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A · closed · GPT-5.x

GPT-5.4

OpenAI

B · closed · GPT-5.x

GPT-5.6 Sol

OpenAI

1:13

overall capability wins (2 ties across 16 scored). GPT-5.6 Sol leads overall.

  • Reasoning1:6
  • Coding0:5
  • Arena0:1
  • Tool use0:1
  • Pricing3:0
  • Speed1:1

Verdict

GPT-5.6 Sol leads coding (widest gap: +230.6 on WebDev Elo); GPT-5.6 Sol ranks higher on LMArena (+18 Elo); GPT-5.4 is ~1.4x cheaper on a blended token basis than GPT-5.6 Sol.

  • GPT-5.6 Sol leads coding (widest gap: +230.6 on WebDev Elo)
  • GPT-5.6 Sol ranks higher on LMArena (+18 Elo)
  • GPT-5.4 is ~1.4x 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-5.4
$6.25
GPT-5.6 Sol
$9

GPT-5.4 is about 1.4x 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

Mar 5, 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

$2.50

$4

A +$1.50

Output $/1M

$15

$20

A +$5

Blended $/1M (3∶1)

$5.63

$8

A +$2.38

Speed

tok/s

85

96

B +11

TTFT (s)

0.4

0.45

A +0.05

Reasoning

MMLU-Pro

—

—

—

GPQA Diamond

92.0

94.1

B +2.1 pts

Humanity's Last Exam

43.7

49.5

B +5.8 pts

AIME 2025

—

—

—

MATH-500

—

—

—

Humanity's Last Exam (with tools)

—

—

—

AA-Omniscience Accuracy

50.8

59.4

B +8.6 pts

AA-LCR v1.1

82.0

84.0

B +2.0 pts

CritPt

23.4

32.3

B +8.9 pts

MMMU-Pro

78.4

83.4

B +5.0 pts

IFBench

73.9

72.7

A +1.2 pts

Chartography

—

—

—

Chartography (With Tools)

—

—

—

Coding

SWE-bench Verified

—

—

—

SWE-bench Pro

57.7

64.6

B +6.9 pts

SWE-bench Multilingual

—

—

—

LiveCodeBench

—

—

—

Terminal-Bench 2.1

78.3

88.0

B +9.7 pts

Aider Polyglot

—

—

—

Terminal-Bench 3

—

34.6

—

BigCodeBench

—

—

—

SciCode

56.6

57.1

B +0.5 pts

CursorBench

—

67.2

—

SWE-Rebench

57.6

62.3

B +4.7 pts

NL2Repo-Bench

—

—

—

DeepSWE

—

72.7

—

WebDev Arena

1,387

1,617

B +231 Elo

Terminal-Bench 4.0

—

37.3

—

CursorBench 4.0

—

—

—

FrontierCode v1.1 (Main)

—

—

—

Arena

LMArena Elo

1,466

1,484

B +18 Elo

GPT-5.4

Context
1.1M / 128K out
Parameters
—
Price
$2.50 / $15
Speed
85 tok/s · 0.4s TTFT
Modalities
text, image → text
License
Proprietary

Solid mid-2026 OpenAI workhorse between GPT-5 and the 5.5/5.6 flagships.

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.

Reasoning & knowledge

GPQA: B +2.1HLE: B +5.8CritPt: B +8.9AA-LCR: B +2.0Omniscience Acc.: B +8.6MMMU-Pro: B +5.0IFBench: A +1.2

Coding

SWE-Pro: B +6.9TermBench: B +9.7SciCode: B +0.5SWE-Rebench: B +4.7WebDev Elo: B +231

Tool use & function calling

τ³-Banking: B +4.7

Arena

Arena Elo: B +18

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