Pairwise benchmark snapshot · Aug 16, 2026

Claude Sonnet 5 vs GPT-5.6 Luna benchmark

Name: Claude Sonnet 5 vs GPT-5.6 Luna AI benchmark comparison
Creator: CompareLLM
License: https://creativecommons.org/licenses/by/4.0/

This page compares Claude Sonnet 5 (Anthropic) and GPT-5.6 Luna (OpenAI) using the latest snapshots we have as of Aug 16, 2026. On preference Elo, Claude Sonnet 5 is ahead by 90 points (1,556 vs 1,466; seed-bootstrap (Aug 16, 2026)). On SWE-bench coding, Claude Sonnet 5 resolves 73.8% versus 61.8% (seed-bootstrap (Aug 16, 2026)). GPT-5.6 Luna streams faster (188 tok/s) while GPT-5.6 Luna is the cheaper output token ($0.6/1M). GPT-5.6 Luna has the larger context window (1.1M tokens). Every cell below is a dated snapshot from a named public source — we do not invent missing scores, and we do not run SWE-bench ourselves.

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Anthropic

Claude Sonnet 5

Anthropic workhorse. Official $2/$10 per 1M tokens made permanent on Aug 10 2026.

Elo 1,556$10/1M out

OpenAI

GPT-5.6 Luna

OpenAI 5.6 fast/cheap tier. Official API $0.20/$1.20 per 1M after the Jul 30 80% Luna cut.

Elo 1,466$0.6/1M out

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Model A

Model B

Quick vs:vs Claude Opus 4.5 vs Claude Opus 4.6 vs Claude Sonnet 4.5 vs Claude 3.7 Sonnet

Interactive Comparison Diagram

Matchup Breakdown

Tug-of-War Matchup Matrix

Category wins across intelligence, speed, and pricing efficiency.

Claude Sonnet 5 (5)vsGPT-5.6 Luna (5)

Claude Sonnet 5: 5W (50%)Overall: Even matchupGPT-5.6 Luna: 5W (50%)

← Claude Sonnet 5GPT-5.6 Luna →

Claude Sonnet 5 (5/5)

Intelligence & Reasoning

Preference Elo, Coding proficiency, SWE-bench & LiveBench accuracy

Preference Elo

1,556vs1,466

Coding Elo

1,562vs1,458

SWE-bench

73.8%vs61.8%

LiveBench

70.4%vs64.2%

GPQA Diamond

82.8%vs75.4%

Claude Sonnet 5: 5WGPT-5.6 Luna: 0W

GPT-5.6 Luna (2/2)

Speed & Latency

Generation throughput and time to first token responsiveness

Output speed

118 tok/svs188 tok/s

Time to first token

175 msvs88 ms

Claude Sonnet 5: 0WGPT-5.6 Luna: 2W

GPT-5.6 Luna (3/3)

Pricing & Capacity

Cost per million tokens and max context window length

Output price

$10/1Mvs$0.6/1M

Input price

$2/1Mvs$0.1/1M

Context window

1Mvs1.1M

Claude Sonnet 5: 0WGPT-5.6 Luna: 3W

Capability Matchup Radar

Multi-Dimensional Capability Radar

Each spoke is a skill. Farther from the center is better (0–100th percentile). Tap any dot to inspect details.

Tap any node to inspect

Percentile 0–100

Dimensional AdvantageEven 3–3

Preference Elo

Claude Sonnet 5

90 pts advantage

Throughput Speed

GPT-5.6 Luna

70 tok/s faster

Price Efficiency

GPT-5.6 Luna

$9.40/1M cheaper

Full Benchmark Score Matrix

—

Elo

High is better

+6%1,556

EloHigh is better

1,466

Code Elo

High is better

+7%1,562

Code EloHigh is better

1,458

LiveBench

High is better

+10%70.4%

LiveBenchHigh is better

64.2%

SWE-bench

High is better

+19%73.8%

SWE-benchHigh is better

61.8%

GPQA

High is better

+10%82.8%

GPQAHigh is better

75.4%

TTFT

Low is better

175 ms

TTFTLow is better

88 ms+99%

Speed

High is better

118 tok/s

SpeedHigh is better

188 tok/s+59%

In $

Low is better

$2/1M

In $Low is better

$0.1/1M+1900%

Out $

Low is better

$10/1M

Out $Low is better

$0.6/1M+1567%

Context

High is better

ContextHigh is better

1.1M+5%

Interactive Simulator

Workload Cost & Savings Calculator

Simulate monthly production API costs based on published $/1M tokens.

