What Does GPT-5.6 Sol Cost?
GPT-5.6 Sol costs $4.00 per million input tokens and $20.00 per million output tokens. A million tokens in plus a million tokens out comes to $24.00 at those rates.
Sol sits near the top of OpenAI's current line. Only two models cost more: the flagship gpt-6-astra at $10.00 / $50.00, which launched in early September 2026 and prices at exactly 2.5x Sol on both sides, and the older gpt-5.5 at $5.00 / $30.00.
Every price on this page was checked on 16 September 2026 against OpenAI's and Anthropic's own pricing documentation. Where a vendor has not published a number, this page says so rather than guessing.
The bill is one half of the question. AI Perks tracks $7.7M in credits across 194 companies, which is the half that pays it.
GPT-5.6 Sol vs the Rest of the OpenAI Line
Sol is the priciest of the three tiers carrying the 5.6 name, and the third most expensive model OpenAI currently sells, behind gpt-6-astra and the older gpt-5.5. The Sol, Terra and Luna names replaced the older Instant, Thinking, mini and nano scheme in July 2026.
| Model | Input / 1M | Output / 1M | 1M in + 1M out | Output multiple |
|---|---|---|---|---|
| gpt-6-astra | $10.00 | $50.00 | $60.00 | 5.0x |
| gpt-5.6-sol | $4.00 | $20.00 | $24.00 | 5.0x |
| gpt-5.6-terra | $2.00 | $12.00 | $14.00 | 6.0x |
| gpt-5.6-luna | $0.20 | $1.20 | $1.40 | 6.0x |
| gpt-5.5 | $5.00 | $30.00 | $35.00 | 6.0x |
| gpt-5.4 | $2.50 | $15.00 | $17.50 | 6.0x |
| gpt-5.4-mini | $0.75 | $4.50 | $5.25 | 6.0x |
| gpt-5.4-nano | $0.20 | $1.25 | $1.45 | 6.25x |
The last two columns are ours, derived from the listed prices. Two things fall out of them.
Sol undercuts gpt-5.5. The older mid tier costs $5.00 / $30.00. Sol is 20% cheaper on input, 33% cheaper on output, and 31% cheaper on a balanced million-in, million-out job. There is no remaining cost argument for gpt-5.5.
Astra and Sol charge a tighter output multiple. Both bill output at 5x input. Every other model in OpenAI's current line runs 6x or higher, and the retiring gpt-5 models ran 8x. On output-heavy work, the real gap between Sol and the cheap tiers is narrower than the headline input prices imply.
One surcharge to plan around: on gpt-6-astra, context above 200,000 tokens is billed at $20.00 / $75.00. OpenAI has not published an equivalent long-context rate for Sol.
What Does Sol Cost Per Month at Real Volume?
A workload of 50 million input and 10 million output tokens a month costs about $400 on Sol. The figures below are our estimates, calculated from the listed prices at that fixed volume.
| Model | Monthly estimate | Relative to Sol |
|---|---|---|
| gpt-6-astra | $1,000 | 2.50x |
| gpt-5.6-sol | $400 | 1.00x |
| gpt-5.6-terra | $220 | 0.55x |
| gpt-5.6-luna | $22 | 0.06x |
| Claude Opus 5 | $500 | 1.25x |
| Claude Sonnet 5 | $200 | 0.50x |
Over twelve months that is $4,800 on Sol against $12,000 on Astra at identical volume. The $7,200 difference is roughly the size of a credit grant, which is why the tier decision and the credit question are the same decision. Start at getaiperks.com.
Sol vs Claude, and the Sonnet Price Rise That Never Happened
Sol at $4.00 / $20.00 is exactly 20% below Claude Opus 5 on both sides, and exactly 2x Claude Sonnet 5 on both sides.
| Model | Input / 1M | Output / 1M | 1M in + 1M out |
|---|---|---|---|
| Claude Fable 5.1 | $10.00 | $50.00 | $60.00 |
| Claude Mythos 5.1 | $10.00 | $50.00 | $60.00 |
| Claude Opus 5 | $5.00 | $25.00 | $30.00 |
| Claude Sonnet 5 | $2.00 | $10.00 | $12.00 |
| Claude Haiku 4.5 | $1.00 | $5.00 | $6.00 |
| Meta Muse Spark 1.1-1.3 | $1.25 | $4.25 | $5.50 |
The right-hand column is ours again, derived from the listed input and output prices. Note that OpenAI's flagship and Anthropic's top tier are priced identically at $10.00 / $50.00. Claude Opus 5 launched on 24 July 2026 at the same price as Opus 4.8, so that tier has not moved.
Here is the part almost nobody reported. Anthropic had scheduled Sonnet 5 to rise from $2/$10 to $3/$15 on 1 September 2026, then cancelled the increase. In Anthropic's own words: "The previously scheduled increase to $3/$15 per million input/output tokens on September 1, 2026 will not occur." The introductory price is now the standard price.
That changes the comparison materially. At the scheduled $3/$15, Sol would have been 1.33x Sonnet 5 on input. At the standing $2/$10, Sol is 2x. At the 50M / 10M volume above, the cancellation saves a Sonnet 5 user $100 a month and doubles Sol's monthly premium from $100 to $200.
