GPT-5.6 Terra vs GPT-5.6 Luna
Side-by-side comparison of API pricing, specs, benchmarks, and capabilities
| Specification |
by OpenAI
|
by OpenAI
|
|---|---|---|
| Overview | ||
| Status | Current flagship | Current mid tier |
| Released | Jul 9, 2026 | Jul 9, 2026 |
| Pricing per million tokens | ||
| Input | $2.00/Mtok | $0.200/Mtok |
| Output | $12.00/Mtok | $1.20/Mtok |
| Blended avg | $4.50/Mtok | $0.450/Mtok |
| Cached input | $0.200/Mtok | $0.020/Mtok |
| Specifications | ||
| Context window | 1M tokens | 1M tokens |
| Parameters | Proprietary | Proprietary |
| Speed (TPS) | — | — |
| Modalities | ||
| Input |
textimage
|
textimage
|
| Benchmarks source: Vellum LLM Leaderboard | ||
| Avg benchmark score | 87.7 | 90.7 |
| Perf / dollar | 19.5 | 201.6 |
| GPQA Diamond | 92.9 | 92.3 |
| Terminal-Bench 2.1 | 82.5 | 84.3 |
| SWE-Bench Verified | — | 93 |
| HumanEval | — | 93 |
| Independent composite scores each on its own scale — not part of the average above | ||
| AA Intelligence Index | 56.6 | 52.3 |
| AA Agentic Index | 50.2 | 46.9 |
| AA-Omniscience Index (−100–100) | 0.1 | -10.3 |
| GDPval-AA v2 | 1565.5 ELO | 1569.1 ELO |
| Providers | ||
| Available from |
OpenAI — $2.00/$12.00/Mtok
|
OpenAI — $0.200/$1.20/Mtok
|
Cost at scale
1M tokens · 50/50 input/output| Volume | GPT-5.6 Terra | GPT-5.6 Luna | Savings |
|---|---|---|---|
| 1M tokens | $4.5 | $0.45 | $4.05 (90%) |
| 10M tokens | $45 | $4.5 | $40.5 (90%) |
| 100M tokens | $450 | $45 | $405 (90%) |
| 1000M tokens | $4500 | $450 | $4050 (90%) |
When to pick which
distilled from the pricing and spec data above- this pairing gives GPT-5.6 Terra no edge on price, context, cache discount, or measured performance — pick it only for qualitative fit (ecosystem, compliance, model behavior on your prompts)
- cost dominates: $0.450/Mtok blended vs $4.50 — 90% less on the same 50/50 token mix
- raw capability matters more than price: 90.7 vs 87.7 average benchmark score
Price movement
recorded changes since we began tracking each model · last checked Aug 28, 2026| Model | Changes | Latest move | Old → new $/M |
|---|---|---|---|
| GPT-5.6 Terra | 1 | price cut on Aug 1, 2026 | $2.5/$15 → $2/$12/Mtok |
| GPT-5.6 Luna | 1 | price cut on Aug 1, 2026 | $1/$6 → $0.2/$1.2/Mtok |
The cheaper option here — GPT-5.6 Luna costs $0.450/Mtok blended on OpenAI.
Summary
GPT-5.6 Terra by OpenAI costs $2.00/Mtok input and $12.00/Mtok output, with a 1M-token context window. It supports text, image input.
GPT-5.6 Luna by OpenAI costs $0.200/Mtok input and $1.20/Mtok output, with a 1M-token context window. It supports text, image input.
On a blended cost basis, GPT-5.6 Luna is 90% cheaper than GPT-5.6 Terra.
On benchmarks, GPT-5.6 Luna scores higher (90.7 vs 87.7) on average. In terms of value, GPT-5.6 Luna has better performance per dollar (201.6 vs 19.5).
Note: Pricing is per million tokens. Actual costs vary with usage patterns, prompt caching, and batch discounts. Always verify against official provider pricing pages.