Save up to 94% with GPT-5.6 Luna

Monthly Volume50M tokens/mo

Quick Presets:

Token Ratio (In vs Out)70% In / 30% Out

RAG / Search (10% out)Coding / Chat (50% out)

Claude Sonnet 5$220.00 / mo

In: $70.00Out: $150.00

GPT-5.6 Luna$12.50 / mo

In: $3.50Out: $9.00

Estimated Cost Delta

GPT-5.6 Luna is estimated to save $207.50/month ($2,490/year).

Based on 50M tokens (30% gen)

Key Selection Recommendations

1
Claude Sonnet 5:Pick Claude Sonnet 5 when repo-level coding accuracy is the constraint.
2
GPT-5.6 Luna:Pick GPT-5.6 Luna when you are optimizing output cost.
3
GPT-5.6 Luna:Pick GPT-5.6 Luna when time-to-first-token matters more than peak Elo.

Recommended Workload Routing

Repo / coding agentsClaude Sonnet 5

Higher SWE-bench (73.8%).

High-volume chatGPT-5.6 Luna

Lower output list price ($0.6/1M).

Voice / low-latency UIGPT-5.6 Luna

Lower TTFT (88 ms).

Long-document RAGGPT-5.6 Luna

Larger window (1.1M).

Screenshots / visionClaude Sonnet 5

Both accept images. Defaulting to the higher-Elo side (Claude Sonnet 5).

Target Workload	Recommended Pick	Evaluation Rationale
Repo / coding agents	Claude Sonnet 5	Higher SWE-bench (73.8%).
High-volume chat	GPT-5.6 Luna	Lower output list price ($0.6/1M).
Voice / low-latency UI	GPT-5.6 Luna	Lower TTFT (88 ms).
Long-document RAG	GPT-5.6 Luna	Larger window (1.1M).
Screenshots / vision	Claude Sonnet 5	Both accept images. Defaulting to the higher-Elo side (Claude Sonnet 5).

Related Editorial Dispatches & Benchmark Notes

View all news

compareAug 10, 2026

Sonnet vs Opus in 2026: same family, different invoice

Usually Sonnet 5 vs Opus 5. Coding delta versus output $/1M. The workhorse question.

priceAug 10, 2026

Claude Sonnet 5 at $2/$10: the 2026 Anthropic workhorse

Aug 10 2026 made the $2/$10 list permanent. Sonnet is the default Claude unless the repo is actually on fire.

priceJul 30, 2026

GPT-5.6 Luna’s 80% cut: $0.20/$1.20 for volume chat

Luna is the OpenAI fast/cheap 5.6 SKU after Jul 30. It is not Sol. Sort by price and TTFT, not Elo.

launchFeb 18, 2026

Claude Sonnet 4.5 is the previous workhorse — still a valid vs baseline

Most of Opus 4.5 coding at a mid-tier price. Sonnet 5 replaced it as the buy; 4.5 remains a compare baseline.

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LIVE

Anthropic

Claude Sonnet 5

Elo 1,556

LiveBench70.4%

SWE-bench73.8%

Speed118 tok/s

Output cost$10/1M

OpenAI

GPT-5.6 Luna

Elo 1,466

LiveBench64.2%

SWE-bench61.8%

Speed188 tok/s

Output cost$0.6/1M

Frequently Asked Questions

Which is better overall, Claude Sonnet 5 or GPT-5.6 Luna?: Claude Sonnet 5 has the higher preference Elo in our latest snapshot (1,556). “Better” still depends on coding, price, and latency — see the table.
Which is better at coding, Claude Sonnet 5 or GPT-5.6 Luna?: Claude Sonnet 5 leads SWE-bench at 73.8% vs 61.8%. SWE-bench is one harness, not your repo.
Which is cheaper to run in production?: GPT-5.6 Luna output tokens are $0.6/1M versus $10/1M. Input prices and retry rates still move the real bill.
Which is faster, Claude Sonnet 5 or GPT-5.6 Luna?: GPT-5.6 Luna has the lower time-to-first-token (88 ms vs 175 ms). Tokens/sec is a separate column if you care about long completions.
Which has the larger context window?: GPT-5.6 Luna accepts 1.1M tokens versus 1M.
Can I self-host either model?: Neither model is marked open-weights here. You are comparing hosted APIs.
Are these scores from CompareLLM’s own evals?: No. V1 aggregates public leaderboards (and optional first-party latency pings). Each cell names its source and date. Read /methodology.
What does preference Elo mean on this page?: Preference Elo is a crowd vote from LMArena / Arena. People see two hidden answers and pick the one they like more. The model that wins more often gets a higher Elo. That means people preferred it — not that it passed a school test. It is not SWE-bench, not accuracy, and not a number we invent. Claude Sonnet 5 and GPT-5.6 Luna Elo cells are dated snapshots from the named source — we do not compute Arena ourselves.

