vs
0:12
overall capability wins (1 ties across 13 scored). GPT-5.6 Luna leads overall.
- Reasoning0:6
- Coding0:3
- Arena0:1
- Tool use0:1
- Pricing0:3
- Speed0:2
- Specs0:1
Verdict
GPT-5.6 Luna leads coding (widest gap: +45.7 on TermBench); GPT-5.6 Luna ranks higher on LMArena (+18 Elo); GPT-5.6 Luna offers ~2.6x larger context (1.1M vs 400K).
- GPT-5.6 Luna leads coding (widest gap: +45.7 on TermBench)
- GPT-5.6 Luna ranks higher on LMArena (+18 Elo)
- GPT-5.6 Luna offers ~2.6x larger context (1.1M vs 400K)
- GPT-5.6 Luna is ~7.6x cheaper on a blended token basis than GPT-5
Cost for 1M in + 250K out
Illustrative chat workload at primary-provider list prices.
- GPT-5
- $3.75
- GPT-5.6 Luna
- $0.50
GPT-5.6 Luna is about 7.5x cheaper on this workload.
Price per 1M tokens
Full comparison
Organization
OpenAI
OpenAI
Family
GPT-5.x
GPT-5.x
License
Proprietary
Proprietary
Open weights
No
No
Release
Aug 7, 2025
Jul 9, 2026
Knowledge cutoff
2024-09
-
API / provider
OpenAI
OpenAI
Modalities
text, image → text
text, image → text
Specs
Context window
400K
1.1M
Max output
128K
128K
Parameters
—
—
Pricing
Input $/1M
$1.25
$0.20
Output $/1M
$10
$1.20
Blended $/1M (3∶1)
$3.44
$0.45
Speed
tok/s
90
195
TTFT (s)
0.4
0.2
Reasoning
MMLU-Pro
—
—
GPQA Diamond
85.4
91.1
Humanity's Last Exam
28.5
39.5
AIME 2025
94.6
—
MATH-500
—
—
Humanity's Last Exam (with tools)
—
—
AA-Omniscience Accuracy
40.3
42.7
AA-LCR v1.1
78.2
83.7
CritPt
5.7
20.6
MMMU-Pro
74.2
78.6
IFBench
73.1
—
Chartography
—
—
Chartography (With Tools)
—
—
Coding
SWE-bench Verified
74.9
—
SWE-bench Pro
41.8
62.7
SWE-bench Multilingual
—
—
LiveCodeBench
—
—
Terminal-Bench 2.1
35.2
80.9
Aider Polyglot
88.0
—
Terminal-Bench 3
—
14.3
BigCodeBench
—
—
SciCode
42.9
53.6
CursorBench
—
61.1
SWE-Rebench
—
43.6
NL2Repo-Bench
—
—
DeepSWE
—
67.0
WebDev Arena
—
1,519
Terminal-Bench 4.0
—
17.3
CursorBench 4.0
—
—
FrontierCode v1.1 (Main)
—
—
Arena
LMArena Elo
1,435
1,453
| Metric | GPT-5 | GPT-5.6 Luna | Delta |
|---|---|---|---|
| Identity | |||
| Organization | OpenAI | OpenAI | — |
| Family | GPT-5.x | GPT-5.x | — |
| License | Proprietary | Proprietary | — |
| Open weights | No | No | — |
| Release | Aug 7, 2025 | Jul 9, 2026 | — |
| Knowledge cutoff | 2024-09 | - | — |
| API / provider | OpenAI | OpenAI | — |
| Modalities | text, image → text | text, image → text | — |
| Specs | |||
| Context window | 400K | 1.1M | B +650K |
| Max output | 128K | 128K | tie |
| Parameters | — | — | — |
| Pricing | |||
| Input $/1M | $1.25 | $0.20 | B +$1.05 |
| Output $/1M | $10 | $1.20 | B +$8.80 |
| Blended $/1M (3∶1) | $3.44 | $0.45 | B +$2.99 |
| Speed | |||
| tok/s | 90 | 195 | B +105 |
| TTFT (s) | 0.4 | 0.2 | B +0.20 |
| Reasoning | |||
| MMLU-Pro | — | — | — |
| GPQA Diamond | 85.4 | 91.1 | B +5.7 pts |
| Humanity's Last Exam | 28.5 | 39.5 | B +11.0 pts |
| AIME 2025 | 94.6 | — | — |
| MATH-500 | — | — | — |
| Humanity's Last Exam (with tools) | — | — | — |
| AA-Omniscience Accuracy | 40.3 | 42.7 | B +2.4 pts |
| AA-LCR v1.1 | 78.2 | 83.7 | B +5.5 pts |
| CritPt | 5.7 | 20.6 | B +14.9 pts |
| MMMU-Pro | 74.2 | 78.6 | B +4.4 pts |
| IFBench | 73.1 | — | — |
| Chartography | — | — | — |
| Chartography (With Tools) | — | — | — |
| Coding | |||
| SWE-bench Verified | 74.9 | — | — |
| SWE-bench Pro | 41.8 | 62.7 | B +20.9 pts |
| SWE-bench Multilingual | — | — | — |
| LiveCodeBench | — | — | — |
| Terminal-Bench 2.1 | 35.2 | 80.9 | B +45.7 pts |
| Aider Polyglot | 88.0 | — | — |
| Terminal-Bench 3 | — | 14.3 | — |
| BigCodeBench | — | — | — |
| SciCode | 42.9 | 53.6 | B +10.7 pts |
| CursorBench | — | 61.1 | — |
| SWE-Rebench | — | 43.6 | — |
| NL2Repo-Bench | — | — | — |
| DeepSWE | — | 67.0 | — |
| WebDev Arena | — | 1,519 | — |
| Terminal-Bench 4.0 | — | 17.3 | — |
| CursorBench 4.0 | — | — | — |
| FrontierCode v1.1 (Main) | — | — | — |
| Arena | |||
| LMArena Elo | 1,435 | 1,453 | B +18 Elo |
GPT-5
- Context
- 400K / 128K out
- Parameters
- —
- Price
- $1.25 / $10
- Speed
- 90 tok/s · 0.4s TTFT
- Modalities
- text, image → text
- License
- Proprietary
Original GPT-5 GA release - still a strong price/performance option versus newer premium SKUs.
GPT-5.6 Luna
- Context
- 1.1M / 128K out
- Parameters
- —
- Price
- $0.20 / $1.20
- Speed
- 195 tok/s · 0.2s TTFT
- Modalities
- text, image → text
- License
- Proprietary
Fastest, cheapest GPT-5.6 tier for high-volume chat, classification, and light coding; July 30, 2026 API cut dropped Standard rates 80% to $0.20/$1.20.
Benchmark charts
Winner bars are emphasized. Per-benchmark deltas sit above each chart.