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Model board / GPT-5.6 Sol

GPT-5.6 Sol

previous OpenAI

Verified 2026-10-22 against the pages listed below. Prices are USD per 1M tokens, list rate — no committed-use, enterprise or volume discount.

Input
$4.00
Cached input
$0.4
Cache write
$5.00
Output
$20.00
Context window
1,050,000
Max output
128,000
Weights
closed
Caching
both

cut on 2026-08-22 from $5.00/$0.50/$6.25/$30.00, and labelled promotional "at least through November 21, 2026". Above 272K input tokens the whole request bills at 2x input and 1.5x output — $8.00/$0.80/$10.00/$30.00 — now stated on the model's own page

cached input at 10% of base; implicit mode places the breakpoint for you, explicit-only mode lets you place it, and an entry lives at least 30 minutes after its last write or reuse

Watch out

Superseded twice over: GPT-6 Sol is $2.00/$10.00, half this row, and OpenAI's models page now recommends GPT-6 Sol where it used to name GPT-5.6. This row's $4.00/$20.00 is still promotional through at least 2026-11-21 — so the older model is both the dearer one and the one on a clock

What we would use it for

The hardest reasoning and longest agent runs, where an eval already signed off on 5.6

What this has cost, week by week

Output price at each refresh since 2026-07-30. A vendor change is the provider changing its price. Our correction means this board changed what it prints and the provider's charge did not move — the two are never merged, because publishing the second as the first would be a price rise that never happened.

07-30 $30.00→08-06 $30.00→08-14 $30.00→08-20 $30.00→08-27 $20.00→09-03 $20.00→09-10 $20.00→09-17 $20.00→09-24 $20.00→10-01 $20.00→10-08 $20.00→10-15 $20.00→10-22 $20.00
our correction2026-08-06 · cache_write — As above — the page stated the cache-write rate and the board had carried null.
vendor change2026-08-27 · in, cached_in, cache_write, out — OpenAI cut Sol from $5.00/$0.50/$6.25/$30.00 to $4.00/$0.40/$5.00/$20.00. The pricing page carries no announcement date, so this is recorded on the date the board observed it.

Where these numbers came from

No number on this page was written that was not read from one of those pages on 2026-10-22. If one is wrong, send us the source URL and it is corrected in the next weekly refresh, with a changelog line saying what was wrong — contact@naderu.com.

Discussed in Naderu Weekly

The rest of the board

This row sits alongside 76 others on the model board, refreshed every week. The same data as JSON, and the terms for using it, are at /board-data.