ClaudevsGPT

Claude Opus 5.5 vs o3

Side-by-side comparison of pricing, task quality, and projected cost at higher scale.

Pricing

Side-by-side pricing

Claude Opus 5.5

Flagship

o3

Mid-tier
Input $/MTok
$4.00
$2.00
Output $/MTok
$20.00
$8.00
Cache discount
95% off
75% off
Context
1,000K
200K

Quality

Task confidence comparison

Confidence score from zero to one hundred by task type, where higher is better.
Code Generation
0
vs
0
Code Review
0
vs
0
Summarization
0
vs
0
Q&A
0
vs
0
Extraction
0
vs
0
Reasoning
0
vs
0
Classification
0
vs
0
Creative Writing
0
vs
0
Claude Opus 5.5
o3

Guidance

When to use Claude Opus 5.5 vs o3

Choose Claude Opus 5.5 when...

  • -You need a larger context window (1,000K vs 200K)
  • Similar performance; consider provider preference or ecosystem fit.

Choose o3 when...

  • -Cost matters: 50% cheaper on input tokens

At scale

Cost at scale

Estimated cost assuming a seventy percent input and thirty percent output token split.
Claude Opus 5.5
o3
100K tokens
$0.88
$0.38Cheaper
1M tokens
$8.80
$3.80Cheaper
10M tokens
$88.00
$38.00Cheaper

FAQ

When should I use Claude Opus 5.5 instead of o3?

Claude Opus 5.5 and o3 perform similarly across all tracked tasks. Pick based on pricing and provider preference.

Is o3 cheaper than Claude Opus 5.5?

Yes. o3 input costs $2.00/MTok vs $4.00/MTok for Claude Opus 5.5, saving 50% on input.

What are the context window sizes for Claude Opus 5.5 and o3?

Claude Opus 5.5 has a 1,000K token context window. o3 has a 200K token context window.

Track your real costs

Comparisons show estimated costs at list price. The dashboard reveals your real spend and savings.