GPT-4o vs GPT-5.5
At a Glance
| Compare |  GPT-4oOpenAI | GPT-5.5OpenAI |
|---|---|---|
| Intelligence, Cost, and Efficiency | ||
| IntelligenceHigher is better · MM Intelligence v2.5 | UnrankedNot in the 46-model eligible cohort | #7 of 4683.9 score · 3/3 sources · complete |
| CostLower is better · Published-token output estimate | UnrankedNot in the 44-model eligible cohort | #38 of 44$0.341 per LiveBench case |
| EfficiencyHigher is better · MM Efficiency v1.5 | UnrankedNot in the 38-model eligible cohort | #18 of 3853.4 score · 3/3 sources · complete |
| Pricing and Limits | ||
| Input priceFrom · USD / 1M tokens | $1.25Openrouter ↗ · Sep 22, 2026 | $5.00Openai ↗ · Sep 3, 2026 |
| Output priceFrom · USD / 1M tokens | $5.00Openrouter ↗ · Sep 22, 2026 | $30.00Openai ↗ · Sep 3, 2026 |
| Context windowMaximum documented tokens | 128K | 1,050K |
| Model facts checked | Aug 29, 2026View model evidence → | Sep 3, 2026View model evidence → |
Token prices are the lowest available sourced USD rates; input and output may use different providers. Cost ranking estimates output spend on LiveBench, not a full request bill. Ranking methodology →
Available Benchmarks
| Benchmark | GPT-4o | GPT-5.5 |
|---|---|---|
| LMArena Text Arenatext-2026-09-13-d25aabda0010 · arena_rating · leader | 1,282.4588% of row best · rating · gpt-4o-2024-08-06; 95% CI [1278.25455133, 1286.63762056]; votes 45499; rank 254 | 1,465.59100% of row best · rating · gpt-5.5; 95% CI [1461.82849712, 1469.35015015]; votes 66317; rank 31 |
| LMArena Vision Arenavision-2026-09-13-d25aabda0010 · arena_rating · leader | 1,064.5682% of row best · rating · gpt-4o-2024-08-06; 95% CI [1052.10383916, 1077.00692124]; votes 3376; rank 123 | 1,294.19100% of row best · rating · gpt-5.5-high; 95% CI [1287.85384790, 1300.52893287]; votes 21960; rank 20 |
| ToneBench2026-09-11-10-task-4ef099199c9c · overall_score · unverified | 58.6671% of row best · points · GPT-4o · 1,174 output tokens / case | 82.60100% of row best · points · GPT-5.5 (xhigh) · 4,050 output tokens / case |
| Overall ResultCounted from the protocol-matched rows above | 0 benchmark winsNo overall winner | 2 benchmark winsNo overall winner |
Third-party benchmark Only like-for-like primary-publisher results are shown; raw scores, relative scores, configuration, and token spend remain visible.
Side-by-Side Facts
| Field | GPT-4o | GPT-5.5 |
|---|---|---|
| Developer | OpenAI | OpenAI |
| Family | Gpt 4o | Gpt 5 5 |
| Model | GPT-4o | GPT-5.5 |
| Version | GPT-4o | GPT-5.5 |
| Lifecycle | active | active |
| Released | Unknown | 2026-04-23 |
| Knowledge cutoff | 2023-10-01 | 2025-12-01 |
| Input modalities | Text, Image | Text, Image |
| Output modalities | Text | Text |
| Context window | 128K | 1,050K |
| Total parameters | Unknown | Unknown |
| Active parameters | Unknown | Unknown |
| License | Unknown | Unknown |
| Open weights | No | No |
| API available | Yes | Yes |
| Self-hostable | No | No |
| Provider access | Openai (Standard), Openrouter (Standard) | Openai (Standard), Openrouter (Standard) |
| Capabilities | chat, generation, tools | chat, generation, reasoning, structured_outputs, tools |
GPT-4o Capabilities
GPT-5.5 Capabilities
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Primary Evidence
Sources and Freshness
Questions
GPT-4o vs GPT-5.5 FAQs
Is GPT-4o or GPT-5.5 better for coding?+
This comparison does not currently contain a protocol-matched coding benchmark for both GPT-4o and GPT-5.5, so Model Markets cannot name a coding leader from pricing, context size, or capability labels alone.
Which is cheaper, GPT-4o or GPT-5.5?+
GPT-4o is $1.25 and GPT-5.5 is $5.00 per million tokens, so GPT-4o is cheaper on this metric. GPT-4o is $5.00 and GPT-5.5 is $30.00 per million tokens, so GPT-4o is cheaper on this metric.
Which has a larger context window, GPT-4o or GPT-5.5?+
GPT-5.5 has the larger sourced context window. GPT-4o supports 128K and GPT-5.5 supports 1,050K.
Which performs better in benchmarks, GPT-4o or GPT-5.5?+
There is no overall benchmark winner: An overall winner requires at least two decisive benchmarks from at least two original publishers.
Can GPT-4o or GPT-5.5 be self-hosted?+
Both models have the same recorded self-hosting status: unsupported. GPT-4o is not marked open weight; GPT-5.5 is not marked open weight.
Can GPT-4o and GPT-5.5 understand images?+
GPT-4o is documented with image input; GPT-5.5 is documented with image input. This reflects supported input modalities, not vision quality.
Which can generate longer answers, GPT-4o or GPT-5.5?+
GPT-5.5 has the larger sourced maximum output: GPT-4o supports 16K and GPT-5.5 supports 128K output tokens.
Do GPT-4o and GPT-5.5 support reasoning and tool use?+
GPT-4o: tool calling and image input. GPT-5.5: reasoning, tool calling, and image input. Feature support does not establish relative quality.
Which is available from more inference providers, GPT-4o or GPT-5.5?+
GPT-4o has 2 sourced provider routes; GPT-5.5 has 2, a tie.
Which offers better value, GPT-4o or GPT-5.5?+
There is no universal value winner. Compare the input and output prices above with the matched benchmark result for your workload: cheaper tokens can be offset by different quality, token usage, latency, or provider availability.