Model comparison

GPT-5.5 vs Laguna S 2.1

Data verified July 21, 2026

Head-to-head evidence from 3 shared benchmark results across 2 categories. Overall scores shown here use the public BenchAlign v5 ranking lane.

GPT-5.5

OpenAI

73.51/100

No comparison

Laguna S 2.1

Poolside

N/A

1 category wins1 category wins

Public leaderboard positions: GPT-5.5 #9 (Estimated); Laguna S 2.1 unranked (Not scored). Intervals and evidence labels describe ranking uncertainty, not a guarantee for a specific workload.

Evidence parity. GPT-5.5 and Laguna S 2.1 share 3 comparable benchmark results. 2 of 8 categories are comparable. 54 results are unique to GPT-5.5; 3 to Laguna S 2.1.

Updated July 21, 2026

Shared results: 3
GPT-5.5 only: 54
Laguna S 2.1 only: 3
Comparable categories: 2 / 8

Treat this as a split decision. GPT-5.5 makes more sense if agentic is the priority; Laguna S 2.1 is the better fit if coding is the priority or you want the cheaper token bill.

Confidence note. This is a partial-evidence comparison with 3 shared benchmark results across 2 evidence categories; 2 of 8 categories currently have scoreable aggregates for both models. Treat the verdict as directional until coverage is more balanced.

Why this result

GPT-5.5 and Laguna S 2.1 finish on the same BenchAlign overall score, so this is less about a single winner and more about where the edge shows up. The BenchAlign headline says tie; the benchmark table is where the real choice happens.

GPT-5.5 is also the more expensive model on tokens at $5.00 input / $30.00 output per 1M tokens, versus $0.10 input / $0.20 output per 1M tokens for Laguna S 2.1. That is roughly 150.0x on output cost alone.

Category breakdown

Exact category averages are shown below. Not measured means BenchLM does not have enough sourced public coverage for that model and category.

Category scores and score margins for GPT-5.5 and Laguna S 2.1
Category	GPT-5.5	Δ	Laguna S 2.1
Agentic	GPT-5.581.6	Margin← 11.4	Laguna S 2.170.2
Coding	GPT-5.558.6	Margin→ 0.8	Laguna S 2.159.4
Reasoning	GPT-5.585.0	MarginNo overlap	Laguna S 2.1Not measured
Knowledge	GPT-5.557.8	MarginNo overlap	Laguna S 2.1Not measured
Math	GPT-5.547.6	MarginNo overlap	Laguna S 2.1Not measured
Multimodal	GPT-5.570.4	MarginNo overlap	Laguna S 2.1Not measured

Decisive benchmark drivers

The largest measured benchmark gaps in this matchup, with exact reported values.

A · GPT-5.5B · Laguna S 2.1

Terminal-Bench 2.0
Agentic
Source ↗
A 82%B 70.2%
Winner: GPT-5.5Δ 11.8
Terminal-Bench 2.0: GPT-5.5 scored 82%; Laguna S 2.1 scored 70.2%. GPT-5.5 wins this benchmark.
SWE-bench Pro
Coding
Source ↗
A 58.6%B 59.4%
Winner: Laguna S 2.1Δ 0.8
SWE-bench Pro: GPT-5.5 scored 58.6%; Laguna S 2.1 scored 59.4%. Laguna S 2.1 wins this benchmark.

Operational comparison

Runtime and commercial metrics are compared only when both models have a complete sourced value.

Metric	GPT-5.5	Laguna S 2.1	Comparison
Input / output priceUSD per 1M tokens	GPT-5.5$5 input / $30 output	Laguna S 2.1$0.1 input / $0.2 output	Laguna S 2.1 has the lower combined listed price.
Generation speedtokens per second	GPT-5.5Not available	Laguna S 2.1Not available	A complete speed comparison is not available.
First-answer latencyseconds to first token	GPT-5.5Not available	Laguna S 2.1Not available	A complete latency comparison is not available.
Context windowmaximum listed tokens	GPT-5.51M	Laguna S 2.11M	Listed context windows are equal.

