Gemini 3.1 Pro vs GPT-6 Astra
Gemini 3.1 Pro costs $2.00 / $12.00 and GPT-6 Astra costs $10.00 / $50.00 per million input / output tokens. At a typical 3:1 mix, Gemini 3.1 Pro is 4.4× cheaper than GPT-6 Astra. But GPT-6 Astra scores clearly higher on Epoch AI’s Capabilities Index (169 vs 156, beyond the margin of error).
Price
Gemini 3.1 Pro is 4.4× cheaper per token
On a coding agent: $533 vs $2,598 a month (5× less)
Capability
GPT-6 Astra scores higher
Gemini 3.1 Pro 156 (155–158)
GPT-6 Astra 169 (166–173)
GPT-6 Astra 169 (166–173)
Best value at GPT-6 Astra’s level
GPT-6.1 Terra, 12× less
Level with or above GPT-6 Astra · $213 a month on a coding agent · Every option
Input
$2.00
per 1M
Output
$12.00
per 1M
Cached
$0.20
1M context
Input
$10.00
per 1M
Output
$50.00
per 1M
Cached
$1.00
1.05M context
Side by side
✓ marks the cheaper price, larger context window, bigger discount or higher score.
| Detail | Gemini 3.1 Pro | GPT-6 Astra |
|---|---|---|
| Price per 1M tokens | ||
| Input | $2.00Lowest | $10.00 |
| Output | $12.00Lowest | $50.00 |
| Blended (3 in : 1 out) | $4.50Lowest | $20.00 |
| Cached input | $0.20Lowest | $1.00 |
| Batch or off-peak discount | 50% (batch) | 50% (batch) |
| Long prompts | Over 200K: $4 / $18 | Over 272K: 2× in, 1.5× out |
| Limits and model | ||
| Context window | 1M | 1.05MLargest |
| Capability score Epoch AI index | 156 | 169Highest |
| Arena text score 25 Sep 2026 | 1487Highest | 1478 |
| Released | Feb 2026 | 3 Sep 2026 |
| Open weights | No | No |
| Status | Current | Current |
| Checked | ||
| Price checked | 6 Nov 2026 Gemini API pricing | 2 Nov 2026 OpenAI pricing |
Monthly cost on three workloads
List prices, no batch discount. The cached share applies where a model has a cache rate.
| Workload | Gemini 3.1 Pro | GPT-6 Astra | Difference |
|---|---|---|---|
| Customer chat assistant50,000 conversations a month, about 2,000 tokens in and 400 out each; 50% cachedPrice this workload in the calculator | $350Lower | $1,550 | $1,200 |
| Document Q&A (RAG)20,000 questions a month over retrieved documents, 12,000 in and 600 out; 30% cachedPrice this workload in the calculator | $494Lower | $2,352 | $1,858 |
| Coding agent400 tasks a month, 40 steps each with a growing context; 85% cachedPrice this workload in the calculator | $449Lower | $2,163 | $1,714 |
How they differ
- Gemini 3.1 Pro is cheaper on input ($2 vs $10).
- Gemini 3.1 Pro is cheaper on output ($12 vs $50), which matters most for long answers and reasoning models.
- GPT-6 Astra accepts longer prompts (1.05M vs 1M tokens).
- Cached input is cheaper on Gemini 3.1 Pro ($0.20 vs $1), which favours agents and chat apps that resend the same context.
- On Epoch AI’s Capabilities Index, GPT-6 Astra scores clearly higher (169 vs 156), beyond the margin of error.
- On the Arena text leaderboard (25 Sep 2026), Gemini 3.1 Pro scores higher (1487 vs 1478). Test both on your own prompts before deciding.
Recent changes
All changes- OpenAI launched GPT-6.1 Terra at $1 / $5 per 1M tokens, with cached input at $0.05: half the price of GPT-6.1 Sol.
- Gemini 4 Argon reached the paid Gemini API at an introductory $2 / $10 per 1M tokens, with cache reads at $0.10, until 30 November 2026; from 1 December it costs $4 / $20.
- GPT-6.1 Sol replaced GPT-6 Sol at the same $2 / $10 per 1M tokens, with cached input cut from $0.20 to $0.10.
- OpenAI launched GPT-6 Sol at $2 / $10 and GPT-6 Luna at $0.10 / $0.50.
- OpenAI launched GPT-6 Astra at $10 / $50, its most expensive standard model.
