Claude Fable 5$22.000/MClaude Opus 4.8$11.000/MClaude Opus 4.7$11.000/MClaude Opus 4.6$11.000/MClaude Opus 4.5$33.000/MClaude Sonnet 3.7$6.600/MClaude Opus 3$33.000/MClaude 2.1$12.800/MClaude 2$12.800/MGPT-5.5$12.500/MGPT-5.2$5.425/MGPT-5.2-Codex$5.425/MGPT-5$3.875/MGPT-4.5$97.500/MGPT-4 Turbo Preview$16.000/MGPT-4$39.000/MGPT-4-32k$78.000/Mo3$19.000/Mo3-mini$2.090/Mo4-mini$2.090/Mo1$28.500/Mo1-mini$5.700/Mo1-preview$28.500/MGemini 3.5 Pro$5.000/MGemini 3.1 Pro$5.000/MGemini 3 Pro$5.000/MGemini 2.5 Pro$3.875/MGemini 1.5 Pro$2.375/MGemini 1.0 Ultra$12.000/MGemini 1.0 Pro$0.800/MClaude Fable 5$22.000/MClaude Opus 4.8$11.000/MClaude Opus 4.7$11.000/MClaude Opus 4.6$11.000/MClaude Opus 4.5$33.000/MClaude Sonnet 3.7$6.600/MClaude Opus 3$33.000/MClaude 2.1$12.800/MClaude 2$12.800/MGPT-5.5$12.500/MGPT-5.2$5.425/MGPT-5.2-Codex$5.425/MGPT-5$3.875/MGPT-4.5$97.500/MGPT-4 Turbo Preview$16.000/MGPT-4$39.000/MGPT-4-32k$78.000/Mo3$19.000/Mo3-mini$2.090/Mo4-mini$2.090/Mo1$28.500/Mo1-mini$5.700/Mo1-preview$28.500/MGemini 3.5 Pro$5.000/MGemini 3.1 Pro$5.000/MGemini 3 Pro$5.000/MGemini 2.5 Pro$3.875/MGemini 1.5 Pro$2.375/MGemini 1.0 Ultra$12.000/MGemini 1.0 Pro$0.800/M
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OpenAI
OpenAIReasoning

o1

Reasoning

The first o-series reasoning model — proved chain-of-thought scaling worked. Now superseded by o3 / o4-mini for new traffic.

o1 is a reasoning AI model from OpenAI. It costs $15.000 per million input tokens and $60.000 per million output tokens (blended $28.500/M), with a 200K-token context window.

Released Sep 2024Modalities textOfficial model page ↗Provider pricing ↗API docs ↗Compare with another model →Estimate monthly cost →
INPUT
$15.000/M
per million input tokens
OUTPUT
$60.000/M
per million output tokens
BLENDED 70/30
$28.500/M
default reference rate · how it's calculated →
CONTEXT
200K
200,000 tokens
What it's good at
  • Strong math & code
  • Multi-step reasoning
Typical use cases
  • Legacy o1 reasoning pipelines
  • Migration to o3
Benchmarks
vs. best public score
MMLU91%
Multitask academic knowledge across 57 subjects.
GPQA Diamond78%
Graduate-level science questions, "Google-proof".
MATH94%
High-school competition math problems.
HumanEval89%
Python function synthesis from docstrings.
LMArena Elo1355 Elo
Crowd-sourced head-to-head preference Elo rating.
Hand-curated from each provider's published reports and public leaderboards. Methodology varies across sources — treat as directional rather than authoritative.
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GPT-5.2-Codex
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in $1.750/Mout $14.000/M
GPT-5
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in $1.250/Mout $10.000/M
GPT-4.1
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in $2.000/Mout $8.000/M
GPT-4.1 mini
Efficient · 1M ctx
in $0.400/Mout $1.600/M
Frequently asked questions

How much does o1 cost?

o1 costs $15.000 per million input tokens and $60.000 per million output tokens, for a blended reference rate of $28.500 per million tokens.

What is o1's context window?

o1 supports up to 200K tokens of context (200,000 tokens).

What is o1 best for?

o1 is well suited to Strong math & code, Multi-step reasoning and Legacy o1 reasoning pipelines.

Who makes o1?

o1 is developed and served by OpenAI. It was released in Sep 2024.