vs
0:2
overall capability wins (2 ties across 4 scored). GPT-5.6 Sol leads overall.
- Reasoning0:2
- Pricing0:3
- Speed0:2
Verdict
GPT-5.6 Sol edges reasoning & knowledge; GPT-5.6 Sol is ~8.4x cheaper on a blended token basis than GPT-5.5 Pro.
- GPT-5.6 Sol edges reasoning & knowledge
- GPT-5.6 Sol is ~8.4x cheaper on a blended token basis than GPT-5.5 Pro
Cost for 1M in + 250K out
Illustrative chat workload at primary-provider list prices.
- GPT-5.5 Pro
- $75
- GPT-5.6 Sol
- $9
GPT-5.6 Sol is about 8.3x 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
Apr 23, 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
$30
$4
Output $/1M
$180
$20
Blended $/1M (3∶1)
$67.50
$8
Speed
tok/s
68
96
TTFT (s)
0.8
0.45
Reasoning
MMLU-Pro
—
—
GPQA Diamond
—
94.1
Humanity's Last Exam
43.1
49.5
AIME 2025
—
—
MATH-500
—
—
Humanity's Last Exam (with tools)
—
—
AA-Omniscience Accuracy
—
59.4
AA-LCR v1.1
—
84.0
CritPt
30.6
32.3
MMMU-Pro
—
83.4
IFBench
—
72.7
Chartography
—
—
Chartography (With Tools)
—
—
Coding
SWE-bench Verified
—
—
SWE-bench Pro
—
64.6
SWE-bench Multilingual
—
—
LiveCodeBench
—
—
Terminal-Bench 2.1
—
88.0
Aider Polyglot
—
—
Terminal-Bench 3
—
34.6
BigCodeBench
—
—
SciCode
—
57.1
CursorBench
—
67.2
SWE-Rebench
—
62.3
NL2Repo-Bench
—
—
DeepSWE
—
72.7
WebDev Arena
—
1,617
Terminal-Bench 4.0
—
37.3
CursorBench 4.0
—
—
FrontierCode v1.1 (Main)
—
—
Arena
LMArena Elo
—
1,484
| Metric | GPT-5.5 Pro | GPT-5.6 Sol | Delta |
|---|---|---|---|
| Identity | |||
| Organization | OpenAI | OpenAI | — |
| Family | GPT-5.x | GPT-5.x | — |
| License | Proprietary | Proprietary | — |
| Open weights | No | No | — |
| Release | Apr 23, 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 | $30 | $4 | B +$26 |
| Output $/1M | $180 | $20 | B +$160 |
| Blended $/1M (3∶1) | $67.50 | $8 | B +$59.50 |
| Speed | |||
| tok/s | 68 | 96 | B +28 |
| TTFT (s) | 0.8 | 0.45 | B +0.35 |
| Reasoning | |||
| MMLU-Pro | — | — | — |
| GPQA Diamond | — | 94.1 | — |
| Humanity's Last Exam | 43.1 | 49.5 | B +6.4 pts |
| AIME 2025 | — | — | — |
| MATH-500 | — | — | — |
| Humanity's Last Exam (with tools) | — | — | — |
| AA-Omniscience Accuracy | — | 59.4 | — |
| AA-LCR v1.1 | — | 84.0 | — |
| CritPt | 30.6 | 32.3 | B +1.7 pts |
| MMMU-Pro | — | 83.4 | — |
| IFBench | — | 72.7 | — |
| Chartography | — | — | — |
| Chartography (With Tools) | — | — | — |
| Coding | |||
| SWE-bench Verified | — | — | — |
| SWE-bench Pro | — | 64.6 | — |
| SWE-bench Multilingual | — | — | — |
| LiveCodeBench | — | — | — |
| Terminal-Bench 2.1 | — | 88.0 | — |
| Aider Polyglot | — | — | — |
| Terminal-Bench 3 | — | 34.6 | — |
| BigCodeBench | — | — | — |
| SciCode | — | 57.1 | — |
| CursorBench | — | 67.2 | — |
| SWE-Rebench | — | 62.3 | — |
| NL2Repo-Bench | — | — | — |
| DeepSWE | — | 72.7 | — |
| WebDev Arena | — | 1,617 | — |
| Terminal-Bench 4.0 | — | 37.3 | — |
| CursorBench 4.0 | — | — | — |
| FrontierCode v1.1 (Main) | — | — | — |
| Arena | |||
| LMArena Elo | — | 1,484 | — |
GPT-5.5 Pro
- Context
- 1.1M / 128K out
- Parameters
- —
- Price
- $30 / $180
- Speed
- 68 tok/s · 0.8s TTFT
- Modalities
- text, image → text
- License
- Proprietary
Premium compute tier for GPT-5.5 with elevated reasoning budgets; priced for highest-complexity workloads.
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.