Meta's Muse Spark line runs $1.25 / $4.25, with a Contributor tier at $0.10 / $0.20 where Meta trains on your prompts and completions, and Muse Image at $0.01 per image. Meta runs no startup credit program for Muse, so that bill is yours in full.
The 10 December Shutdown Reprices Older Apps
OpenAI shuts down API access to gpt-5, gpt-5-mini and gpt-5-nano on 10 December 2026, 85 days after this page was updated. Do not start new builds on them.
| Legacy model | 1M in + 1M out | Nearest current tier | New cost | Change |
|---|---|---|---|---|
| gpt-5 ($1.25/$10.00) | $11.25 | gpt-5.6-terra | $14.00 | +24% |
| gpt-5-mini ($0.25/$2.00) | $2.25 | gpt-5.6-luna | $1.40 | -38% |
| gpt-5-nano ($0.05/$0.40) | $0.45 | gpt-5.6-luna | $1.40 | +211% |
Those percentages are ours, derived from list prices on a balanced workload. The direction is not what teams expect. Migrating off gpt-5-mini is a price cut. Luna beats it on input and output both. Migrating off gpt-5-nano is a 3.1x increase, because nothing in the current line goes that cheap.
Budget for the nano case now rather than in December. AI Perks is where teams cover that kind of step change without repricing their product.
Which Tier Fits Which Workload?
Pick by output volume and error tolerance, not by benchmark chatter. These are cost-shape recommendations drawn from the prices above.
Choose gpt-5.6-luna ($0.20 / $1.20) for classification, routing, extraction, tagging and any high-volume job with short outputs. At $1.40 per balanced million, it is 17x cheaper than Sol.
Choose gpt-5.6-terra ($2.00 / $12.00) as the default production workhorse. It is 42% cheaper than Sol on a balanced million and is the natural landing spot for gpt-5 migrations.
Choose gpt-5.6-sol ($4.00 / $20.00) when Terra's output is not good enough for a user-facing surface and Astra is overkill. Sol's honest niche is the top of the 5.6 family at 40% of the flagship's price.
Choose gpt-6-astra ($10.00 / $50.00) only for work where a rerun costs more than the token premium, and watch the 200k long-context threshold, which lifts it to $20.00 / $75.00.
The cheapest tier that clears your quality bar wins, and the way to find that bar is to test all four rather than reason about them. That testing is what credits are for, and getaiperks.com tracks $7.7M of them across 194 companies.
What the Vendors Have Not Published
Several numbers you will see quoted elsewhere for these models are not in any vendor's documentation, so they are not on this page.
- xAI and Grok token prices. Public sources conflict badly. Pricing varies by model and the only reliable figure is the one in xAI's own console.
- Google Gemini prices. Not verified in this research, so Gemini is omitted from every table above rather than estimated.
- Benchmark scores and capability rankings. No MMLU, HumanEval or SWE-bench figure for Sol has been verified here.
- Context window sizes. The only context figure confirmed is OpenAI's 200,000-token pricing threshold on gpt-6-astra.
- Rate limits and free-tier ceilings. Not published in the pricing documentation for any provider listed here.
Frequently Asked Questions
How much does GPT-5.6 Sol cost per million tokens?
GPT-5.6 Sol costs $4.00 per million input tokens and $20.00 per million output tokens, verified against OpenAI's pricing documentation on 16 September 2026. A balanced million in and million out runs $24.00. Credits that cover that bill are tracked at getaiperks.com.
Is GPT-5.6 Sol cheaper than gpt-6-astra?
Yes, by a factor of exactly 2.5 on both input and output. Astra costs $10.00 / $50.00 against Sol's $4.00 / $20.00. Astra also carries a long-context rate of $20.00 / $75.00 above 200,000 tokens, which Sol has no published equivalent for.
How does GPT-5.6 Sol compare to Claude?
Sol is 20% cheaper than Claude Opus 5 on both input and output, and exactly twice the price of Claude Sonnet 5 at $2.00 / $10.00. Anthropic cancelled the Sonnet 5 increase to $3/$15 that was scheduled for 1 September 2026, so that 2x gap is now permanent. See AI Perks for credits on both.
When does the old gpt-5 API shut down?
OpenAI shuts down API access to gpt-5, gpt-5-mini and gpt-5-nano on 10 December 2026. Migrating off gpt-5-mini to gpt-5.6-luna is roughly a 38% price cut by our estimate, while gpt-5-nano users face about a 3.1x increase, since nothing current is priced that low.
Which OpenAI model is cheapest right now?
gpt-5.6-luna at $0.20 per million input and $1.20 per million output is the cheapest model in OpenAI's current line, about $1.40 for a balanced million in and out. That is roughly 17x cheaper than Sol and 43x cheaper than gpt-6-astra on the same workload.
Can free credits cover a GPT-5.6 Sol bill?
Often entirely. At 50 million input and 10 million output tokens a month, Sol costs an estimated $400, which is $4,800 across a full year. Plenty of individual provider credit grants run well past that figure on their own. AI Perks tracks $7.7M in credits across 194 companies.
Verified prices, honest arithmetic, and the credits that cover the difference.