Knowledge
Directional only- GPT-5.5 Pro
- 59.6
- Estimated · #38/186
- o1
- 45.3
- Supported · #114/186
- Basis
- BenchAlign lane · 2 vs 2 public rows
- Reading
- Directional only
GPT-5.5 Pro vs o1
Decision reading
GPT-5.5 Pro has the higher public score estimate, 62.2 versus 46.48, but the 90% score intervals overlap. Treat that as a lead, not a settled winner.
1 results are shared. Category rows resting on Estimated evidence or different benchmark sets are marked directional and do not name a winner.
Updated September 21, 2026. Rank says GPT-5.5 Pro is ahead. Price, access, and your workload can each overturn that. Public scores include evidence status and uncertainty.
Both of these models will change. Get the price, version and retirement notices for the pair, each with its source. Follow model changes
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.
Long documents
Prompts that approach the documented context limit
GPT-5.5 Pro
GPT-5.5 Pro has the larger documented context window.
Confidence: documented
Chat turn cost
1K fresh input + 500 output tokens
o1
o1 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
o1
o1 has the lower estimated token cost for this stated workload. Costs use the listed standard API rates.
Confidence: listed-rates
Coding work
Code generation, repair, and software-engineering tasks
Not enough matched evidence
GPT-5.5 Pro is not ranked on the public lane for coding, so no winner is named for coding.
Confidence: limited
Agentic work
Tool use, computer use, and multi-step task completion
Not enough matched evidence
O1 is not ranked on the public lane for agentic, so no winner is named for agentic.
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. o1 does not fit this workload in one request. GPT-5.5 Pro has no published cached-input rate, so cached tokens use its listed input rate. o1 has no published cached-input rate, so cached tokens use its listed input rate.
Confidence: rate-fallback
Which one for a specific job
Choose a job from the LLM Selector's task catalog to see the category row it rests on, under the same basis rules as the table below. A directional row stays directional; choosing a job never creates a winner.
The same task catalog as the LLM Selector. Each job names the evidence surface it rests on; nothing here adds a new score.
—GPT-5.5 Pro44.8o1
Not comparable · BenchAlign
The coding row is not comparable on the public lane: at least one model is not measured or not ranked there.
Coding scores combine specific tasks and setups. Match the editor, harness, and effort to your workflow.
What is actually comparable
Shared results can support a head-to-head reading. Results present for only one model describe coverage, not superiority.
5 GPT-5.5 Pro only
1 Shared
3 o1 only
- Shared results
- 1
- GPT-5.5 Pro only
- 5
- o1 only
- 3
- Like-for-like categories
- 0 / 8
1 category rests 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.
Agentic
Not comparable- GPT-5.5 Pro
- 59.2
- Estimated · #27/154
- o1
- Not ranked
- Basis
- BenchAlign lane · 1 vs 0 public rows
- Reading
- Not comparable
Coding
Not comparable- GPT-5.5 Pro
- Not ranked
- o1
- 44.8
- Estimated · #98/156
- Basis
- BenchAlign lane · 0 vs 0 public rows
- Reading
- Not comparable
Reasoning
Not comparable- GPT-5.5 Pro
- Not ranked
- o1
- 65.7
- Unranked · 2 rankable rows
- Basis
- Provisional lane · 0 vs 0 weighted rows
- Reading
- Not comparable
Multimodal
Not comparable- GPT-5.5 Pro
- Not ranked
- o1
- Not ranked
- Basis
- Provisional lane · 0 vs 0 weighted rows
- Reading
- Not comparable
Multilingual
Not comparable- GPT-5.5 Pro
- Not ranked
- o1
- Not ranked
- Basis
- Provisional lane · 0 vs 0 weighted rows
- Reading
- Not comparable
Instruction following
Not comparable- GPT-5.5 Pro
- Not ranked
- o1
- 84.5
- #40/124
- Basis
- Provisional lane · 0 vs 0 weighted rows
- Reading
- Not comparable
Math
Not comparable- GPT-5.5 Pro
- 70.1
- Unranked · 3 rankable rows
- o1
- 32.5
- Unranked · 1 rankable row
- Basis
- Provisional lane · 2 vs 1 weighted rows
- Reading
- Not comparable
| Category | GPT-5.5 Pro | o1 | Basis | Reading |
|---|---|---|---|---|
| Knowledge | 59.6Estimated · #38/186 | 45.3Supported · #114/186 | Directional onlyBenchAlign lane · 2 vs 2 public rows | Directional only |
| Agentic | 59.2Estimated · #27/154 | Not ranked | Not comparableBenchAlign lane · 1 vs 0 public rows | Not comparable |
| Coding | Not ranked | 44.8Estimated · #98/156 | Not comparableBenchAlign lane · 0 vs 0 public rows | Not comparable |
| Reasoning | Not ranked | 65.7Unranked · 2 rankable rows | Not comparableProvisional lane · 0 vs 0 weighted rows | Not comparable |
| Multimodal | Not ranked | Not ranked | Not comparableProvisional lane · 0 vs 0 weighted rows | Not comparable |
| Multilingual | Not ranked | Not ranked | Not comparableProvisional lane · 0 vs 0 weighted rows | Not comparable |
| Instruction following | Not ranked | 84.5#40/124 | Not comparableProvisional lane · 0 vs 0 weighted rows | Not comparable |
| Math | 70.1Unranked · 3 rankable rows | 32.5Unranked · 1 rankable row | Not comparableProvisional lane · 2 vs 1 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 (Tiers 1-3)
Math
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
- GPT-5.5 Pro
- $0.12
- Fits in one request
- o1
- $0.045
- Fits in one request
o1 has the lower modeled cost
Costs use the listed standard API rates.
