Compare/Claude Opus 4.5 (Reasoning) vs GPT-5.5 (high)

Claude Opus 4.5 (Reasoning)vsGPT-5.5 (high)

Side-by-side comparison of pricing, 12 benchmarks, and generation speed.

Anthropic

Claude Opus 4.5 (Reasoning)

Input
$6.25/M
Output
$25/M
Speed
66 tok/s
TTFT
11.93s
OpenAI

GPT-5.5 (high)

Input
$5/M
Output
$30/M
Speed
61 tok/s
TTFT
19.21s

Winner by Category

Cheaper
Claude Opus 4.5 (Reasoning)
Faster (tok/s)
Claude Opus 4.5 (Reasoning)
Lower Latency
Claude Opus 4.5 (Reasoning)
Benchmarks (4-7)
GPT-5.5 (high)

Pricing Comparison

MetricClaude Opus 4.5 (Reasoning)GPT-5.5 (high)
Input ($/M tokens)$6.25$5
Output ($/M tokens)$25$30
Cost for 1M input + 100K output tokens:
Claude Opus 4.5 (Reasoning)$8.75
GPT-5.5 (high)$8.00

Speed Comparison

Output Speed (tokens/s) — higher is better
Claude Opus 4.5 (Reasoning)
66 tok/s
GPT-5.5 (high)
61 tok/s
Time to First Token (seconds) — lower is better
Claude Opus 4.5 (Reasoning)
11.93s
GPT-5.5 (high)
19.21s

Benchmark Comparison

Data from Artificial Analysis API — 12 benchmarks

Intelligence Index
49.758.9
Coding Index
47.858.5
Math Index
91.3
GPQA Diamond
86.6%93.2%
MMLU-Pro
89.5%
LiveCodeBench
87.1%
AIME 2025
91.3%
MATH-500
Humanity's Last Exam
28.4%43.0%
SciCode
49.5%55.9%
IFBench
58.0%71.6%
TerminalBench
47.0%59.8%
Claude Opus 4.5 (Reasoning)4 wins
7 winsGPT-5.5 (high)

Frequently Asked Questions

Which is cheaper, Claude Opus 4.5 (Reasoning) or GPT-5.5 (high)?

Claude Opus 4.5 (Reasoning) is cheaper overall. Its blended price (3:1 input/output ratio) is $10.94/M tokens vs $11.25/M for GPT-5.5 (high).

Which model performs better on benchmarks?

GPT-5.5 (high) wins 7 out of 12 benchmarks compared to 4 for Claude Opus 4.5 (Reasoning). See the detailed benchmark chart above for per-category results.

Which is faster for real-time applications?

Claude Opus 4.5 (Reasoning) generates tokens faster at 66 tok/s vs 61 tok/s. Claude Opus 4.5 (Reasoning) also has lower time-to-first-token (11.93s vs 19.21s).

When should I use Claude Opus 4.5 (Reasoning) vs GPT-5.5 (high)?

Choose based on your priorities: Claude Opus 4.5 (Reasoning) for lower cost, GPT-5.5 (high) for stronger benchmark performance, and Claude Opus 4.5 (Reasoning) for faster generation. For latency-sensitive apps, check the TTFT comparison above.