GPT-5.6 Sol ChatGPT Update: Free Access Expands
OpenAI updated GPT-5.6 Sol for Plus and Pro, while Free and Go get Luna, unlimited text chats, and a Think button. See the pricing impact.
By AI Pricing Guru Editorial Team
AI Pricing Guru articles are maintained by the editorial workflow behind the site: daily pricing snapshots, provider source checks, and review passes for model launches, subscription limits, and billing changes.
TL;DR
- Plus and Pro users get the updated GPT-5.6 Sol in ChatGPT today, with more focused answers, stronger factual reliability, and a thinking-effort slider.
- GPT-5.6 Luna becomes the default for Free and Go users this week.
- Unlimited text chats and a Think button arrive for Free and Go next week, subject to abuse guardrails; limits remain for files, images, and other tools.
- OpenAI announced no ChatGPT subscription or API price change, and the Sol versions used by Work and Codex are not changing in this release.
Current API cost context for the models behind paid and free chat products
USD per 1M tokens. Input and output rates are charted separately.
Compare API cost with a flat-rate chat subscription
Assumes 75% input tokens and 25% output tokens using current per-million rates.
GPT-5.6 Luna
openai
$4.50
- Input share
- $1.50
- Output share
- $3.00
Gemini 3.6 Flash
$30.00
- Input share
- $11.25
- Output share
- $18.75
Claude Sonnet 5
anthropic
$40.00
- Input share
- $15.00
- Output share
- $25.00
GPT-5.6 Sol
openai
$112.50
- Input share
- $37.50
- Output share
- $75.00
Current API rates—the ChatGPT access update changes no token prices
| Model | Provider | Input / 1M | Cached / 1M | Output / 1M |
|---|---|---|---|---|
| GPT-5.6 Luna | openai | $0.2 | $0.02 | $1.20 |
| GPT-5.6 Terra | openai | $2.00 | $0.2 | $12.00 |
| GPT-5.6 Sol | openai | $5.00 | $0.5 | $30.00 |
| Gemini 3.6 Flash | $1.50 | $0.15 | $7.50 | |
| Claude Sonnet 5 | anthropic | $2.00 | $0.2 | $10.00 |
Built from pricing.json at publish time.
OpenAI is expanding ChatGPT access without raising the announced subscription prices. Plus and Pro users get an updated GPT-5.6 Sol today, while Free and Go users move to GPT-5.6 Luna this week and receive unlimited text chats next week.
This is a ChatGPT product update, not an API price cut. The live table, chart, and calculator above show current API rates only; software, automations, and customer-facing products still require separately billed API usage. Compare the maintained ChatGPT subscription pricing page with OpenAI API pricing before choosing a billing model.
What changed
| ChatGPT surface | New access | Timing |
|---|---|---|
| Plus and Pro | Updated GPT-5.6 Sol for Instant and deeper reasoning; new thinking-effort slider | August 6 |
| Free and Go default | GPT-5.6 Luna | Rolling out this week |
| Free and Go text | Unlimited text chats, subject to abuse guardrails | Starting next week |
| Free and Go reasoning | Think button gives Luna more time on harder questions | Starting next week |
| Files, images, and other tools | Existing limits still apply | No unlimited access announced |
| Work and Codex | Their GPT-5.6 Sol version is unchanged | No change |
The slider is available on ChatGPT web, mobile, and desktop. OpenAI says the same updated Sol now powers quick and deeper responses for Plus and Pro, reducing the feeling of switching between models with different styles.
Pricing impact
OpenAI announced no new subscription price, quota price, or API token rate. Free users receive the largest economic gain: ongoing Luna text chats move from a scarce allowance to unlimited access next week, although OpenAI retains abuse guardrails and keeps separate limits on tools.
Paid users receive a quality and control upgrade inside their existing plan. That can improve the value of Plus or Pro, but it does not make an upgrade automatically worthwhile. If the updated Sol works on your current tier and you do not hit capacity limits, keep the lower plan.
Subscriptions remain for human use inside ChatGPT. Use the subscription-versus-API calculator for your workload; do not treat unlimited Free text chats as authorization or infrastructure for a production application.
What OpenAI’s quality claims mean
OpenAI says GPT-5.6 Sol now gives more direct answers, uses tighter formatting, adapts detail to the question, and relies more effectively on sources involving dates, numbers, rules, and assumptions.
In an internal evaluation of financial, medical, and legal prompts, responses containing at least one factual error were 68% less common with the updated Sol and 62% less common with Luna than with GPT-5.5 Instant. Those are provider-reported relative reductions on one internal evaluation—not proof that either model is error-free or that the same improvement transfers to every task.
Who benefits—and who loses
Free and Go users benefit most because Luna becomes the default and text conversations stop hitting a normal usage cap next week. Students, occasional users, and anyone comparing free assistants gain a stronger reason to stay in ChatGPT.
Plus and Pro users gain more control over latency versus reasoning depth and a more consistent experience across quick and difficult questions. Competitors with free chat tiers lose a distribution advantage, although their tool quotas, model quality, privacy terms, and regional access can still differ.
Users who mainly need file analysis, image generation, or other tools should not read “unlimited” as unlimited ChatGPT. Those categories retain limits. Work and Codex users also receive no model change from this release.
What users and developers should do
- Free and Go users should wait for the Luna default this week and unlimited text plus Think next week before paying only to escape text limits.
- Plus and Pro users should test the slider on the same research, writing, and coding prompts at different effort levels.
- Verify important dates, figures, legal, medical, and financial claims even after the reported factuality improvement.
- Keep API budgets unchanged: this announcement does not alter API rates or grant backend usage.
- Compare free-chat alternatives on the Google AI pricing page and paid plans in our ChatGPT vs Claude pricing guide.
Developers who need a managed API control group can compare Novita’s available open-model routes. A managed endpoint does not reproduce ChatGPT’s product features or its new free allowance.
Affiliate disclosure: AI Pricing Guru may earn a commission from the sponsored Novita link at no extra cost to you. It does not affect this analysis.
Labs status
AI Pricing Guru Labs already includes GPT-5.6 Sol, Terra, and Luna in its fixed cost-per-task suite. This ChatGPT release changes the consumer chat experience, not the public API models used by Labs, so a rerun would test a different artifact and would not verify OpenAI’s internal factuality result.
Bottom line
OpenAI is using access, not a lower sticker price, to improve ChatGPT’s value. Plus and Pro get a more focused Sol with adjustable thinking today; Free and Go get Luna this week, then unlimited guarded text chats and a Think button next week.
Use the upgrade before changing plans, keep tool limits in mind, and separate ChatGPT access from API billing.
Sources: OpenAI’s official GPT-5.6 Sol and Free access announcement and accompanying GPT-5.6 August system card. Official access and pricing status checked August 6, 2026.