Gemini 2.5 Flash vs GPT-5.6 Terra: pricing and benchmarks
Gemini 2.5 Flash is 85% cheaper on input tokens ($0.30 vs $2.00 per 1M). Gemini 2.5 Flash is 79% cheaper on output tokens ($2.50 vs $12.00 per 1M). On our document Q&A workload (50,000 questions a month), Gemini 2.5 Flash costs $195.00 a month versus $1,160 for GPT-5.6 Terra, 83% less. GPT-5.6 Terra scores 159.1 on the Epoch Capabilities Index vs 140.5 for Gemini 2.5 Flash.
Prices verified September 14, 2026.
Which should you choose?
GPT-5.6 Terra scores 159.1 on the Epoch Capabilities Index vs 140.5 for Gemini 2.5 Flash.
Gemini 2.5 Flash costs $0.85 per 1M tokens (3:1 input-to-output mix) vs $4.50 for GPT-5.6 Terra, 81% less.
A trade-off: GPT-5.6 Terra is 18.6 ECI points more capable but costs 5.3x as much as Gemini 2.5 Flash.
Pricing and specs
| Gemini 2.5 Flash | GPT-5.6 Terra | |
|---|---|---|
| Provider | OpenAI | |
| API model ID | gemini-2.5-flash | gpt-5.6-terra |
| Input / 1M tokens | $0.30 | $2.00 |
| Cached input / 1M tokens | $0.03 | $0.20 |
| Output / 1M tokens | $2.50 | $12.00 |
| Long-context rates | — | $4.00 in / $18.00 out on long-context requests |
| Context window | 1.05M tokens | 1.05M tokens |
| Max output | 66K tokens | 128K tokens |
| Batch discount | — | 50% off |
Benchmarks
| Gemini 2.5 Flash | GPT-5.6 Terra | |
|---|---|---|
| Epoch Capabilities Index | 140.5 | 159.1 |
| GPQA Diamond· Science reasoning | — | 91.1% |
| FrontierMath (Tiers 1–3)· Advanced math | — | 86.0% |
| SimpleQA Verified· Factual accuracy | — | 43.2% |
| ARC-AGI-2· Abstract reasoning | — | 83.9% |
| DeepSWE· Coding | — | 69.6% |
| APEX-Agents· Agentic work | 1.8% | — |
Source: Epoch AI, best recorded result per model (CC BY 4.0). A dash means no published score. See all benchmarks
Monthly cost for real workloads
| Workload | Gemini 2.5 Flash | GPT-5.6 Terra | Difference |
|---|---|---|---|
Support chatbot 100,000 replies a month, ~1,500 input tokens (system prompt + history) and ~400 output tokens each. | $145.00 | $780.00 | Gemini 2.5 Flash 81% cheaper |
Document Q&A (RAG) 50,000 questions a month with ~8,000 tokens of retrieved context and ~600 output tokens each. | $195.00 | $1,160 | Gemini 2.5 Flash 83% cheaper |
Coding agent 10,000 agent steps a month, ~40,000 input tokens each (70% read from the prompt cache) and ~2,000 output tokens. | $94.40 | $536.00 | Gemini 2.5 Flash 82% cheaper |
Estimates use standard list prices and ignore cache-write surcharges. Different tokenizers can count the same text differently, so test with your own prompts.
Gemini 2.5 Flash vs GPT-5.6 Terra cost calculator
- $195.00/mo$0.0039 / request
- GPT-5.6 TerraOpenAI$1,160/mo$0.02 / request
Standard-tier list prices. Long-context rates apply automatically where the provider publishes a threshold. Excludes cache-write surcharges, taxes, batch and volume discounts.
Gemini 2.5 Flash pricing notes
Google’s previous-generation Flash model.
- Audio input costs $1.00 per 1M tokens; text, image and video cost $0.30.
- Output price includes thinking tokens.
GPT-5.6 Terra pricing notes
The GPT-5.6 model that balances intelligence and cost.
- Cache writes are billed at $2.50 per 1M tokens.
- Fast mode costs 2x the standard rate; Flex costs half.
Frequently asked questions
- Is Gemini 2.5 Flash cheaper than GPT-5.6 Terra?
- Gemini 2.5 Flash is 85% cheaper on input tokens ($0.30 vs $2.00 per 1M). Gemini 2.5 Flash is 79% cheaper on output tokens ($2.50 vs $12.00 per 1M). On our document Q&A workload (50,000 questions a month), Gemini 2.5 Flash costs $195.00 a month versus $1,160 for GPT-5.6 Terra, 83% less.
- Which is more capable, Gemini 2.5 Flash or GPT-5.6 Terra?
- GPT-5.6 Terra scores 159.1 on the Epoch Capabilities Index vs 140.5 for Gemini 2.5 Flash.
- How much does Gemini 2.5 Flash cost per 1M tokens?
- Gemini 2.5 Flash costs $0.30 per 1M input tokens and $2.50 per 1M output tokens, and $0.03 per 1M cached input tokens on Google’s standard tier.
- How much does GPT-5.6 Terra cost per 1M tokens?
- GPT-5.6 Terra costs $2.00 per 1M input tokens and $12.00 per 1M output tokens, and $0.20 per 1M cached input tokens on OpenAI’s standard tier.
- Which has the larger context window, Gemini 2.5 Flash or GPT-5.6 Terra?
- GPT-5.6 Terra has the larger context window: 1.05M tokens versus 1.05M for Gemini 2.5 Flash.