GPT-5.6 Sol — API Pricing & Benchmarks
GPT-5.6 Sol is OpenAI's previous-generation reasoning model, released in 2026-07. The API costs $4.00 per 1M input tokens and $20.0 per 1M output tokens ($8.00 blended at a 3:1 ratio), with cached input at $0.40. It supports a 1.1M-token context window. On the independently measured Artificial Analysis Intelligence Index it scores 47, ranking #8 of 72 models tracked on this site, with a median output speed of 58 tokens/sec. Pricing was cut on 2026-08-21 (previously $5.00/$30.0 per 1M tokens).
Explore provider routes and additional benchmark sources for GPT-5.6 Sol
| Provider | OpenAI |
| Input price / 1M tokens | $4.00 |
| Output price / 1M tokens | $20.0 |
| Cached input / 1M tokens | $0.40 |
| Blended price (3:1) | $8.00 |
| Context window | 1.1M |
| Max output tokens | 128K |
| Knowledge cutoff | 2026-02 |
| License | proprietary |
| Input modalities | T+I |
| Output speed (tok/s) | 58 |
| Released | 2026-07 |
| Artificial Analysis Intelligence Index | 47 |
| LMArena Elo | 1455 |
| GPQA Diamond | 94.1% |
| Humanity's Last Exam | 49.5% |
Where GPT-5.6 Sol fits
On a blended 3:1 basis GPT-5.6 Sol costs $8.00 per 1M tokens, cheaper than 13% of the 84 priced models in this index. It is a previous-generation model: usually only worth choosing if you have an existing integration, negotiated pricing, or need its specific behavior, since newer siblings offer better price-performance. Measured output speed of 58 tokens/sec is below the index median of 107 — typical of reasoning-heavy models, and worth checking against interactive latency budgets. Cached input is priced at $0.40 (90% below standard input), which rewards prompt structures with long stable prefixes — see our caching guide.
Price history
| Period | Input $/1M | Output $/1M | Cached $/1M |
|---|---|---|---|
| 2026-07-18 → 2026-08-21 | $5.00 | $30.0 | $0.50 |
| 2026-08-21 → current | $4.00 | $20.0 | $0.40 |
List-price changes recorded by this site. The full dataset is public: price-history.json (CC BY 4.0).
Alternatives at a similar price
- Claude Opus 5.5 (Anthropic) — $8.00/1M blended, AA Index 57.6
- Claude Opus 5 (Anthropic) — $10.0/1M blended, AA Index 50.8
- Claude Opus 4.8 (Anthropic) — $10.0/1M blended, AA Index 41.8
- Claude Opus 4.7 (Anthropic) — $10.0/1M blended, AA Index 40.7
Compare GPT-5.6 Sol
About OpenAI
OpenAI builds the GPT series. The GPT-6 generation (September 2026) ships in three sizes — Astra (flagship, $10/$50), Sol ($2/$10) and Luna ($0.10/$0.50) — that share a 1.05M-token context window and the same tooling, so teams can move workloads between price points without changing integration code. The GPT-5.6 models remain on sale as the previous generation.