GPT-5.6 Sol vs GPT-6.1 Terra: pricing and benchmarks
GPT-6.1 Terra is 75% cheaper on input tokens ($1.00 vs $4.00 per 1M). GPT-6.1 Terra is 75% cheaper on output tokens ($5.00 vs $20.00 per 1M). On our document Q&A workload (50,000 questions a month), GPT-6.1 Terra costs $550.00 a month versus $2,200 for GPT-5.6 Sol, 75% less. Epoch AI has not published a capability index score for GPT-6.1 Terra yet.
Which should you choose?
Epoch AI has not published a capability index score for GPT-6.1 Terra yet.
GPT-6.1 Terra costs $2.00 per 1M tokens (3:1 input-to-output mix) vs $8.00 for GPT-5.6 Sol, 75% less.
Pricing and specs
| GPT-5.6 Sol | GPT-6.1 Terra | |
|---|---|---|
| Provider | OpenAI | OpenAI |
| API model ID | gpt-5.6-sol | gpt-6.1-terra |
| Input / 1M tokens | $4.00 | $1.00 |
| Cached input / 1M tokens | $0.40 | $0.05 |
| Output / 1M tokens | $20.00 | $5.00 |
| Long-context rates | $8.00 in / $30.00 out on long-context requests | $2.00 in / $7.50 out above 272K prompt tokens |
| 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-6.1 Terra | |
|---|---|---|
| Epoch Capabilities Index | 161.7 | — |
| GPQA Diamond· Science reasoning | 93.5% | — |
| FrontierMath (Tiers 1–3)· Advanced math | 89.1% | — |
| SimpleQA Verified· Factual accuracy | 69.7% | — |
| ARC-AGI-2· Abstract reasoning | 92.5% | — |
| DeepSWE· Coding | 72.7% | — |
| APEX-Agents· Agentic work | 51.4% | — |
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-6.1 Terra | Difference |
|---|---|---|---|
Support chatbot 100,000 replies a month, ~1,500 input tokens (system prompt + history) and ~400 output tokens each. | $1,400 | $350.00 | GPT-6.1 Terra 75% cheaper |
Document Q&A (RAG) 50,000 questions a month with ~8,000 tokens of retrieved context and ~600 output tokens each. | $2,200 | $550.00 | GPT-6.1 Terra 75% 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 | $234.00 | GPT-6.1 Terra 76% cheaper |
Cached chatbot The same 100,000-reply support chatbot, but 60% of each prompt (system prompt + conversation history) is served from the prompt cache. | $1,076 | $264.50 | GPT-6.1 Terra 75% cheaper |
Meeting notes 10,000 meetings a month summarized from ~12,000-token transcripts, ~1,000 output tokens each. | $680.00 | $170.00 | GPT-6.1 Terra 75% cheaper |
Bulk translation 200,000 short translations a month, ~800 input and ~800 output tokens each. | $3,840 | $960.00 | GPT-6.1 Terra 75% cheaper |
Content moderation 1,000,000 classifications a month, ~400 input tokens and ~80 output tokens each. | $3,200 | $800.00 | GPT-6.1 Terra 75% cheaper |
Article drafting 300 long-form articles a month written from a ~4,000-token brief and outline, ~5,000 output tokens each. | $34.80 | $8.70 | GPT-6.1 Terra 75% cheaper |
Code review bot 30,000 pull-request reviews a month, ~5,000 input tokens each (30% cached repository context) and ~700 output tokens. | $858.00 | $212.25 | GPT-6.1 Terra 75% cheaper |
Invoice extraction 100,000 documents a month parsed into structured JSON, ~1,200 input and ~250 output tokens each. | $980.00 | $245.00 | GPT-6.1 Terra 75% 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-6.1 Terra cost calculator
- $550.00/mo$0.01 / req
- GPT-5.6 SolOpenAI$2,200/mo$0.04 / req
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-6.1 Terra pricing notes
OpenAI’s fast, efficient GPT-6.1 model for visual reasoning, computer use and writing, at half GPT-6.1 Sol’s price.
- Cache writes are billed at $1.25 (30-minute) or $2.50 (12-hour) per 1M tokens.
- Prompts over 272K input tokens use the long-context rates.
- Fast mode costs 2x the standard rate; Flex costs half.
Frequently asked questions
- Is GPT-5.6 Sol cheaper than GPT-6.1 Terra?
- GPT-6.1 Terra is 75% cheaper on input tokens ($1.00 vs $4.00 per 1M). GPT-6.1 Terra is 75% cheaper on output tokens ($5.00 vs $20.00 per 1M). On our document Q&A workload (50,000 questions a month), GPT-6.1 Terra costs $550.00 a month versus $2,200 for GPT-5.6 Sol, 75% less.
- Which is more capable, GPT-5.6 Sol or GPT-6.1 Terra?
- Epoch AI has not published a capability index score for GPT-6.1 Terra yet.
- 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-6.1 Terra cost per 1M tokens?
- GPT-6.1 Terra costs $1.00 per 1M input tokens and $5.00 per 1M output tokens, and $0.05 per 1M cached input tokens on OpenAI’s standard tier.
- Which has the larger context window, GPT-5.6 Sol or GPT-6.1 Terra?
- Both offer a 1.05M-token context window.