Repository review
50K fresh input + 3K output tokens
- GPT-5.5 Pro
- $2.04
- Fits in one request
- o1
- $0.93
- Fits in one request
o1 has the lower modeled cost
Costs use the listed standard API rates.
Cache-heavy agent loop
200K cached + 20K fresh input + 10K output tokens
- GPT-5.5 Pro
- $8.40
- Fits in one request
- Cached input priced at the published list-input rate
- o1
- $3.90
- Does not fit in one request
- Cached input priced at the published list-input rate
o1 does not fit this workload in one request. GPT-5.5 Pro has no published cached-input rate, so cached tokens use its listed input rate. o1 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.
SpecificationGPT-5.5 Proo1
Context window
Maximum documented context; output-token limits may be lower.
GPT-5.5 Pro
o1
200K
API model ID
GPT-5.5 Pro
gpt-5.5-pro
OpenAI GPT-5.5 Pro model documentationo1
Not sourced
Cached-input rate
A missing cached-input rate falls back to the listed input rate only in the stated workload estimate.
GPT-5.5 Pro
Not published
OpenAI pricingo1
Not published
Documented inputs
GPT-5.5 Pro
text, image
OpenAI model catalogo1
Not sourced
Documented outputs
GPT-5.5 Pro
o1
Not sourced
Provider availability
GPT-5.5 Pro
Generally Available · OpenAI Responses API
OpenAI model catalogo1
Not sourced
Reasoning profile
GPT-5.5 Pro
Reasoning
o1
Reasoning
Weight access
GPT-5.5 Pro
Proprietary
o1
Proprietary
License
GPT-5.5 Pro
Proprietary
o1
Proprietary
Release date
GPT-5.5 Pro
2026-04-23
o1
2024-12-01
If you already use one of these models
- Deployment change
- Both entries list OpenAI as the provider. Confirm endpoint, model ID, limits, and feature support before switching.
- Quality signal
- GPT-5.5 Pro has the higher public score estimate, 62.2 versus 46.48, but the 90% score intervals overlap.
- Workload cost
- Repository review: $2.04 vs $0.93. Cache-heavy agent loop: $8.40 vs $3.90.
- Context tradeoff
- GPT-5.5 Pro has the larger documented window (1.05M).
Run the same representative tasks against both endpoints before changing production traffic.
Benchmark evidence
The full public result ledger is available for audit without forcing a wide desktop table onto a phone.
Browse raw public benchmark evidence9 rows
Agentic
BrowseComp
GPT-5.5 Pro90.1%Sourceo1—Not directly comparable
Knowledge
Instruction following
IFEval
GPT-5.5 Pro—o192.2%SourceNot directly comparable
Math
FrontierMath (legacy)
GPT-5.5 Pro52.4%Sourceo1—Not directly comparable
FrontierMath v2 (Tiers 1-3)
Shared sourceGPT-5.5 Pro51.000%o19.310%GPT-5.5 Pro leads this result
FrontierMath v2 (Tier 4)
GPT-5.5 Pro39.600%Sourceo1—Not directly comparable
Questions
Which is better, GPT-5.5 Pro or o1?
GPT-5.5 Pro has the higher public score estimate, 62.2 versus 46.48, but the 90% score intervals overlap. The higher estimate is not a decisive winner because the uncertainty ranges overlap.
Which is better for coding, GPT-5.5 Pro or o1?
GPT-5.5 Pro is not ranked on the public lane for coding, so no winner is named for coding.
Which is better for agentic tasks, GPT-5.5 Pro or o1?
O1 is not ranked on the public lane for agentic tasks, so no winner is named for agentic tasks.
Which costs less, GPT-5.5 Pro or o1?
For the stated presets, chat costs $0.12 on GPT-5.5 Pro and $0.045 on o1; repository review costs $2.04 and $0.93; the cache-heavy agent loop costs $8.40 and $3.90. o1 does not fit this workload in one request. GPT-5.5 Pro has no published cached-input rate, so cached tokens use its listed input rate. o1 has no published cached-input rate, so cached tokens use its listed input rate.
Which has the larger context window, GPT-5.5 Pro or o1?
GPT-5.5 Pro has the larger documented context window: 1.05M, compared with 200K.
Related comparisons
Last updated September 21, 2026
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