GPT-4o vs GPT-5.1

At a Glance

Compare
GPT-4oOpenAI
GPT-5.1OpenAI
Intelligence, Cost, and Efficiency
IntelligenceHigher is better · MM Intelligence v2.5UnrankedNot in the 46-model eligible cohort#37 of 4625.7 score · 2/3 sources · provisional · missing LiveBench · full-core range 17.1–50.5
Pricing and Limits
Input priceFrom · USD / 1M tokens$1.25Openrouter · Sep 22, 2026$1.25Openai · Sep 3, 2026
Output priceFrom · USD / 1M tokens$5.00Openrouter · Sep 22, 2026$10.00Openai · Sep 3, 2026
Context windowMaximum documented tokens128K400K
Model facts checkedAug 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

All benchmark results →
BenchmarkGPT-4oGPT-5.1
LMArena Text Arenatext-2026-09-13-d25aabda0010 · arena_rating · leader1,282.4590% of row best · rating · gpt-4o-2024-08-06; 95% CI [1278.25455133, 1286.63762056]; votes 45499; rank 2541,422.57100% of row best · rating · gpt-5.1; 95% CI [1418.95842118, 1426.18777801]; votes 42982; rank 100
LMArena Vision Arenavision-2026-09-13-d25aabda0010 · arena_rating · leader1,064.5686% of row best · rating · gpt-4o-2024-08-06; 95% CI [1052.10383916, 1077.00692124]; votes 3376; rank 1231,235.08100% of row best · rating · gpt-5.1; 95% CI [1227.35514387, 1242.80648733]; votes 10205; rank 65
ToneBench2026-09-11-10-task-4ef099199c9c · overall_score · unverified58.6677% of row best · points · GPT-4o · 1,174 output tokens / case75.98100% of row best · points · GPT-5.1 · 3,970 output tokens / case
Overall ResultCounted from the protocol-matched rows above0 benchmark winsNo overall winner2 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

FieldGPT-4oGPT-5.1
DeveloperOpenAIOpenAI
FamilyGpt 4oGpt 5 1
ModelGPT-4oGPT-5.1
VersionGPT-4oGPT-5.1
Lifecycleactiveactive
ReleasedUnknown2025-11-13
Knowledge cutoff2023-10-012024-09-30
Input modalitiesText, ImageText, Image
Output modalitiesTextText
Context window128K400K
Total parametersUnknownUnknown
Active parametersUnknownUnknown
LicenseUnknownUnknown
Open weightsNoNo
API availableYesYes
Self-hostableNoNo
Provider accessOpenai (Standard), Openrouter (Standard)Openai (Standard), Openrouter (Standard)
Capabilitieschat, generation, toolschat, generation, reasoning, structured_outputs, tools

GPT-4o Capabilities

chatgenerationtools
Serving providers2
Canonical IDopenai/gpt-4o

GPT-5.1 Capabilities

chatgenerationreasoningstructured outputstools
Serving providers2
Canonical IDopenai/gpt-5.1

Primary Evidence

Sources and Freshness

Questions

GPT-4o vs GPT-5.1 FAQs

Is GPT-4o or GPT-5.1 better for coding?+

This comparison does not currently contain a protocol-matched coding benchmark for both GPT-4o and GPT-5.1, so Model Markets cannot name a coding leader from pricing, context size, or capability labels alone.

Which is cheaper, GPT-4o or GPT-5.1?+

GPT-4o is $1.25 and GPT-5.1 is $1.25 per million tokens, so they are tied on this metric. GPT-4o is $5.00 and GPT-5.1 is $10.00 per million tokens, so GPT-4o is cheaper on this metric.

Which has a larger context window, GPT-4o or GPT-5.1?+

GPT-5.1 has the larger sourced context window. GPT-4o supports 128K and GPT-5.1 supports 400K.

Which performs better in benchmarks, GPT-4o or GPT-5.1?+

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-5.1 be self-hosted?+

Both models have the same recorded self-hosting status: unsupported. GPT-4o is not marked open weight; GPT-5.1 is not marked open weight.

Can GPT-4o and GPT-5.1 understand images?+

GPT-4o is documented with image input; GPT-5.1 is documented with image input. This reflects supported input modalities, not vision quality.

Which can generate longer answers, GPT-4o or GPT-5.1?+

GPT-5.1 has the larger sourced maximum output: GPT-4o supports 16K and GPT-5.1 supports 128K output tokens.

Do GPT-4o and GPT-5.1 support reasoning and tool use?+

GPT-4o: tool calling and image input. GPT-5.1: reasoning, tool calling, and image input. Feature support does not establish relative quality.

Which is available from more inference providers, GPT-4o or GPT-5.1?+

GPT-4o has 2 sourced provider routes; GPT-5.1 has 2, a tie.

Which offers better value, GPT-4o or GPT-5.1?+

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.

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