Why is this comparison indexable?

It has 6 verifiable comparison points, and both models have pricing or benchmark data.

Are missing metrics invented?

No. Metrics without LMSpeed data are omitted from this report.

Back to models

Data points: 175

Model compare

GPT-5.4 vs GPT-5.5

The readout for GPT-5.4 and GPT-5.5, before the detailed comparison sheet.

Model A

GPT-5.4

OpenAI

Contender

Model B

GPT-5.5

OpenAI

Leading

Key Takeaways

Weighted outcome: GPT-5.5. Benchmark capability categories carry 80%, while price, API performance, and availability carry 20%.

Decision read

GPT-5.5

GPT-5.5 has the higher weighted result; Model A / B score 48.6 to 51.4.

Evidence depth

175 data points

Includes 55 benchmark rows, 0 audit samples, and 10 provider examples.

Selection signal

Start with GPT-5.5

The charts below split 65 high-signal samples across speed, scores, and audit health.

Change comparison

Switch either side of this report to compare another model with the same LMSpeed data pipeline.

Model AModel B

Comparison sheet

This report only uses LMSpeed data for GPT-5.4 and GPT-5.5: pricing, speed aggregates, third-party benchmark scores, and shared provider samples.

Model compare	GPT-5.4	GPT-5.5
Overall leader	Contender	Leading
Weighted overall score	48.6 pts	51.4 pts
Benchmark category leads	2 categories	4 categories
Operational advantages	Cheapest input price, Average speed, First-token latency, Free providers, Provider coverage	No data
Context window	1.1M tokens	1.1M tokens
Max output	128K tokens	128K tokens
Modalities	Input TextImageFile Output Text	Input FileImageText Output Text
Features	Text inputImage inputFile inputText outputTool callingStructured outputsJSON modeReasoning	Text inputImage inputFile inputText outputTool callingStructured outputsJSON modeReasoning

The overall result weights benchmark capability categories at 80% and price, API speed/latency, and availability at 20%. Recent test volume does not affect the winner, and missing benchmark categories are excluded.

Model metadata

Model compare	GPT-5.4	GPT-5.5
Developer	OpenAI	OpenAI
Released	Mar 2026	Apr 2026
Parameters	No data	No data
Tokenizer	GPT	GPT
Knowledge cutoff	No data	2025-12-01
OpenRouter ID	openai/gpt-5.4	openai/gpt-5.5
References	No data	No data

When to choose each model

This report only uses LMSpeed data for GPT-5.4 and GPT-5.5: pricing, speed aggregates, third-party benchmark scores, and shared provider samples.

GPT-5.4

GPT-5.4 is stronger in benchmark categories (Coding, Math) and operational dimensions (Cheapest input price, Average speed, First-token latency, Free providers, Provider coverage).

GPT-5.5

GPT-5.5 leads these benchmark categories: Agents, Reasoning, Multimodal, Instruction following.

Benchmark score comparison

Third-party benchmark profile synced into LMSpeed; only metrics available for both models are shown.

Category performance

Compare benchmark category scores on a 0-100 scale. Select a category to inspect the gap.

Model A coverage: 7 / 8
Model B coverage: 7 / 8
Shared: 7 shared categories

Avg. score

GPT-5.4

56.6

Avg. score

GPT-5.5

57.7

Agents

GPT-5.5 leads by 4.6

GPT-5.456.3

GPT-5.560.9

Coding

GPT-5.4 leads by 2.9

GPT-5.462.2

GPT-5.559.3

Reasoning

GPT-5.5 leads by 3.1

GPT-5.455.7

GPT-5.558.8

Knowledge

Tied

GPT-5.458.5

GPT-5.558.5

Math

GPT-5.4 leads by 0.6

GPT-5.456.8

GPT-5.556.2

Multilingual

No data

GPT-5.4-

GPT-5.5-

Multimodal

GPT-5.5 leads by 3.2

GPT-5.452.5

GPT-5.555.7

Instruction following

GPT-5.5 leads by 0.8

GPT-5.454

GPT-5.554.8

Professional benchmark details

Metric-level scores with benchmark source, rank depth, confidence, error, and evaluation date where available.

