o3 vs Gemini 2.5 Pro

API pricing, benchmark indices and specs — updated 19 October 2026.

openai · A · API-only
Input / 1M
$2.00
Output / 1M
$8.00
AA index
20.2
proprietary · 200K context
google · B · API-only
Input / 1M
$1.25
Output / 1M
$10.00
AA index
16.1
proprietary · 1M context

Specification comparison

Differences are highlighted; identical values are muted.

Specification o3 Gemini 2.5 Pro
Deployment API-only (closed weights) API-only (closed weights)
Parameters n/a — API-only n/a — API-only
Architecture n/a — API-only n/a — API-only
Context length 200,000 1,048,576
Licence Proprietary Proprietary
Commercial use Per API terms Per API terms
Languages n/a — API-only n/a — API-only
Downloads 30d n/a — API-only n/a — API-only
Downloads all time n/a — API-only n/a — API-only
Quantizations on the Hub n/a — API-only n/a — API-only
Gated n/a — API-only n/a — API-only
First seen on the Hub n/a — API-only n/a — API-only
API input price / 1M tokens $2.00 $1.25
API output price / 1M tokens $8.00 $10.00
Est. cost per 1M input + 1M output tokens $10.00 $11.25
Cached input / 1M tokens $0.50 $0.13
AA Intelligence Index 20.2 16.1
AA Coding Index — 33.3
AA Agentic Index — 1.6
Max output tokens 100,000 65,536
API providers 1 1
Tool calling Yes Yes
Reasoning mode Yes Yes

API cost

Estimated cost of 1M input + 1M output tokens via OpenRouter

o3 $10.00
Gemini 2.5 Pro $11.25

o3 is 1.1× cheaper at list price.

Adjacent comparisons