Gemini 3.1 Pro Preview Custom Tools vs GPT-5 Image
GPT-5 Image costs 1.2x less per output token than Gemini 3.1 Pro Preview Custom Tools ($10.00 vs $12.00 per million). Updated October 21, 2026; no benchmark has tested both models yet.
- Coding
- No data
- Overall
- No data
- Output $/M
- $12.00
- Coding
- No data
- Overall
- No data
- Output $/M
- $10.00
Gemini 3.1 Pro Preview Custom Tools or GPT-5 Image: which to pick
Neither model has a coding score yet, so the two cannot be ranked on coding.
Pick Gemini 3.1 Pro Preview Custom Tools for a larger context window (1.05M against 400K tokens).
No benchmark has tested both yet. Gemini 3.1 Pro Preview Custom Tools has results on Vending-Bench 2; GPT-5 Image on Design Arena: images, Design Arena: graphic design and Design Arena: logos. Compare them on price and context instead.
Which one for your work
Each card is decided by one number both models carry. Where only one has it, the card says so and makes no call.
Coding
Vibe Coding Index, six public coding benchmarks
No call
Neither has a coding score yet.
One side not measured
Image generation
Design Arena: images
No call
Only GPT-5 Image has a Design Arena: images result, 1191.
Directional only
Long documents
Listed context window
Gemini 3.1 Pro Preview Custom Tools
Gemini 3.1 Pro Preview Custom Tools takes 1.05M tokens against 400K.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
Gemini 3.1 Pro Preview Custom Tools
Gemini 3.1 Pro Preview Custom Tools $0.0080, GPT-5 Image $0.015 per turn.
List prices
At a glance
- Coding index
- Gemini 3.1 Pro Preview Custom Tools not benchmarked, GPT-5 Image not benchmarked.
- Widest category
- None yet: no category has been tested on both models.
- Widest single gap
- None yet: no benchmark has tested both models.
- Output price
- Gemini 3.1 Pro Preview Custom Tools $12.00 against GPT-5 Image $10.00 per million output tokens, 1.2x apart.
- Context window
- Gemini 3.1 Pro Preview Custom Tools takes 1.05M tokens, GPT-5 Image 400K.
Benchmark by benchmark
Every board either model has a result on, a category to a fold; bars are each result on a 0 to 100 scale. Only one model is measured on each, so no row names a leader.
Agentic workDirectional onlyPublic boards, shown as published, kept out of the index1 board measured
| Benchmark | Gemini 3.1 Pro Preview Custom Tools | GPT-5 Image | Leader |
|---|---|---|---|
| Vending-Bench 2 | $3,774 | Not measured | Only Gemini 3.1 Pro Preview Custom Tools measured |
| Neither model has a result on the other 38 boards here | |||
Image generationDirectional onlyPublic boards, shown as published, kept out of the index3 boards measured
| Benchmark | Gemini 3.1 Pro Preview Custom Tools | GPT-5 Image | Leader |
|---|---|---|---|
| Design Arena: images | Not measured | 1191 | Only GPT-5 Image measured |
| Design Arena: graphic design | Not measured | 1172 | Only GPT-5 Image measured |
| Design Arena: logos | Not measured | 1202 | Only GPT-5 Image measured |
| Neither model has a result on the other 2 boards here | |||
What each workload costs
Three fixed token mixes at each model's listed price, so per-token rates become a bill.
Chat turn
1K input + 500 output tokens
Gemini 3.1 Pro Preview Custom Tools costs less
Repository review
50K input + 3K output tokens
Gemini 3.1 Pro Preview Custom Tools costs less
Agent loop
200K input + 10K output tokens
Gemini 3.1 Pro Preview Custom Tools costs less
Listed OpenRouter rates, without cache or batch discounts. A workload that does not fit a model's context window would need splitting.
Specification differences
The leading value in a row is marked; a row with a missing value names no leader. Our two rows are marked in red.
| Specification | Google Gemini 3.1 Pro Preview Custom Tools | OpenAI GPT-5 Image |
|---|---|---|
| Maker | OpenAI | |
| Weights | No public weights listed | No public weights listed |
| Released | February 25, 2026 | October 14, 2025 |
| Context window | 1.05M | 400K |
| Input $/Mtok | $2.00 | $10.00 |
| Output $/Mtok | $12.00 | $10.00 |
| Coding index | Not benchmarked | Not benchmarked |
| Independent measurements behind it | 0 | 0 |
| Cost per solved task | Not computable | Not computable |
| Source | OpenRouter listing | OpenRouter listing |
Questions
Is Gemini 3.1 Pro Preview Custom Tools better than GPT-5 Image for coding?
Neither model has a coding score yet, so the two cannot be ranked on coding. Pick Gemini 3.1 Pro Preview Custom Tools for a larger context window (1.05M against 400K tokens).
Which is cheaper, Gemini 3.1 Pro Preview Custom Tools or GPT-5 Image?
Gemini 3.1 Pro Preview Custom Tools costs $2.00 per million input tokens and $12.00 per million output tokens; GPT-5 Image costs $10.00 and $10.00. Cost per solved task is known for neither of them.
Which has the bigger context window, Gemini 3.1 Pro Preview Custom Tools or GPT-5 Image?
Gemini 3.1 Pro Preview Custom Tools, with 1.05M tokens against 400K.
Has any benchmark tested both Gemini 3.1 Pro Preview Custom Tools and GPT-5 Image?
No benchmark has tested both yet. Gemini 3.1 Pro Preview Custom Tools has results on Vending-Bench 2; GPT-5 Image on Design Arena: images, Design Arena: graphic design and Design Arena: logos. Compare them on price and context instead. Data as of October 21, 2026.