AIREITEROpenAI shipped GPT-5.6 in a late-June limited preview, and as of July 9, 2026 it's generally available — live across ChatGPT, Codex, ChatGPT Work, and the API. The lineup is three named tiers — Sol, Terra, and Luna — each with its own price, context window, and target workload, and this guide breaks down the official pricing for all three.
This guide uses OpenAI's own developer docs (linked at the end) to break down what each tier is for, what it costs versus GPT-5.5, how it differs, and how to access each one.
What is GPT-5.6?
GPT-5.6 is OpenAI's newest flagship series, and it drops the old mini / nano suffixes for three named tiers that signal intelligence, speed, and cost:
Sol — the flagship, tuned for complex coding, long-horizon agentic tasks, and safety research.
Terra — the balanced tier, positioned to match GPT-5.5's quality at roughly half the price.
Luna — the low-cost tier, built for fast, high-volume work like summarizing, drafting, and tagging.
OpenAI's preview announcement is titled "Previewing GPT-5.6 Sol," which tells you where the emphasis sits. Per OpenAI's developer docs, the latest models take text and image input, return text output, and support vision, served through the Responses API and the official SDKs. Note that image input means GPT-5.6 can read images — OpenAI has not announced native image generation for this series.
Sol, Terra, Luna: which tier to choose
The three tiers map to different jobs. OpenAI's docs also list two reasoning modes on top: max (more reasoning effort) and ultra (sub-agent collaboration for more complex multi-step workflows).
Here's the spec sheet, taken from OpenAI's developer model pages:
Tier | Model ID | Input ($/MTok) | Output ($/MTok) | Context | Max output | Knowledge cutoff |
|---|---|---|---|---|---|---|
Sol |
| $5.00 | $30.00 | 1M | 128K | Feb 16, 2026 |
Terra |
| $2.50 | $15.00 | 1M | 128K | Feb 16, 2026 |
Luna |
| $1.00 | $6.00 | 1M | 128K | Feb 16, 2026 |
Rules of thumb:
Pick Sol for hard engineering work — refactors, multi-step automation, agentic pipelines, or security research where accuracy matters more than cost.
Pick Terra when you want GPT-5.5-class quality for customer support, internal tools, or document analysis but need to control spend at scale.
Pick Luna for high-throughput, latency-sensitive jobs — batch first drafts, content tagging, summaries — where "good and fast" beats "best."
GPT-5.6 vs GPT-5.5: price and positioning
The clearest way to read GPT-5.6 is against GPT-5.5, which lists at $5 / $30 per million tokens (input / output) in the same docs:
GPT-5.5 | GPT-5.6 Terra | GPT-5.6 Sol | |
|---|---|---|---|
Input / Output ($/MTok) | $5 / $30 | $2.50 / $15 | $5 / $30 |
vs GPT-5.5 price | baseline | exactly half | same |
Context | 1M | 1M | 1M |
Positioning | Prior flagship | ≈5.5 quality | New flagship |
Best for | General reasoning/coding | Cost-sensitive scale | Hard coding, agentic |
GPT-5.6 doesn't raise the ceiling price — Sol matches 5.5 — it adds cheaper tiers underneath. Terra is the headline: half of GPT-5.5's rate, which OpenAI positions at 5.5-class quality (its own claim, not an independent benchmark). Sol sits above 5.5 on harder work — OpenAI cites gains on agentic and command-line coding and more token-efficient long-horizon tasks, though these are vendor figures with limited independent reproduction, so treat them as directional. So if you're on 5.5: Terra is the cost-down move, Sol is the capability-up move.
A concrete cost example — a task that sends 1M input tokens and returns 200K output tokens:
Tier | Input | Output | Total |
|---|---|---|---|
Sol | $5.00 | $6.00 | $11.00 |
Terra | $2.50 | $3.00 | $5.50 |
Luna | $1.00 | $1.20 | $2.20 |
The series also supports prompt caching, so reused context (cached input) is billed at a discount to the standard input rate. One correction worth flagging, because a wrong figure spread through early coverage: the repeated "1.5M token context" doesn't match the docs, which show a 1M context window across all three tiers — Sol, Terra, and Luna alike — with 128K max output.
Can you use GPT-5.6 yet?
Short answer: yes. After its late-June limited preview, GPT-5.6 reached general availability on July 9, 2026 and is live across ChatGPT, Codex, ChatGPT Work, and the API. Searches like "gpt 5.6 banned" were a misreading of the preview window — it was gated, not banned, and that gate is now lifted. Rollout is staged, so if a tier isn't showing on your account yet, that's the phased release rather than a block.
The series also ships with layered safety controls — model-level refusals, real-time detection, tiered access, and ongoing red-teaming. Combined with the gated preview it launched under, that's what fueled the earlier "is it restricted?" chatter.
How to access GPT-5.6
Start with the official check: list the models available to your account and see whether the gpt-5.6-* IDs come back.
curl https://api.openai.com/v1/models \
-H "Authorization: Bearer $OPENAI_API_KEY" | grep gpt-5.6
If gpt-5.6-sol / -terra / -luna appear, your account has them and you can call them via the Responses API or Codex. If you get an empty result — or a model_not_found / permission error — the staged GA rollout likely hasn't reached your account yet; GPT-5.5 is the closest drop-in fallback for anything you'd route to 5.6 Terra in the meantime.
FAQ
When will GPT-5.6 be available to everyone?
GPT-5.6 reached general availability on July 9, 2026 — it's live across ChatGPT, Codex, ChatGPT Work, and the API. Rollout is staged, so it may take a little time to appear on a given account.
Which tier should I default to?
Terra for most production traffic (5.5-class quality at half the price), Sol when accuracy on hard coding/agentic tasks outweighs cost, Luna for cheap high-volume drafting and tagging.
Does GPT-5.6 have a free tier?
No free API allowance — it's a paid API model. In ChatGPT it's on the paid plans (Plus, Pro, Business, Enterprise), not the free tier.
How is GPT-5.6 different from GPT-5.5?
Terra matches 5.5's quality for half the price, while Sol pushes ahead on coding and long-horizon agentic tasks. New max and ultra reasoning modes also debut here.
Can GPT-5.6 generate images?
It accepts image input (vision) but OpenAI has not announced native image generation for the 5.6 series.
Sources
OpenAI — Models (developer docs): https://developers.openai.com/api/docs/models
OpenAI — GPT-5.6 Sol model page (pricing, context, cutoff): https://developers.openai.com/api/docs/models/gpt-5.6-sol
OpenAI — GPT-5.6 Terra model page: https://developers.openai.com/api/docs/models/gpt-5.6-terra
OpenAI — GPT-5.6 Luna model page: https://developers.openai.com/api/docs/models/gpt-5.6-luna
OpenAI — GPT-5.5 model page (price baseline): https://developers.openai.com/api/docs/models/gpt-5.5
OpenAI — "Previewing GPT-5.6 Sol" announcement: https://openai.com/index/previewing-gpt-5-6-sol/
Pricing and specs verified against OpenAI's developer docs; availability updated for the July 9, 2026 general-availability launch (verified 2026-07-10).