GPT-6.1 Terra vs GPT-6 Sol
OpenAI · US | OpenAI · US · Updated June 2026
Quick verdict
Both are OpenAI models. GPT-6.1 Terra is the newer, generally stronger default; reach for GPT-6 Sol when a specific cost or latency profile matters more than the latest capabilities.
GPT-6.1 Terra and GPT-6 Sol are both OpenAI models, so the real question is not which lab to trust but which tier fits your workload and budget. GPT-6.1 Terra is openAI's October 26, 2026 mid-tier model - a 1.05M-context, computer-use-capable GPT at $1/$5 per million tokens, half the price of its predecessor. GPT-6 Sol is openAI's September 22, 2026 mid-tier update — Astra-derived improvements at half the GPT-5.6 Sol price, $2/$10 per million tokens. Since both come from the same lab, the comparison below focuses on the tier-and-cost trade-offs that actually separate them.
Key differences at a glance
- ▸Price: GPT-6.1 Terra is about 2× cheaper on input ($1/$5 per 1M tokens vs $2/$10 per 1M tokens) — meaningful once you are processing millions of tokens a month.
- ▸Context window: both advertise 1.05M tokens (~1,575 pages). Tie on paper — test on your own long inputs, since usable recall varies by model.
- ▸Recency: GPT-6.1 Terra is the newer model by about 34 days (released October 26, 2026), usually meaning fresher training data and capabilities.
Side-by-side specs
| Spec | GPT-6.1 Terra | GPT-6 Sol |
|---|---|---|
| Provider | OpenAI (US) | OpenAI (US) |
| Released | October 26, 2026 | September 22, 2026 |
| Context window | 1.05M tokens (~1,575 pages) | 1.05M tokens (~1,575 pages) |
| Price (in/out) | $1/$5 per 1M tokens | $2/$10 per 1M tokens |
| Open weight? | No — API only | No — API only |
| Modalities | text, image, code | text, image |
| SWE-Bench Verified | Not published | Not published |
| MRCR v2 @ 1M | Not published | Not published |
Who wins what
$1/$5 per million tokens (cached input $0.05) - half the price of GPT-6.1 Sol and GPT-5.6 Terra
GPT-6.1 Terra
At $1/$5 per 1M tokens it undercuts GPT-6 Sol ($2/$10 per 1M tokens), and that gap compounds at volume.
Terminal-Bench 4.0 of 50.3% at maximum reasoning effort, versus 21.5% for GPT-5.6 Terra (OpenAI-reported)
GPT-6.1 Terra
GPT-6 Sol is comparatively weak here — more reasoning capability than sibling GPT-6 Luna, but still positioned below flagship GPT-6 Astra
1.05M-token context with up to 128K output tokens, plus image input and computer use via the Responses API
GPT-6.1 Terra
OpenAI's October 26, 2026 mid-tier model - a 1.05M-context, computer-use-capable GPT at $1/$5 per million tokens, half the price of its predecessor — and it runs cheaper at $1/$5 per 1M tokens.
OpenAI's everyday-work tier below GPT-6 Astra, built with the same methods that improved Astra's professional work, factuality, coding, computer use, and alignment
GPT-6 Sol
GPT-6.1 Terra is comparatively weak here — openAI still positions Sol and Astra as the higher-capability choices for demanding coding problems
OpenAI says it makes about half as many mistakes as GPT-5.6 Sol
GPT-6 Sol
GPT-6 Sol lists openAI says it makes about half as many mistakes as GPT-5.6 Sol among its strengths; GPT-6.1 Terra does not.
Priced at half of the GPT-5.6 Sol/Luna generation's rates ($2/$10 vs GPT-5.6 Sol's $5/$30)
GPT-6 Sol
GPT-6 Sol lists priced at half of the GPT-5.6 Sol/Luna generation's rates ($2/$10 vs GPT-5.6 Sol's $5/$30) among its strengths; GPT-6.1 Terra does not.
Lowest cost at scale
GPT-6.1 Terra
At $1/$5 per 1M tokens, it is the cheaper of the two — the gap dominates the bill on high-volume workloads.
Which should you pick?
A cost-sensitive startup shipping high volume
→ GPT-6.1 Terra
At $1/$5 per 1M tokens it undercuts GPT-6 Sol, and on millions of tokens that margin decides the monthly bill.
