Gemini 2.5 Pro vs o3
Complete pricing and performance comparison between Google's Gemini 2.5 Pro and OpenAI's o3.
Quick Verdict
Cheaper
Gemini 2.5 Pro (input) / o3 (output)
Input: 1.6x diff, Output: 1.3x diff
Larger Context
Gemini 2.5 Pro
1.0M vs 200K
Higher Quality
o3
Score: 38 vs 35
Faster
Gemini 2.5 Pro
128 vs 79 tok/s
Pricing Comparison
| Spec | Gemini 2.5 Pro | o3 | Difference |
|---|---|---|---|
| Provider | OpenAI | ||
| Input / 1M tokens | $1.25 | $2 | Gemini 2.5 Pro is 38% more expensive |
| Output / 1M tokens | $10 | $8 | o3 is 20% more expensive |
| Context Window | 1.0M | 200K | 5x difference |
| Max Output | 66K | 100K | |
| Tokenizer | cl100k_base | o200k_base |
Performance Benchmarks
| Metric | Gemini 2.5 Pro | o3 | Winner |
|---|---|---|---|
| Quality Index | 35 | 38 | o3 |
| Output Speed | 128 tok/s | 79 tok/s | Gemini 2.5 Pro |
| Time to First Token | 22.13s | 10.83s | o3 |
| Value (Quality/$) | 27.7 | 19.2 | Higher = better value |
Benchmark data from Artificial Analysis. Quality Index is a composite score across reasoning, coding, and knowledge tasks.
Cost at Scale
Estimated cost at different usage levels (3:1 input-to-output token ratio, typical for chat).
| Usage | Gemini 2.5 Pro | o3 | Savings |
|---|---|---|---|
Single request 1K in / 300 out | $0.0042 | $0.0044 | Same |
10 requests 10K in / 3K out | $0.042 | $0.044 | Gemini 2.5 Pro saves $0.0015 |
100 requests 100K in / 30K out | $0.425 | $0.440 | Gemini 2.5 Pro saves $0.015 |
1,000 requests 1M in / 300K out | $4.25 | $4.40 | Gemini 2.5 Pro saves $0.150 |
10,000 requests 10M in / 3M out | $42.50 | $44.00 | Gemini 2.5 Pro saves $1.50 |
1M requests/mo 1B in / 300M out | $4250.00 | $4400.00 | Gemini 2.5 Pro saves $150.00 |
Pros & Cons
Gemini 2.5 Pro Strengths
- +Cheaper input tokens
- +Larger context window (1.0M vs 200K)
- +Faster output (128 vs 79 tok/s)
o3 Strengths
- +Cheaper output tokens
- +Higher max output tokens
- +Higher quality score (38 vs 35)
- +Lower latency (faster first token)
When to Use Each Model
Choose Gemini 2.5 Pro for
- →Long documents, large codebases, or multi-turn conversations
- →Real-time applications, chat, or autocomplete
Choose o3 for
- →Generating long-form content or detailed code
- →Tasks requiring maximum accuracy and reasoning
Frequently Asked Questions
Which is cheaper, Gemini 2.5 Pro or o3?
For input tokens, Gemini 2.5 Pro is 1.6x cheaper at $1.25/1M tokens. For output tokens, o3 is 1.3x cheaper at $8/1M tokens. At typical usage (1M input + 300K output), Gemini 2.5 Pro costs $4.25 vs o3 at $4.40.
What's the context window difference?
Gemini 2.5 Pro supports 1.0M context (1,048,576 tokens), while o3 supports 200K (200,000 tokens). Gemini 2.5 Pro can handle 5x more context in a single request.
Which model has better benchmarks?
Quality Index: Gemini 2.5 Pro scores 35 vs o3 at 38. Speed: Gemini 2.5 Pro generates 128 tok/s vs o3 at 79 tok/s. Time to first token: Gemini 2.5 Pro at 22.13s vs o3 at 10.83s.
When should I choose Gemini 2.5 Pro over o3?
Choose Gemini 2.5 Pro when you need: Cheaper input tokens, Larger context window (1.0M vs 200K), Faster output (128 vs 79 tok/s). Choose o3 when you need: Cheaper output tokens, Higher max output tokens, Higher quality score (38 vs 35), Lower latency (faster first token).
How much would 10,000 API requests cost?
At 1K input + 300 output tokens per request (typical chat): Gemini 2.5 Pro = $42.50, o3 = $44.00. At 10K input + 1K output per request (longer conversations): Gemini 2.5 Pro = $225.00, o3 = $280.00.