Best models

Best AI models for reasoning

Every model in the live reference catalogue with a reasoning mode, ranked by the intelligence index (Artificial Analysis, 0-100) with vendor list prices per million tokens. 12 qualify today.

Strongest

Claude Opus 5.5

intelligence index 58 · $8.00 blended

Best value

Muse Spark 1.3

48 points for $2.00

Cheapest

Muse Spark 1.3

$2.00 blended · index 48

Ranked by the intelligence index

Strongest first; price breaks ties. Value is index points per blended dollar. Click a model for its full specification, or compare two side by side.

#	Model	Intelligence index	Input / 1M	Output / 1M	Context	Value	Compare
1	Claude Opus 5.5Anthropic	58	$4.00	$20.0	1M	7
2	Claude Sonnet 5.5Anthropic	56	$2.00	$10.0	1M	14	vs Claude Opus 5.5
3	Claude Fable 5.1Anthropic	53	$10.0	$50.0	1M	3	vs Claude Opus 5.5
4	GPT-6 AstraOpenAI	53	$10.0	$50.0	1.1M	3	vs Claude Opus 5.5
5	Gemini 4 ArgonGoogle	53	$2.00	$10.0	1.0M	13	vs Claude Opus 5.5
6	GPT-6.1 SolOpenAI	52	$2.00	$10.0	1.1M	13	vs Claude Opus 5.5
7	Claude Opus 5Anthropic	51	$5.00	$25.0	1M	5	vs Claude Opus 5.5
8	Claude Fable 5Anthropic	50	$10.0	$50.0	1M	2	vs Claude Opus 5.5
9	Muse Spark 1.3Meta	48	$1.25	$4.25	1.0M	24	vs Claude Opus 5.5
10	GPT-6 SolOpenAI	48	$2.00	$10.0	1.1M	12	vs Claude Opus 5.5
11	GPT-5.6 SolOpenAI	47	$4.00	$20.0	1.1M	6	vs Claude Opus 5.5
12	Grok 4.7xAI	46	$2.00	$6.00	500K	15	vs Claude Opus 5.5

What to weigh for reasoning

Reasoning models think before they answer: they generate a chain of intermediate tokens the user never sees and pay for. That makes them markedly better at maths, planning and anything with several dependent steps, and markedly more expensive per request - the hidden tokens are billed as output. Only models that publish a reasoning mode qualify for this list.

The intelligence index is the broadest composite (reasoning, knowledge, instruction following), which is why it is the one to rank reasoning models by. Read the price column with the thinking in mind: a reasoning model at the same list price as a plain one costs several times more per request because it writes several times more tokens.

The router's job here is restraint. Most requests do not need a reasoning model, and sending them one is the most common way AI spend doubles without anyone deciding it should. The rule below reserves reasoning models for requests whose complexity signal is high and whose wording asks for analysis; everything else goes to the cheapest model that meets the quality floor, and a bad outcome on that model escalates the next similar request.

The rule, in OpenSmartRoute

Declare the models as targets and let the rule send the hard requests to the strongest one and the rest to the best value; the trace names the rule that fired.

yaml

# rules.yaml - reasoning: the strongest qualifying model for the hard requests, the best value for the rest
rules:
  - name: reasoning-hard
    when: { actions: [reasoning], min_complexity: 0.6 }
    prefer: [claude-opus-5.5]
    weight: 0.8
  - name: reasoning-default
    when: { max_complexity: 0.45 }
    prefer: [muse-spark-1.3]
    weight: 0.6

Try a request Price a workload

Frequently asked

What is a reasoning model?: A model that generates intermediate thinking tokens before its answer. They score higher on multi-step problems and cost more per request because the thinking is billed as output.
Should every request go to a reasoning model?: No. For short, factual or formatting requests a plain model answers as well at a fraction of the cost. The router routes by the request's complexity so reasoning models get only the requests that need them.
How does the router know a request is hard?: From signals it extracts before routing - length, nesting, the verbs and domains in the text, constraints - combined into a complexity score the rules can test, as the rule on this page does.

Best models for other tasks

For the business

What it means for which models you pay for.