Anyone whose priority is $1/$5 per million tokens (cached input $0.05) - half the price of gpt-6.1 sol and gpt-5.6 terra
→ GPT-6.1 Terra
It is specifically built for that.
Anyone whose priority is openai's everyday-work tier below gpt-6 astra, built with the same methods that improved astra's professional work, factuality, coding, computer use, and alignment
→ GPT-6 Sol
That is its strongest area.
GPT-6.1 Terra: where it fits
OpenAI's October 26, 2026 mid-tier model - a 1.05M-context, computer-use-capable GPT at $1/$5 per million tokens, half the price of its predecessor. Released October 26, 2026 by OpenAI, it is built for $1/$5 per million tokens (cached input $0.05) - half the price of GPT-6.1 Sol and GPT-5.6 Terra, terminal-Bench 4.0 of 50.3% at maximum reasoning effort, versus 21.5% for GPT-5.6 Terra (OpenAI-reported), 1.05M-token context with up to 128K output tokens, plus image input and computer use via the Responses API, and error rate on OpenAI's hard-prompt set falls from 53.6% (GPT-5.6 Terra) to 16.7% at low effort and 4.3% at max effort.
Its trade-offs are real: openAI still positions Sol and Astra as the higher-capability choices for demanding coding problems, requests above 272K input tokens are billed at 2x input and 1.5x output for the whole request, closed weights and no fine-tuning support, and benchmark figures are vendor-reported; no SWE-bench Verified or MRCR numbers published. At $1 in / $5 out per million tokens, it sits in the budget price band.
GPT-6 Sol: where it fits
OpenAI's September 22, 2026 mid-tier update — Astra-derived improvements at half the GPT-5.6 Sol price, $2/$10 per million tokens. Released September 22, 2026 by OpenAI, it is built for openAI's everyday-work tier below GPT-6 Astra, built with the same methods that improved Astra's professional work, factuality, coding, computer use, and alignment, openAI says it makes about half as many mistakes as GPT-5.6 Sol, priced at half of the GPT-5.6 Sol/Luna generation's rates ($2/$10 vs GPT-5.6 Sol's $5/$30), and 1.05M-token context window, input capped at 922K.
Its trade-offs: more reasoning capability than sibling GPT-6 Luna, but still positioned below flagship GPT-6 Astra, and cache-read pricing ($0.20/MTok) still costlier than Luna's ($0.01/MTok) for high-cache workloads. At $2 in / $10 out per million tokens, it sits in the mid price band.
The bottom line for this matchup
Because GPT-6.1 Terra and GPT-6 Sol come from the same lab (OpenAI), they share the same training philosophy and ecosystem — the decision is purely tier vs. cost. GPT-6.1 Terra is the more capable, more recent option; the other earns its place only when its price or latency profile fits a specific job better. Most teams should default to GPT-6.1 Terra and drop down only with a concrete reason.
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See pricingFrequently asked questions
Is GPT-6.1 Terra or GPT-6 Sol better for coding?
Public SWE-Bench figures are not available for either model, so the honest test is your own repository — run an identical real bug through both. By design, GPT-6.1 Terra leans toward $1/$5 per million tokens (cached input $0.05) - half the price of gpt-6.1 sol and gpt-5.6 terra while GPT-6 Sol leans toward openai's everyday-work tier below gpt-6 astra, built with the same methods that improved astra's professional work, factuality, coding, computer use, and alignment, and that positioning usually predicts which feels better on your codebase.
Which is cheaper, GPT-6.1 Terra or GPT-6 Sol?
GPT-6.1 Terra is cheaper — $1/$5 per 1M tokens vs $2/$10 per 1M tokens, roughly 2× apart on input.
Which has the bigger context window?
Both advertise 1.05M tokens (~1,575 pages). Remember advertised ≠ usable: recall typically degrades before the ceiling.
Should I upgrade from GPT-6 Sol to GPT-6.1 Terra?
Since both are OpenAI models, the newer one (GPT-6.1 Terra) is usually the better default unless you need a specific cost or latency profile from the other.
Which is newer, GPT-6.1 Terra or GPT-6 Sol?
GPT-6.1 Terra — released October 26, 2026, about 34 days after GPT-6 Sol.
Related comparisons
Specifications and benchmarks reflect publicly reported figures as of June 2026 and may change as providers release updates. Always verify on your own workload.