Level : Intermediate

Compare AI models side by side

Pick 2 to 4 AI models and see their prices, context window, features and benchmark scores at a glance. This guide explains every row of the comparison tool and helps you choose the right model for your use case.

Laptop screen showing several aligned columns, like a side-by-side AI model comparison

Comparing 2 models: GPT-5.5 Pro, Claude Sonnet 5.5.

Comparison of the selected models, criterion by criterion
CriterionGPT-5.5 ProOpenAIClaude Sonnet 5.5Anthropic
API price
Input priceUSD per million tokens$30.00median of 20 providers$2.00 (best value)
Output priceUSD per million tokens$180.00median of 20 providers$10.00 (best value)
Window, output and date
Context windowtokens1,050,000 (best value)1,000,000
Maximum outputtokens100,000128,000 (best value)
Release dateApr 23, 2026Sep 28, 2026 (best value)
Open weights✗ No✗ No
Capabilities
Tools (function calling)✓ Yes✓ Yes
Reasoning✓ Yes✓ Yes
Vision (images)✓ Yes✓ Yes
Audio✗ No✗ No
Benchmark scores
Composite indexout of 100, at least 3 benchmarks96.9 (best value)95.9
GPQA DiamondPhD-level science questions93.9%95.6% (best value)
OTIS Mock AIMEcompetition mathematics problems100%100%
FrontierMathvery hard research-level mathematics87.7%88.8% (best value)
FrontierCodeadvanced programming tasks—52.1%
APEX-Agentsprofessional tasks carried out by an agent—75.5%
Humanity's Last Exammultidisciplinary expert questions—46.1%

Verdict by criterion

  • Cheapest input: Claude Sonnet 5.5
  • Cheapest output: Claude Sonnet 5.5
  • Largest context window: GPT-5.5 Pro
  • Longest possible output: Claude Sonnet 5.5
  • Most recent: Claude Sonnet 5.5
  • Best composite index: GPT-5.5 Pro
  • Best score on GPQA Diamond: Claude Sonnet 5.5
  • Best score on FrontierMath: Claude Sonnet 5.5

Public API prices in USD excluding tax, collected on October 22, 2026. “Median of N providers”: the developer's own price is not in the source, so we use the median price of the providers that serve the model. Index and scores come from the same data as the AI ranking; “—” means the model was not evaluated on that test. The verdict compares figures row by row: it is not a recommendation.

Model comparisons

Frontier models

Open-weight models

Budget models

Mid-range models

Developers' flagship models

How to use the comparison tool

Type a few letters of a model’s name in the search box and the list filters instantly. Add 2 to 4 models and their specs line up row by row for easy reading. For each criterion, an automatic verdict flags the model that comes out ahead (cheapest, largest context window, best score, and so on). The share link lets you send your comparison to a colleague or come back to it later.

What each row means

Token. The basic unit a model reads and writes: a fragment of text, often part of a word. Everything is counted in tokens, from pricing to text length. To see how many tokens your text represents, try the token estimator.

Input and output price. Both are shown per million tokens. Input is what you send to the model (your question, a document, the conversation history); output is what it sends back. Output is usually the more expensive of the two.

Context window. The model’s “working memory”: the maximum amount of text it can take into account at once, prompt and documents included. A large window lets you analyze a long report in one go. The context window tool helps you picture what that means.

Max output. The maximum length of a single answer. It is often much shorter than the context window: a model may read a very long document yet only write a reply of limited length.

Features. Tools: the model can call external functions (search, calculations, software), which is essential for building an agent. Reasoning: it can “think” step by step before answering, useful for complex problems. Vision: it understands images. Audio: it handles sound or voice.

Open weights. Weights are the parameters a model learns during training. When they are published, you can download the model and run it on your own servers, which is a game changer for privacy. Otherwise, the model is only available through its maker’s service.

Release date. Handy for spotting recent models, but an older model is often still a great choice if it is cheap and good enough for the job.

Benchmark scores. Results on standardized tests, drawn from the same data as our AI ranking. An empty cell means the model was not evaluated on that test, not that it failed.

How to choose for your use case

  • Writing and everyday questions: a budget model is usually enough. Focus on the output price.
  • Long document analysis: favor a large context window and check the input price, since that is what adds up when you send lots of text.
  • Agents and automations: make sure the tools feature is there, then estimate the bill with the AI agent cost calculator, because an agent makes many calls in a row.
  • Sensitive data: an open-weight model, hosted by you or a provider you trust, limits where your data travels. See our pick of open source AI models.
  • Hard problems (code, math, logic): the reasoning feature and benchmark scores move to the top of the list.

Common pitfalls

  • Only looking at the input price. A model that is cheap on input can get expensive if your answers are long.
  • Forgetting reasoning tokens. Models that “think” often generate intermediate tokens, usually billed as output. Your real bill can end up higher than your estimate.
  • Assuming a huge context is always fully used. Quality can drop when the window is filled to the brim; send only what is relevant.
  • Treating the automatic verdict as advice. It compares figures row by row without knowing your use case. Weighing the criteria is up to you.
  • Mixing up models and assistants. If you are looking for a personal subscription, the AI assistants comparison is a better fit.

Frequently asked questions

What is a token, in plain terms?

A token is a small chunk of text, often part of a word, that the model reads or writes. AI models are billed by the number of tokens they process. The exact token count for a given text depends on the model and the language.

Why do output tokens cost more than input tokens?

Generating text takes more computing than reading it, because the model produces its answer token by token. That is why most labs charge more for output than for input. If your use involves long answers, check the output price first.

Are these the prices of ChatGPT Plus or other subscriptions?

No. The comparison tool shows API prices, meaning pay-as-you-go access to the model for developers and automated tools. Consumer assistant subscriptions work differently and are covered in our AI assistants comparison.

Can I share my comparison?

Yes. The share link stores the selected models in the page address. Anyone who opens it sees the same comparison, with data current at the time they view the page.

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