GPT-5.6 pricing, across all three tiers.
Sol at $4 and $20, Terra at $2 and $12, Luna at $0.20 and $1.20. A twenty-fold spread inside one model family, which makes tier choice the decision that matters.
GPT-5.6 ships as three tiers rather than one model, and the spread between them is larger than the gap between most providers: Sol costs twenty times Luna on input and roughly seventeen times on output. Picking the family is easy. Picking the tier is the decision that actually determines your bill, and it is the one most teams make once, at the top, and never revisit.
The tiers are also the migration target OpenAI names for a large batch of retiring models. o1, o1-pro, o3-mini, o4-mini and the legacy GPT-4 and GPT-3.5 snapshots all shut down on 23 October 2026, and the deprecation notice points at this family. If you are arriving here from one of those, note that o3-mini was a reasoning model at $1.10 and $4.40, so Terra is the closer match on price and Luna is a substantial saving if your task tolerates it.
One thing to carry over from the reasoning models: intermediate reasoning is billed as output whether or not you see it. Estimating output volume from the length of the answers you expect will understate the bill on any tier that reasons before it answers. Measure billed tokens on a real sample rather than estimating from response length.
- Sol, the escalation path for calls where a cheaper tier already failed validation
- Terra, the closest like-for-like replacement for the retiring o3-mini and o4-mini
- Luna, high-volume classification and extraction where the twenty-fold saving compounds
GPT-5.6 Sol vs the alternatives.
| Model | Input / 1M | Output / 1M | Sample request |
|---|---|---|---|
| GPT-5.6 Sol | $4.00 | $20.00 | $0.0128 |
| GPT-5 | $1.25 | $10.00 | $0.0055 |
| Claude Sonnet 5 | $2.00 | $10.00 | $0.0064 |
Common questions.
How much does GPT-5.6 cost per million tokens?
It depends on the tier. Sol is $4 input and $20 output, Terra is $2 and $12, and Luna is $0.20 and $1.20. The prices above show the Sol tier; use the calculator with your own token volumes to compare all three on your actual usage.
Which GPT-5.6 tier should I use?
Start at Luna or Terra and escalate rather than starting at Sol. Sol is twenty times Luna on input, so routing everything through the top tier is the most common way teams overspend on this family. The usual pattern is a cheap default with escalation on low confidence or a failed validation.
Is GPT-5.6 the replacement for o3-mini?
Yes. OpenAI points migrations from o1, o1-pro, o3-mini, o4-mini and the legacy GPT-4 and GPT-3.5 snapshots at the GPT-5.6 family, ahead of their shutdown on 23 October 2026. On price, Terra at $2 and $12 is the nearest tier to o3-mini at $1.10 and $4.40.
Is GPT-5.6 cheaper than GPT-5?
No. GPT-5 is $1.25 input and $10 output, which is cheaper than every GPT-5.6 tier except Luna. If cost is the constraint and GPT-5 meets your quality bar, it remains the cheaper choice.
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