Gemini 2.5 Pro vs GPT-5 Nano: Detailed Comparison
Choosing between Gemini 2.5 Pro (Google) and
GPT-5 Nano (OpenAI) comes down to three things:
per-token pricing, context window, and which capability matters most for your workload.
Gemini 2.5 Pro costs $1.25/M input vs
$0.05/M for GPT-5 Nano;
context windows are 2.0M vs
400K tokens. Detailed breakdown below.
Side-by-side specs
| Spec | Gemini 2.5 Pro | GPT-5 Nano |
|---|
| Provider | Google | OpenAI |
|---|
| Released | 2025-03-25 | 2025-08-07 |
|---|
| Input price |
$1.25/M |
$0.05/M |
| Output price |
$10.00/M |
$0.40/M |
| Cached input |
$0.3100/M |
$0.0050/M |
| Context window |
2.0M |
400K |
| Max output |
66K |
64K |
| Modalities |
text image audio video |
text |
| Tokenizer |
gemini |
o200k_base |
Capability matrix
| Capability | Gemini 2.5 Pro | GPT-5 Nano |
|---|
| function calling |
Yes |
Yes |
| json mode |
Yes |
Yes |
| vision |
Yes |
No |
| streaming |
Yes |
Yes |
| audio |
Yes |
No |
| video |
Yes |
No |
| thinking |
Yes |
No |
Benchmark comparison
Higher is better for all benchmarks shown.
Per-call cost on typical workloads
| Workload (in/out tokens) | Gemini 2.5 Pro | GPT-5 Nano | Cheaper by |
|---|
| Standard chat (1K / 500) |
$0.006250 |
$0.000250 |
GPT-5 Nano by $0.006000 |
| RAG (4K / 500) |
$0.010000 |
$0.000400 |
GPT-5 Nano by $0.009600 |
| Long doc (20K / 1K) |
$0.035000 |
$0.001400 |
GPT-5 Nano by $0.033600 |
| Very long context (100K / 2K) |
$0.140000 |
$0.005600 |
GPT-5 Nano by $0.134400 |
When to choose Gemini 2.5 Pro over GPT-5 Nano
- Larger context window (2.0M vs 400K) — relevant when whole documents or long histories must fit in a single call.
- Supports vision — GPT-5 Nano does not.
- Supports audio — GPT-5 Nano does not.
- Supports video — GPT-5 Nano does not.
- Supports thinking — GPT-5 Nano does not.
When to choose GPT-5 Nano over Gemini 2.5 Pro
- Per-token input cost is 96% lower than Gemini 2.5 Pro.
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