Benchmark Deep Dive

AgenticGPT-5.5 wins

25 benchmarks

Benchmark	GPT-5.5	Laguna S 2.1	Result
Terminal-Bench 2.0Source	82%	70.2%	GPT-5.5 leads
CyberGymSource	81.8%	—	Not comparable
BrowseCompSource	84.4%	—	Not comparable
OSWorld-VerifiedSource	78.7%	—	Not comparable
MCP AtlasSource	75.3%	—	Not comparable
ToolathlonSource	55.6%	—	Not comparable
τ²-bench resultsSource	93.9%	—	Not comparable
AA Agentic IndexSource	44.9%	—	Not comparable
APEX-Agents-AASource	37.7%	—	Not comparable
GDPval-AASource	49.5%	—	Not comparable
GDPval-AASource	1490	—	Not comparable
Gert LabsSource	72.93%	—	Not comparable
ResearchClawBenchSource	17.0%	—	Not comparable
OSWorld 2.0Source	13.0%	—	Not comparable
JobBenchSource	42.7%	—	Not comparable
ExploitGymSource	13.4%	—	Not comparable
AA BriefcaseSource	1154	—	Not comparable
AA AutomationBenchSource	42.1%	—	Not comparable
AA EnterpriseOps-GymSource	46.6%	—	Not comparable
AA Harvey LABSource	86.3%	—	Not comparable
AA ITBenchSource	45.8%	—	Not comparable
AA Tau3 BankingSource	31.3%	—	Not comparable
terminalBenchHardSource	60.6%	—	Not comparable
aaTerminalBench21Source	84.3%	—	Not comparable
Toolathlon-VerifiedSource	—	49.7%	Not comparable

CodingLaguna S 2.1 wins

11 benchmarks

Benchmark	GPT-5.5	Laguna S 2.1	Result
SWE-bench ProSource	58.6%	59.4%	Laguna S 2.1 leads
Terminal-Bench 2.0Source	82.0%	70.2%	GPT-5.5 leads
Vibe Code BenchSource	69.85%	—	Not comparable
React Native EvalsSource	84.7%	—	Not comparable
cursorBench31Source	59.2%	—	Not comparable
cursorBench32Source	58.4%	—	Not comparable
AA Coding IndexSource	74.9%	—	Not comparable
AA-SciCodeSource	56.1%	—	Not comparable
FrontierCode 1.1 MainSource	43.0%	—	Not comparable
SWE MultilingualSource	—	78.5%	Not comparable
deepSweSource	—	40.4%	Not comparable

Reasoning

5 benchmarks

Benchmark	GPT-5.5	Laguna S 2.1	Result
MRCR v2 64K-128KSource	83.1%	—	Not comparable
MRCR v2 128K-256KSource	87.5%	—	Not comparable
ARC-AGI-2Source	85%	—	Not comparable
AA-LCRSource	74.3%	—	Not comparable
CritPtSource	27.1%	—	Not comparable

Knowledge

10 benchmarks

Benchmark	GPT-5.5	Laguna S 2.1	Result
GPQASource	93.6%	—	Not comparable
GPQA-DSource	93.6%	—	Not comparable
HLESource	52.2%	—	Not comparable
HLE w/o toolsSource	41.4%	—	Not comparable
Artificial Analysis Intelligence IndexSource	54.8%	—	Not comparable
AA-GPQA DiamondSource	93.5%	—	Not comparable
AA-HLESource	44.3%	—	Not comparable
AA-Omniscience IndexSource	20.1%	—	Not comparable
AA-Omniscience AccuracySource	56.9%	—	Not comparable
AA-Omniscience Hallucination RateSource	85.5%	—	Not comparable

Math

3 benchmarks

Benchmark	GPT-5.5	Laguna S 2.1	Result
FrontierMath (legacy)Source	51.7%	—	Not comparable
FrontierMath v2 (Tiers 1-3)Source	51.700%	—	Not comparable
FrontierMath v2 (Tier 4)Source	35.400%	—	Not comparable

Multimodal

5 benchmarks

Benchmark	GPT-5.5	Laguna S 2.1	Result
MMMU-ProSource	81.2%	—	Not comparable
MMMU-Pro w/ PythonSource	83.2%	—	Not comparable
OfficeQA ProSource	54.1%	—	Not comparable
AA-MMMU-ProSource	79.9%	—	Not comparable
Design Arena WebsiteSource	1282	—	Not comparable

Inst. Following

1 benchmarks

Benchmark	GPT-5.5	Laguna S 2.1	Result
AA-IFBenchSource	75.9%	—	Not comparable

Frequently Asked Questions (3)

Which is better, GPT-5.5 or Laguna S 2.1?

GPT-5.5 and Laguna S 2.1 are tied on the BenchAlign overall score, so the right pick depends on which category matters most for your use case.

Which is better for coding, GPT-5.5 or Laguna S 2.1?

Laguna S 2.1 has the edge for coding in this comparison, averaging 59.4 versus 58.6. Inside this category, Terminal-Bench 2.0 is the benchmark that creates the most daylight between them.

Which is better for agentic tasks, GPT-5.5 or Laguna S 2.1?

GPT-5.5 has the edge for agentic tasks in this comparison, averaging 81.6 versus 70.2. Inside this category, Terminal-Bench 2.0 is the benchmark that creates the most daylight between them.

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