Catalogue of every vendor
The right model, not the famous one
Price, context, abilities and benchmark indexes side by side, with the model that fits each task named.
The rankings
89% less
Lower cost per request
On the 150-prompt benchmark the router spent 89% less than sending every prompt to the reference model, and the judged quality went up, not down.
Read the benchmark
Per million tokens, every model
Prices you can compare
The catalogue prints input and output prices and what three typical monthly workloads cost on each.
The model catalogue

Which LLM is the cheapest for our workload?: The best-for pages rank the live catalogue per task by the index that measures it, and the router picks the cheapest model that meets your quality rule for each request.
How much can we save on our LLM bill?: On the public benchmark the router saved 89% against sending everything to the reference model. Import last month's provider bill on the bill page and the estimate is computed on your own traffic before you change a line of code.
How often do model prices change?: The catalogue is refreshed from the vendors' price lists; each model page shows the date of its data.

Let the router pick the reasoning model per request.

The ranking above is where to start; the router finishes the job - the strongest qualifying model for the hard requests, the best value for the rest, and every decision explained.

Create a free account Price a workload

Free plan, no card. Fifteen thousand decisions a month with the full trace.

Model

Intelligence index

Input / 1M

Output / 1M

Context

Value

Compare

Claude Opus 5.5Anthropic

$4.00

$20.0

Claude Sonnet 5.5Anthropic

$2.00

$10.0

vs Claude Opus 5.5

Claude Fable 5.1Anthropic

$10.0

$50.0

vs Claude Opus 5.5

GPT-6 AstraOpenAI

$10.0

$50.0

1.1M

vs Claude Opus 5.5

Gemini 4 ArgonGoogle

$2.00

$10.0

1.0M

vs Claude Opus 5.5

GPT-6.1 SolOpenAI

$2.00

$10.0

1.1M

vs Claude Opus 5.5

Claude Opus 5Anthropic

$5.00

$25.0

vs Claude Opus 5.5

Claude Fable 5Anthropic

$10.0

$50.0

vs Claude Opus 5.5

Muse Spark 1.3Meta

$1.25

$4.25

1.0M

vs Claude Opus 5.5

GPT-6 SolOpenAI

$2.00

$10.0

1.1M

vs Claude Opus 5.5

GPT-5.6 SolOpenAI

$4.00

$20.0

1.1M

vs Claude Opus 5.5

Grok 4.7xAI

$2.00

$6.00

500K

vs Claude Opus 5.5

What to weigh for reasoning

The rule, in OpenSmartRoute

Declare the models as targets and let the rule send the hard requests to the strongest one and the rest to the best value; the trace names the rule that fired.

yaml

# rules.yaml - reasoning: the strongest qualifying model for the hard requests, the best value for the rest
rules:
  - name: reasoning-hard
    when: { actions: [reasoning], min_complexity: 0.6 }
    prefer: [claude-opus-5.5]
    weight: 0.8
  - name: reasoning-default
    when: { max_complexity: 0.45 }
    prefer: [muse-spark-1.3]
    weight: 0.6

Frequently asked

What is a reasoning model?

A model that generates intermediate thinking tokens before its answer. They score higher on multi-step problems and cost more per request because the thinking is billed as output.

Should every request go to a reasoning model?

No. For short, factual or formatting requests a plain model answers as well at a fraction of the cost. The router routes by the request's complexity so reasoning models get only the requests that need them.

How does the router know a request is hard?

From signals it extracts before routing - length, nesting, the verbs and domains in the text, constraints - combined into a complexity score the rules can test, as the rule on this page does.

Best AI models for reasoning

Ranked by the intelligence index

What to weigh for reasoning

The rule, in OpenSmartRoute

Frequently asked

Related

Best models for other tasks

What it means for which models you pay for.

The right model, not the famous one

Lower cost per request

Prices you can compare

Let the router pick the reasoning model per request.

Best AI models for reasoning

Ranked by the intelligence index

What to weigh for reasoning

The rule, in OpenSmartRoute

Frequently asked

Related

Best models for other tasks

What it means for which models you pay for.

The right model, not the famous one

Lower cost per request

Prices you can compare

Let the router pick the reasoning model per request.