner. Like-for-like rows within 0.5 points read as a practical tie.
Shape of the matched evidence
Only shared public evidence is shown. Sparse evidence stays a ruled list rather than being closed into a radar shape.
Too few matched category axes support a radar. The ruled list below shows only shared benchmark results; positions use each benchmark’s normalized display scale when available.
FrontierMath v2 (Tier 4)
Math
Terminal-Bench 2.0
Agentic
FrontierMath v2 (Tiers 1-3)
Math
BrowseComp
Agentic
LiveCodeBench (Vals)
Coding
What each workload costs
Three fixed token mixes turn per-token rates into comparable decisions. Each scenario states context fit and whether cached input had to fall back to the published list-input rate.
Chat turn
1K fresh input + 500 output tokens
- GLM-5.1
- $0.0036
- Fits in one request
- GPT-5.5
- $0.02
- Fits in one request
GLM-5.1 has the lower modeled cost
Costs use the listed standard API rates.
Repository review
50K fresh input + 3K output tokens
- GLM-5.1
- $0.0832
- Fits in one request
- GPT-5.5
- $0.34
- Fits in one request
GLM-5.1 has the lower modeled cost
Costs use the listed standard API rates.
Cache-heavy agent loop
200K cached + 20K fresh input + 10K output tokens
- GLM-5.1
- $0.352
- Does not fit in one request
- Cached input priced at the published list-input rate
- GPT-5.5
- $0.5
- Fits in one request
GLM-5.1 does not fit this workload in one request. GLM-5.1 has no published cached-input rate, so cached tokens use its listed input rate.
Specification differences
Sourced differences are shown directly. Missing facts stay explicit instead of being inferred from a model name or family.
SpecificationGLM-5.1GPT-5.5
Context window
Maximum documented context; output-token limits may be lower.
GLM-5.1
203K
GPT-5.5
API model ID
GLM-5.1
Not sourced
GPT-5.5
gpt-5.5
OpenAI pricingCached-input rate
A missing cached-input rate falls back to the listed input rate only in the stated workload estimate.
GLM-5.1
Not published
GPT-5.5
$0.5 per 1M cached input tokens
OpenAI pricingDocumented inputs
GLM-5.1
Not sourced
GPT-5.5
Not sourced
Documented outputs
GLM-5.1
Not sourced
GPT-5.5
Not sourced
Provider availability
GLM-5.1
Not sourced
GPT-5.5
Not sourced
Reasoning profile
GLM-5.1
Reasoning
GPT-5.5
Reasoning
Weight access
GLM-5.1
Open Weight
GPT-5.5
Proprietary
License
GLM-5.1
Open Weight
GPT-5.5
Proprietary
Release date
GLM-5.1
2026-04-07
GPT-5.5
2026-04-23
If you already use one of these models
- Deployment change
- The models list different providers, so authentication, endpoint behavior, limits, and feature support may change.
- Quality signal
- GPT-5.5 has the higher public score estimate, 73.27 versus 64.41, but the 90% score intervals overlap.
- Workload cost
- Repository review: $0.0832 vs $0.34. Cache-heavy agent loop: $0.352 vs $0.5.
- Context tradeoff
- GPT-5.5 has the larger documented window (1M).
Run the same representative tasks against both endpoints before changing production traffic.
Self-host vs API cost
Estimates at 50,000 req/day · 1000 tokens/req average.
GLM-5.1
API / mo$4,350
Self-host / mo$18,221
Break-even264M/day
GPT-5.5
API / mo$26,250
Self-host / moNot listed
Break-even—
Proprietary model — self-hosting not applicable.
Benchmark evidence
The full public result ledger is available for audit without forcing a wide desktop table onto a phone.