Group

Aggregatereported

Provider	GPT-5.4	GPT-5.5
6345ywz API50 tests	GPT-5.4 speed / latency 41 tok/s / 6581ms input / output No data	GPT-5.5 speed / latency 38 tok/s / 8937ms input / output No data
天宫造物50 tests	GPT-5.4 speed / latency 50 tok/s / 7305ms input / output No data	GPT-5.5 speed / latency N/A / N/A input / output No data
Tokeness.io30 tests	GPT-5.4 speed / latency 53 tok/s / 1112ms input / output No data	GPT-5.5 speed / latency 52 tok/s / 3050ms input / output No data
FreeModel25 tests	GPT-5.4 speed / latency N/A / N/A input / output No data	GPT-5.5 speed / latency 38 tok/s / 7849ms input / output No data
KJK API25 tests	GPT-5.4 speed / latency 58 tok/s / 4453ms input / output No data	GPT-5.5 speed / latency N/A / N/A input / output No data
180txt API	GPT-5.4 gpt-5.4-2026-03-05 speed / latency No data input / output $0/M/$0/M	GPT-5.5 gpt-5.5-openai-compact speed / latency No data input / output $0.750/M/$4.50/M
DeadlySignal API	GPT-5.4 gpt-5.4 speed / latency No data input / output $0/M/$0/M	GPT-5.5 gpt-5.5 speed / latency No data input / output $0/M/$0/M
兔子API	GPT-5.4 gpt-5.4-openai-compact speed / latency No data input / output $0/request	GPT-5.5 gpt-5.5-xhigh speed / latency No data input / output $0/request
鲨鱼魔法	GPT-5.4 [mt]q\|次/gpt-5.4 speed / latency No data input / output $13.50/request	GPT-5.5 [lq]t\|YQ/gpt-5.5 speed / latency No data input / output $0/M/$0/M
熊猫 API	GPT-5.4 熊猫-按量-gpt-5.4 speed / latency No data input / output $0.0054/M/$0.043/M	GPT-5.5 熊猫-按量-gpt-5.5 speed / latency No data input / output $0.0089/M/$0.072/M

Comparison sheet

Model metadata

When to choose each model

Benchmark score comparison

Category performance

Agents

Coding

Reasoning

Knowledge

Math

Multilingual

Multimodal

Instruction following

Professional benchmark details

BenchLM overall score

Input price

Blended price

Output price

AA-LCR

ARC-AGI-2

ARC-AGI-3

GPQA

CritPt

HLE

BenchLM Reasoning score

React Native Evals

Vibe Code Bench

EEBench

AA-SciCode

AA Coding Index

SWE-bench Pro

BenchLM Coding score

FrontierMath v2 (Tiers 1-3)

FrontierMath v2 (Tier 4)

BenchLM Math score

GPQA-D

AA-Omniscience Accuracy

AA-GPQA Diamond

HLE w/o tools

AA-HLE

AA-Omniscience Hallucination Rate

AA-Omniscience Index

BenchLM Knowledge score

Artificial Analysis Intelligence Index

MMMU-Pro w/ Python

MMMU-Pro

OfficeQA Pro

AA-MMMU-Pro

BenchLM Multimodal Grounded score

Design Arena Website

BenchLM Instruction Following score

AA-IFBench

Gert Labs

τ²-bench results

CyberGym

APEX-Agents-AA

ExploitGym

Toolathlon

JobBench

ApprenticeBench

Terminal-Bench 2.0

OSWorld-Verified

BrowseComp

ResearchClawBench

MCP Atlas

AA Agentic Index

BenchLM Agentic score

GDPval-AA

GDPval-AA

API audit comparison

Provider examples

FAQ

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