GPT-5.6 Sol vs GPT-5.6 Terra: pricing and benchmarks
GPT-5.6 Terra is 50% cheaper on input tokens ($2.00 vs $4.00 per 1M). GPT-5.6 Terra is 40% cheaper on output tokens ($12.00 vs $20.00 per 1M). On our document Q&A workload (50,000 questions a month), GPT-5.6 Terra costs $1,160 a month versus $2,200 for GPT-5.6 Sol, 47% less. Roughly tied. GPT-5.6 Sol scores 161.8 and GPT-5.6 Terra scores 159.1 on the Epoch Capabilities Index, and their confidence intervals overlap.
Prices verified September 14, 2026.
Which should you choose?
Roughly tied. GPT-5.6 Sol scores 161.8 and GPT-5.6 Terra scores 159.1 on the Epoch Capabilities Index, and their confidence intervals overlap.
GPT-5.6 Sol scores 72.7% on DeepSWE vs 69.6% for GPT-5.6 Terra.
GPT-5.6 Sol scores 89.1% on FrontierMath (Tiers 1–3) vs 86.0% for GPT-5.6 Terra.
GPT-5.6 Terra costs $4.50 per 1M tokens (3:1 input-to-output mix) vs $8.00 for GPT-5.6 Sol, 44% less.
GPT-5.6 Terra delivers statistically similar overall capability for 44% less.
Pricing and specs
| GPT-5.6 Sol | GPT-5.6 Terra | |
|---|---|---|
| Provider | OpenAI | OpenAI |
| API model ID | gpt-5.6-sol | gpt-5.6-terra |
| Input / 1M tokens | $4.00 | $2.00 |
| Cached input / 1M tokens | $0.40 | $0.20 |
| Output / 1M tokens | $20.00 | $12.00 |
| Long-context rates | $8.00 in / $30.00 out on long-context requests | $4.00 in / $18.00 out on long-context requests |
| Context window | 1.05M tokens | 1.05M tokens |
| Max output | 128K tokens | 128K tokens |
| Batch discount | 50% off | 50% off |
Benchmarks
| GPT-5.6 Sol | GPT-5.6 Terra | |
|---|---|---|
| Epoch Capabilities Index | 161.8 | 159.1 |
| GPQA Diamond· Science reasoning | 91.3% | 91.1% |
| FrontierMath (Tiers 1–3)· Advanced math | 89.1% | 86.0% |
| SimpleQA Verified· Factual accuracy | 69.7% | 43.2% |
| ARC-AGI-2· Abstract reasoning | 92.5% | 83.9% |
| DeepSWE· Coding | 72.7% | 69.6% |
| APEX-Agents· Agentic work | 40.0% | — |
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 | GPT-5.6 Sol | GPT-5.6 Terra | Difference |
|---|---|---|---|
Support chatbot 100,000 replies a month, ~1,500 input tokens (system prompt + history) and ~400 output tokens each. | $1,400 | $780.00 | GPT-5.6 Terra 44% cheaper |
Document Q&A (RAG) 50,000 questions a month with ~8,000 tokens of retrieved context and ~600 output tokens each. | $2,200 | $1,160 | GPT-5.6 Terra 47% 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. | $992.00 | $536.00 | GPT-5.6 Terra 46% 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.
GPT-5.6 Sol vs GPT-5.6 Terra cost calculator
- $1,160/mo$0.02 / request
- GPT-5.6 SolOpenAI$2,200/mo$0.04 / 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.
GPT-5.6 Sol pricing notes
OpenAI’s flagship GPT-5.6 model for complex professional work.
- Promotional pricing, available at least through November 21, 2026.
- Cache writes are billed at $5 per 1M tokens.
- Regional (data residency) endpoints add a 10% uplift.
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 GPT-5.6 Sol cheaper than GPT-5.6 Terra?
- GPT-5.6 Terra is 50% cheaper on input tokens ($2.00 vs $4.00 per 1M). GPT-5.6 Terra is 40% cheaper on output tokens ($12.00 vs $20.00 per 1M). On our document Q&A workload (50,000 questions a month), GPT-5.6 Terra costs $1,160 a month versus $2,200 for GPT-5.6 Sol, 47% less.
- Which is more capable, GPT-5.6 Sol or GPT-5.6 Terra?
- Roughly tied. GPT-5.6 Sol scores 161.8 and GPT-5.6 Terra scores 159.1 on the Epoch Capabilities Index, and their confidence intervals overlap.
- How much does GPT-5.6 Sol cost per 1M tokens?
- GPT-5.6 Sol costs $4.00 per 1M input tokens and $20.00 per 1M output tokens, and $0.40 per 1M cached input tokens on OpenAI’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, GPT-5.6 Sol or GPT-5.6 Terra?
- Both offer a 1.05M-token context window.