Browse raw public benchmark evidence47 rows
Agentic
Terminal-Bench 2.0
GLM-5.163.5%SourceGPT-5.582%SourceGPT-5.5 leads this result
BrowseComp
GLM-5.168%SourceGPT-5.584.4%SourceGPT-5.5 leads this result
τ³-bench results
GLM-5.170.6%SourceGPT-5.5—Not directly comparable
MCP Atlas
GLM-5.171.8%SourceGPT-5.575.3%SourceGPT-5.5 leads this result
CyberGym
GLM-5.168.7%SourceGPT-5.581.8%SourceGPT-5.5 leads this result
Claw-Eval
GLM-5.162.3%SourceGPT-5.5—Not directly comparable
Gert Labs
Shared sourceGLM-5.160.11%GPT-5.572.93%GPT-5.5 leads this result
ResearchClawBench
Shared sourceGLM-5.118.2%GPT-5.517.0%GLM-5.1 leads this result
Terminal-Bench 2.1 (Vals)
GLM-5.156.9%SourceGPT-5.576.4%SourceGPT-5.5 leads this result
OSWorld-Verified
GLM-5.1—GPT-5.578.7%SourceNot directly comparable
Toolathlon
GLM-5.1—GPT-5.555.6%SourceNot directly comparable
τ²-bench results
GLM-5.1—GPT-5.598%SourceNot directly comparable
OSWorld 2.0
GLM-5.1—GPT-5.513.0%SourceNot directly comparable
JobBench
GLM-5.1—GPT-5.542.7%SourceNot directly comparable
ExploitGym
GLM-5.1—GPT-5.513.4%SourceNot directly comparable
Coding
SWE-bench Pro
GLM-5.158.4%SourceGPT-5.558.6%SourceGPT-5.5 leads this result
NL2Repo
GLM-5.142.7%SourceGPT-5.5—Not directly comparable
SWE-Rebench
GLM-5.162.7%SourceGPT-5.5—Not directly comparable
Vibe Code Bench
Shared sourceGLM-5.131.46%GPT-5.569.85%GPT-5.5 leads this result
OpenHarmony Bench
GLM-5.152.3%SourceGPT-5.5—Not directly comparable
LiveCodeBench (Vals)
GLM-5.181.4%SourceGPT-5.585.3%SourceGPT-5.5 leads this result
SWE-bench (Vals)
GLM-5.176.4%SourceGPT-5.582.6%SourceGPT-5.5 leads this result
Terminal-Bench 2.0
GLM-5.1—GPT-5.582.0%SourceNot directly comparable
React Native Evals
GLM-5.1—GPT-5.584.7%SourceNot directly comparable
cursorBench31
GLM-5.1—GPT-5.559.2%SourceNot directly comparable
cursorBench32
GLM-5.1—GPT-5.558.4%SourceNot directly comparable
FrontierCode 1.1 Main
GLM-5.1—GPT-5.543.0%SourceNot directly comparable
Reasoning
Knowledge
GPQA-D
GLM-5.186.2%SourceGPT-5.593.6%SourceGPT-5.5 leads this result
HLE
GLM-5.152.3%SourceGPT-5.552.2%SourceGLM-5.1 leads this result
GPQA Diamond (Vals)
GLM-5.184.5%SourceGPT-5.593.2%SourceGPT-5.5 leads this result
MMLU-Pro (Vals)
GLM-5.186.9%SourceGPT-5.588.1%SourceGPT-5.5 leads this result
GPQA
GLM-5.1—GPT-5.593.6%SourceNot directly comparable
HLE w/o tools
GLM-5.1—GPT-5.541.4%SourceNot directly comparable
Math
AIME26
GLM-5.195.3%SourceGPT-5.5—Not directly comparable
HMMT Nov 2025
GLM-5.194.0%SourceGPT-5.5—Not directly comparable
HMMT Feb 2026
GLM-5.182.6%SourceGPT-5.5—Not directly comparable
MMAnswerBench
GLM-5.183.8%SourceGPT-5.5—Not directly comparable
FrontierMath v2 (Tiers 1-3)
Shared sourceGLM-5.133.448%GPT-5.551.700%GPT-5.5 leads this result
FrontierMath v2 (Tier 4)
Shared sourceGLM-5.112.500%GPT-5.535.400%GPT-5.5 leads this result
FrontierMath (legacy)
GLM-5.1—GPT-5.551.7%SourceNot directly comparable
Multimodal
Frequently asked questions
Which is better, GLM-5.1 or GPT-5.5?
GPT-5.5 has the higher public score estimate, 73.27 versus 64.41, but the 90% score intervals overlap. The higher estimate is not a decisive winner because the uncertainty ranges overlap.
Which is better for coding, GLM-5.1 or GPT-5.5?
GPT-5.5 leads the public coding lane, 67.7 to 56.8, with Supported evidence for both models, although the 90% intervals overlap.
Which is better for agentic tasks, GLM-5.1 or GPT-5.5?
GPT-5.5 scores higher for agentic tasks on the public lane, 63.9 to 50.1. GLM-5.1 is scored on Estimated evidence for agentic tasks, so the reading is directional rather than like-for-like. BenchLM does not name a winner for agentic tasks from a directional reading; read the shared benchmark rows directly and test the models on the same task set.
Which costs less, GLM-5.1 or GPT-5.5?
For the stated presets, chat costs $0.0036 on GLM-5.1 and $0.02 on GPT-5.5; repository review costs $0.0832 and $0.34; the cache-heavy agent loop costs $0.352 and $0.5. GLM-5.1 does not fit this workload in one request. GLM-5.1 has no published cached-input rate, so cached tokens use its listed input rate.
Which has the larger context window, GLM-5.1 or GPT-5.5?
GPT-5.5 has the larger documented context window: 1M, compared with 203K.
Related comparisons
Last updated September 4, 2026
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