Models, measured side by side
Gemini 2.5 Flash vs GPT-4o
Compare Gemini 2.5 Flash, GPT-4o by token pricing, context length, benchmark results, speed and tool support.
Monthly workload
Monthly cost breakdown
InputOutput
Gemini 2.5 Flash
$19 / mo
GPT-4o
$100 / mo
Performance comparison
Gemini 2.5 Flash
9.9
GPT-4o
8.4
Overview
Pricing & capacity
| Pricing & capacity | Gemini 2.5 Flash | GPT-4o |
|---|---|---|
| Input / 1M tokens | $0.30 | $2.50 |
| Output / 1M tokens | $2.50 | $10 |
| Cached input / 1M | $0.03 | $1.25 |
| Monthly cost | $19 | $100 |
| Context window | 1M | 128K |
| Maximum output | 66K | 16K |
Input / 1M tokens
- Gemini 2.5 Flash
- $0.30
- GPT-4o
- $2.50
Output / 1M tokens
- Gemini 2.5 Flash
- $2.50
- GPT-4o
- $10
Cached input / 1M
- Gemini 2.5 Flash
- $0.03
- GPT-4o
- $1.25
Monthly cost
- Gemini 2.5 Flash
- $19
- GPT-4o
- $100
Context window
- Gemini 2.5 Flash
- 1M
- GPT-4o
- 128K
Maximum output
- Gemini 2.5 Flash
- 66K
- GPT-4o
- 16K
Benchmarks & performance
| Benchmarks & performance | Gemini 2.5 Flash | GPT-4o |
|---|---|---|
| Arena Elo | 1,200 | 1,178 |
| MMLU-Pro | 73.6% | 69.9% |
| Intelligence Index | 9.9 | 8.4 |
| GPQA | 68.3% | 54.3% |
| Humanity’s Last Exam | 4.7% | 2.4% |
| Output speed | 190 tokens/s | 145 tokens/s |
| Time to first token | 0.46 s | 0.84 s |
| DesignArena rating | 1,063 | 864 |
| DesignArena win rate | 45.4% | 34.8% |
Arena Elo
- Gemini 2.5 Flash
- 1,200
- GPT-4o
- 1,178
MMLU-Pro
- Gemini 2.5 Flash
- 73.6%
- GPT-4o
- 69.9%
Intelligence Index
- Gemini 2.5 Flash
- 9.9
- GPT-4o
- 8.4
GPQA
- Gemini 2.5 Flash
- 68.3%
- GPT-4o
- 54.3%
Humanity’s Last Exam
- Gemini 2.5 Flash
- 4.7%
- GPT-4o
- 2.4%
Output speed
- Gemini 2.5 Flash
- 190 tokens/s
- GPT-4o
- 145 tokens/s
Time to first token
- Gemini 2.5 Flash
- 0.46 s
- GPT-4o
- 0.84 s
DesignArena rating
- Gemini 2.5 Flash
- 1,063
- GPT-4o
- 864
DesignArena win rate
- Gemini 2.5 Flash
- 45.4%
- GPT-4o
- 34.8%
Tools & features
| Tools & features | Gemini 2.5 Flash | GPT-4o |
|---|---|---|
| Function calling | Supported | Supported |
| Structured outputs | Supported | Supported |
| JSON mode | Supported | Supported |
| Reasoning | Supported | Not listed |
| Built-in web search | Not listed | Supported |
| Log probabilities | Not listed | Supported |
| Deterministic seed | Supported | Supported |
| Prompt caching | Supported | Supported |
Function calling
- Gemini 2.5 Flash
- Supported
- GPT-4o
- Supported
Structured outputs
- Gemini 2.5 Flash
- Supported
- GPT-4o
- Supported
JSON mode
- Gemini 2.5 Flash
- Supported
- GPT-4o
- Supported
Reasoning
- Gemini 2.5 Flash
- Supported
- GPT-4o
- Not listed
Built-in web search
- Gemini 2.5 Flash
- Not listed
- GPT-4o
- Supported
Log probabilities
- Gemini 2.5 Flash
- Not listed
- GPT-4o
- Supported
Deterministic seed
- Gemini 2.5 Flash
- Supported
- GPT-4o
- Supported
Prompt caching
- Gemini 2.5 Flash
- Supported
- GPT-4o
- Supported
API & availability
| API & availability | Gemini 2.5 Flash | GPT-4o |
|---|---|---|
| API identifier | gemini-2.5-flash | gpt-4o |
| API providers | Google, Google, Google, Google AI Studio, Google AI Studio, Google, Google AI Studio | Azure, OpenAI |
| Knowledge cutoff | 2025-01-31 | 2023-10-31 |
| Prices checked | Oct 8, 2026 | Oct 8, 2026 |
API identifier
- Gemini 2.5 Flash
gemini-2.5-flash- GPT-4o
gpt-4o
API providers
- Gemini 2.5 Flash
- Google, Google, Google, Google AI Studio, Google AI Studio, Google, Google AI Studio
- GPT-4o
- Azure, OpenAI
Knowledge cutoff
- Gemini 2.5 Flash
- 2025-01-31
- GPT-4o
- 2023-10-31
Prices checked
- Gemini 2.5 Flash
- Oct 8, 2026
- GPT-4o
- Oct 8, 2026
About the models
Comparison FAQ
Gemini 2.5 Flash: $0.30 input and $2.50 output per million tokens. GPT-4o: $2.50 input and $10 output per million tokens. The cheaper choice depends on your input-to-output ratio; a model can have a lower input rate but a higher output rate.