Head-to-head · frontier vs frontier

Claude 3.7 Sonnet Max vs o3: which model should you choose?

We compared Claude 3.7 Sonnet Max and o3 on price, context window and 12 benchmarks. o3 has the stronger average benchmark score; o3 is cheaper on a blended 3:1 basis.

Anthropic

Claude 3.7 Sonnet Max

Claude 3.7 Sonnet Max is a frontier model from Anthropic. It offers a 128,000-token context window, costs $16.88 per million input tokens and $83.20 per million output tokens, and averages 83.7 across the index's benchmark suite.

Input: $16.88 / 1M
Output: $83.20 / 1M
Context: 128,000
Avg score: 83.7
Open weights: No

Full Claude 3.7 Sonnet Max page

OpenAI

o3

o3 is a frontier model from OpenAI. It offers a 400,000-token context window, costs $16.80 per million input tokens and $81.80 per million output tokens, and averages 84.5 across the index's benchmark suite.

Input: $16.80 / 1M
Output: $81.80 / 1M
Context: 400,000
Avg score: 84.5
Open weights: No

Full o3 page

Specification comparison

Spec	Claude 3.7 Sonnet Max	o3	Edge
Input price / 1M	$16.88	$16.80	B
Output price / 1M	$83.20	$81.80	B
Context window	128,000	400,000	B
Max output	32,768	4,096	A
Average score	83.7	84.5	B
Arena Elo	1461.6	1449.0	A
Open weights	No	No	Tie

Benchmark comparison

Claude 3.7 Sonnet Max wins 5, o3 wins 7, and 0 benchmarks are tied. The table shows the modelled score for each model and the gap.

Benchmark	Claude 3.7 Sonnet Max	o3	Gap	Winner
MMLU-Pro	86.0	86.9	0.9	o3
GPQA Diamond	76.8	78.3	1.5	o3
SWE-bench Verified	76.1	72.9	3.2	Claude 3.7 Sonnet Max
HumanEval	90.9	89.8	1.1	Claude 3.7 Sonnet Max
MATH-500	87.2	87.9	0.7	o3
AIME 2025	80.7	84.4	3.7	o3
LiveCodeBench	78.1	80.7	2.6	o3
IFEval	90.0	88.7	1.3	Claude 3.7 Sonnet Max
TruthfulQA	84.7	84.6	0.1	Claude 3.7 Sonnet Max
HellaSwag	91.2	92.7	1.5	o3
MMMU	78.8	82.3	3.5	o3
Arena Elo	1461.6	1449.0	12.6	Claude 3.7 Sonnet Max

Price analysis

On a blended 3:1 input-to-output basis, Claude 3.7 Sonnet Max costs about $33.46 per million tokens and o3 costs about $33.05. o3 is roughly 1% cheaper than Claude 3.7 Sonnet Max. At high volume, that gap compounds quickly, so price should carry real weight unless the quality difference is decisive.

o3 has the larger context window at 400,000 tokens, compared with 128,000 for Claude 3.7 Sonnet Max. That matters for long documents, large codebases and multi-step agent traces.

Verdict

Across 12 shared benchmarks, Claude 3.7 Sonnet Max wins 5, o3 wins 7, and 0 are tied. On the index average, o3 leads Claude 3.7 Sonnet Max by 0.8 points (84.5 versus 83.7).

The price picture favours o3. The context picture favours o3. Those two dimensions often matter more than a few benchmark points once a model is good enough for the task.

If you need a single default, start with o3 for quality-sensitive work, and check whether its price holds at your expected volume before committing.

Choose Claude 3.7 Sonnet Max if

You need the larger 32,768-token output limit.

Choose o3 if

You want the higher average benchmark score in this index.
Unit cost matters and you want the cheaper blended price.
You need the larger 400,000-token context window.

FAQ

Is Claude 3.7 Sonnet Max better than o3?

On the index average, o3 leads Claude 3.7 Sonnet Max by 0.8 points (84.5 versus 83.7). The better choice depends on price, context and your task. Claude 3.7 Sonnet Max wins 5 benchmarks, o3 wins 7.

Which is cheaper, Claude 3.7 Sonnet Max or o3?

o3 is cheaper on a blended 3:1 basis at about $33.05 per million tokens, versus $33.46 for Claude 3.7 Sonnet Max.

Which has the larger context window?

o3 has the larger context window at 400,000 tokens. Claude 3.7 Sonnet Max has 128,000 tokens.

Are these models open weights?

Claude 3.7 Sonnet Max is proprietary; o3 is proprietary.

Which should I choose for production?