vs
0:19
overall capability wins (2 ties across 21 scored). GPT-5.6 Sol leads overall.
- Reasoning0:6
- Coding0:9
- Arena0:1
- Agents0:2
- Tool use0:1
- Composite indices0:2
- Pricing3:0
- Speed2:0
Verdict
GPT-5.6 Sol leads coding (widest gap: +98.4 on WebDev Elo); GPT-5.6 Sol ranks higher on LMArena (+31 Elo); GPT-5.6 Luna is ~17.8x cheaper on a blended token basis than GPT-5.6 Sol.
- GPT-5.6 Sol leads coding (widest gap: +98.4 on WebDev Elo)
- GPT-5.6 Sol ranks higher on LMArena (+31 Elo)
- GPT-5.6 Luna is ~17.8x cheaper on a blended token basis than GPT-5.6 Sol
Cost for 1M in + 250K out
Illustrative chat workload at primary-provider list prices.
- GPT-5.6 Luna
- $0.50
- GPT-5.6 Sol
- $9
GPT-5.6 Luna is about 18.0x 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
Jul 9, 2026
Jul 9, 2026
Knowledge cutoff
-
2026-02-16
API / provider
OpenAI
OpenAI
Modalities
text, image → text
text, image → text
Specs
Context window
1.1M
1.1M
Max output
128K
128K
Parameters
—
—
Pricing
Input $/1M
$0.20
$4
Output $/1M
$1.20
$20
Blended $/1M (3∶1)
$0.45
$8
Speed
tok/s
195
96
TTFT (s)
0.2
0.45
Reasoning
MMLU-Pro
—
—
GPQA Diamond
91.1
94.1
Humanity's Last Exam
39.5
49.5
AIME 2025
—
—
MATH-500
—
—
Humanity's Last Exam (with tools)
—
—
AA-Omniscience Accuracy
42.7
59.4
AA-LCR v1.1
83.7
84.0
CritPt
20.6
32.3
MMMU-Pro
78.6
83.4
IFBench
—
72.7
Chartography
—
—
Chartography (With Tools)
—
—
Coding
SWE-bench Verified
—
—
SWE-bench Pro
62.7
64.6
SWE-bench Multilingual
—
—
LiveCodeBench
—
—
Terminal-Bench 2.1
80.9
88.0
Aider Polyglot
—
—
Terminal-Bench 3
14.3
34.6
BigCodeBench
—
—
SciCode
53.6
57.1
CursorBench
61.1
67.2
SWE-Rebench
43.6
62.3
NL2Repo-Bench
—
—
DeepSWE
67.0
72.7
WebDev Arena
1,519
1,617
Terminal-Bench 4.0
17.3
37.3
CursorBench 4.0
—
—
FrontierCode v1.1 (Main)
—
—
Arena
LMArena Elo
1,453
1,484
| Metric | GPT-5.6 Luna | GPT-5.6 Sol | Delta |
|---|---|---|---|
| Identity | |||
| Organization | OpenAI | OpenAI | — |
| Family | GPT-5.x | GPT-5.x | — |
| License | Proprietary | Proprietary | — |
| Open weights | No | No | — |
| Release | Jul 9, 2026 | Jul 9, 2026 | — |
| Knowledge cutoff | - | 2026-02-16 | — |
| API / provider | OpenAI | OpenAI | — |
| Modalities | text, image → text | text, image → text | — |
| Specs | |||
| Context window | 1.1M | 1.1M | tie |
| Max output | 128K | 128K | tie |
| Parameters | — | — | — |
| Pricing | |||
| Input $/1M | $0.20 | $4 | A +$3.80 |
| Output $/1M | $1.20 | $20 | A +$18.80 |
| Blended $/1M (3∶1) | $0.45 | $8 | A +$7.55 |
| Speed | |||
| tok/s | 195 | 96 | A +99 |
| TTFT (s) | 0.2 | 0.45 | A +0.25 |
| Reasoning | |||
| MMLU-Pro | — | — | — |
| GPQA Diamond | 91.1 | 94.1 | B +3.0 pts |
| Humanity's Last Exam | 39.5 | 49.5 | B +10.0 pts |
| AIME 2025 | — | — | — |
| MATH-500 | — | — | — |
| Humanity's Last Exam (with tools) | — | — | — |
| AA-Omniscience Accuracy | 42.7 | 59.4 | B +16.7 pts |
| AA-LCR v1.1 | 83.7 | 84.0 | B +0.3 pts |
| CritPt | 20.6 | 32.3 | B +11.7 pts |
| MMMU-Pro | 78.6 | 83.4 | B +4.8 pts |
| IFBench | — | 72.7 | — |
| Chartography | — | — | — |
| Chartography (With Tools) | — | — | — |
| Coding | |||
| SWE-bench Verified | — | — | — |
| SWE-bench Pro | 62.7 | 64.6 | B +1.9 pts |
| SWE-bench Multilingual | — | — | — |
| LiveCodeBench | — | — | — |
| Terminal-Bench 2.1 | 80.9 | 88.0 | B +7.1 pts |
| Aider Polyglot | — | — | — |
| Terminal-Bench 3 | 14.3 | 34.6 | B +20.3 pts |
| BigCodeBench | — | — | — |
| SciCode | 53.6 | 57.1 | B +3.5 pts |
| CursorBench | 61.1 | 67.2 | B +6.1 pts |
| SWE-Rebench | 43.6 | 62.3 | B +18.7 pts |
| NL2Repo-Bench | — | — | — |
| DeepSWE | 67.0 | 72.7 | B +5.7 pts |
| WebDev Arena | 1,519 | 1,617 | B +98 Elo |
| Terminal-Bench 4.0 | 17.3 | 37.3 | B +20.0 pts |
| CursorBench 4.0 | — | — | — |
| FrontierCode v1.1 (Main) | — | — | — |
| Arena | |||
| LMArena Elo | 1,453 | 1,484 | B +31 Elo |
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.
GPT-5.6 Sol
- Context
- 1.1M / 128K out
- Parameters
- —
- Price
- $4 / $20
- Speed
- 96 tok/s · 0.45s TTFT
- Modalities
- text, image → text
- License
- Proprietary
OpenAI's July 2026 flagship reasoning tier, tuned for hard STEM and agentic work; ChatGPT's top API SKU in the 5.6 family. Promotional Standard rates are $4/$20 (through at least Nov 21, 2026). Fast mode (2× price) delivers up to 2.5× Standard speed, and the Cerebras-powered Ultrafast preview reaches up to 750 tok/s.
Benchmark charts
Winner bars are emphasized. Per-benchmark deltas sit above each chart.