LLMcompare

Search

Search for a command to run...

A · closed · GPT-5.x

GPT-5.5

OpenAI

B · closed · GPT-5.x

GPT-5.5 Pro

OpenAI

6:1

overall capability wins (2 ties across 9 scored). Quality is close, so price/speed break the overall tie. GPT-5.5 leads overall.

  • Reasoning1:1
  • Pricing3:0
  • Speed2:0

Verdict

GPT-5.5 is ~6.0x 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
$12.50
GPT-5.5 Pro
$75

GPT-5.5 is about 6.0x 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

Apr 23, 2026

Apr 23, 2026

Knowledge cutoff

-

-

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

$5

$30

A +$25

Output $/1M

$30

$180

A +$150

Blended $/1M (3∶1)

$11.25

$67.50

A +$56.25

Speed

tok/s

70

68

A +2.00

TTFT (s)

0.5

0.8

A +0.30

Reasoning

MMLU-Pro

—

—

—

GPQA Diamond

93.5

—

—

Humanity's Last Exam

45.8

43.1

A +2.7 pts

AIME 2025

—

—

—

MATH-500

—

—

—

Humanity's Last Exam (with tools)

—

—

—

AA-Omniscience Accuracy

58.0

—

—

AA-LCR v1.1

84.3

—

—

CritPt

27.1

30.6

B +3.5 pts

MMMU-Pro

79.9

—

—

IFBench

75.9

—

—

Chartography

—

—

—

Chartography (With Tools)

—

—

—

Coding

SWE-bench Verified

—

—

—

SWE-bench Pro

58.6

—

—

SWE-bench Multilingual

—

—

—

LiveCodeBench

—

—

—

Terminal-Bench 2.1

84.3

—

—

Aider Polyglot

—

—

—

Terminal-Bench 3

—

—

—

BigCodeBench

—

—

—

SciCode

55.8

—

—

CursorBench

58.4

—

—

SWE-Rebench

62.7

—

—

NL2Repo-Bench

—

—

—

DeepSWE

67.0

—

—

WebDev Arena

1,510

—

—

Terminal-Bench 4.0

—

—

—

CursorBench 4.0

—

—

—

FrontierCode v1.1 (Main)

—

—

—

Arena

LMArena Elo

1,476

—

—

GPT-5.5

Context
1.1M / 128K out
Parameters
—
Price
$5 / $30
Speed
70 tok/s · 0.5s TTFT
Modalities
text, image → text
License
Proprietary

Prior OpenAI flagship with strong coding and long context; still widely used alongside the newer 5.6 family.

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.

Benchmark charts

Winner bars are emphasized. Per-benchmark deltas sit above each chart.

Reasoning & knowledge

HLE: A +2.7CritPt: B +3.5

Pick a different pair · Back to catalog