Tool review · Generative AI

o1 review

o1 is a large language model from OpenAI. Its strengths are notably more careful on multi-step problems; fewer confident errors on logic-heavy tasks. The main caution: slower and more expensive than general-purpose models. It has been superseded by a newer release, so compare it with current options before adopting it.

What it is

Legacy model, superseded by the GPT-6 family. o1 is an earlier OpenAI reasoning model designed to think through a problem before answering. It was built for math, science and coding tasks where a slower, more careful answer beats a fast one.

Key features

  • Extended reasoning before responding
  • Strong on math, logic and code problems
  • Structured outputs and function calling
  • Available through the OpenAI API

Pros

  • Notably more careful on multi-step problems
  • Fewer confident errors on logic-heavy tasks
  • Clear fit for technical analysis

Cons

  • Slower and more expensive than general-purpose models
  • Superseded by newer OpenAI reasoning models
  • Overkill for simple drafting

Pricing

o1 is priced by usage rather than by seat: API: $15 in / $60 out per M tokens. That means cost scales with how much text you send and receive, so estimate your monthly volume before committing.

How to get started

Start with one real task you already do each week, give the model the full context, and compare the result with your usual output before changing your workflow. Keep sensitive client or patient data out of consumer chat apps unless your organization has approved the plan.

Alternatives to consider

  • ChatGPT (OpenAI, $20/mo): OpenAI's flagship conversational AI.
  • Claude (Anthropic, $20/mo): Anthropic's assistant, known for long-context reasoning, careful writing, and safety-aware outputs.
  • Claude Fable 5 (Anthropic, API: $10 in / $50 out per M tokens): Claude Fable 5 is a premium-tier Claude model priced above Opus, aimed at the hardest professional and technical work.
  • Claude Fable 5.1 (Anthropic, API: $10 in / $50 out per M tokens): Claude Fable 5.1 is Anthropic's premium generally available model, priced above Opus and built for the hardest reasoning, coding and analysis tasks.
  • Claude Haiku 4.5 (Anthropic, API: $1 in / $5 out per M tokens): Claude Haiku 4.5 is Anthropic's fast, low-cost model at $1 and $5 per million tokens.

Frequently asked questions

What is o1?

Legacy model, superseded by the GPT-6 family. o1 is an earlier OpenAI reasoning model designed to think through a problem before answering.

How much does o1 cost?

o1 is priced by usage rather than by seat: API: $15 in / $60 out per M tokens. That means cost scales with how much text you send and receive, so estimate your monthly volume before committing.

Is there a free version of o1?

o1 does not currently list a permanent free tier. Look for a trial or a low-cost plan to test it on real work first.

What are the alternatives to o1?

Comparable generative ai options we review include ChatGPT, Claude, Claude Fable 5 and Claude Fable 5.1. Read each review to compare pricing, strengths and limits.

Independent review by the AI by Career editorial team. Last reviewed September 2026. No paid placement or affiliate influence; see our editorial policy.