Similar Head-to-Head Comparisons

All Claude Sonnet 5 matchups →|All GPT-5.6 Luna matchups →

Claude Sonnet 5 vs Claude Sonnet 4.5 (previous sonnet)GPT-5.6 Luna vs GPT-5 mini (previous gpt-mini)GPT-5 vs Claude Sonnet 5 GPT-5.6 Terra vs Claude Sonnet 5 Claude Opus 4.5 vs Claude Sonnet 5 GPT-4.5 Orion vs Claude Sonnet 5

Claude Sonnet 5 vs GPT-5.6 Luna benchmark

Interactive Comparison Diagram

Matchup Breakdown

Tug-of-War Matchup Matrix

Category wins across intelligence, speed, and pricing efficiency.

Claude Sonnet 5 (5)vsGPT-5.6 Luna (5)

Claude Sonnet 5: 5W (50%)Overall: Even matchupGPT-5.6 Luna: 5W (50%)

← Claude Sonnet 5GPT-5.6 Luna →

Claude Sonnet 5 (5/5)

Intelligence & Reasoning

Preference Elo, Coding proficiency, SWE-bench & LiveBench accuracy

Preference Elo

1,556vs1,466

Coding Elo

1,562vs1,458

SWE-bench

73.8%vs61.8%

LiveBench

70.4%vs64.2%

GPQA Diamond

82.8%vs75.4%

Claude Sonnet 5: 5WGPT-5.6 Luna: 0W

GPT-5.6 Luna (2/2)

Speed & Latency

Generation throughput and time to first token responsiveness

Output speed

118 tok/svs188 tok/s

Time to first token

175 msvs88 ms

Claude Sonnet 5: 0WGPT-5.6 Luna: 2W

GPT-5.6 Luna (3/3)

Pricing & Capacity

Cost per million tokens and max context window length

Output price

$10/1Mvs$0.6/1M

Input price

$2/1Mvs$0.1/1M

Context window

1Mvs1.1M

Claude Sonnet 5: 0WGPT-5.6 Luna: 3W

Recommended Workload Routing

Repo / coding agentsClaude Sonnet 5

Higher SWE-bench (73.8%).

High-volume chatGPT-5.6 Luna

Lower output list price ($0.6/1M).

Voice / low-latency UIGPT-5.6 Luna

Lower TTFT (88 ms).

Long-document RAGGPT-5.6 Luna

Larger window (1.1M).

Screenshots / visionClaude Sonnet 5

Both accept images. Defaulting to the higher-Elo side (Claude Sonnet 5).

Target Workload	Recommended Pick	Evaluation Rationale
Repo / coding agents	Claude Sonnet 5	Higher SWE-bench (73.8%).
High-volume chat	GPT-5.6 Luna	Lower output list price ($0.6/1M).
Voice / low-latency UI	GPT-5.6 Luna	Lower TTFT (88 ms).
Long-document RAG	GPT-5.6 Luna	Larger window (1.1M).
Screenshots / vision	Claude Sonnet 5	Both accept images. Defaulting to the higher-Elo side (Claude Sonnet 5).

Frequently Asked Questions

Which is better overall, Claude Sonnet 5 or GPT-5.6 Luna?

Claude Sonnet 5 has the higher preference Elo in our latest snapshot (1,556). “Better” still depends on coding, price, and latency — see the table.

Which is better at coding, Claude Sonnet 5 or GPT-5.6 Luna?

Claude Sonnet 5 leads SWE-bench at 73.8% vs 61.8%. SWE-bench is one harness, not your repo.

Which is cheaper to run in production?

GPT-5.6 Luna output tokens are $0.6/1M versus $10/1M. Input prices and retry rates still move the real bill.

Which is faster, Claude Sonnet 5 or GPT-5.6 Luna?

GPT-5.6 Luna has the lower time-to-first-token (88 ms vs 175 ms). Tokens/sec is a separate column if you care about long completions.

Which has the larger context window?

GPT-5.6 Luna accepts 1.1M tokens versus 1M.

Can I self-host either model?

Neither model is marked open-weights here. You are comparing hosted APIs.

Are these scores from CompareLLM’s own evals?

No. V1 aggregates public leaderboards (and optional first-party latency pings). Each cell names its source and date. Read /methodology.

What does preference Elo mean on this page?

Preference Elo is a crowd vote from LMArena / Arena. People see two hidden answers and pick the one they like more. The model that wins more often gets a higher Elo. That means people preferred it — not that it passed a school test. It is not SWE-bench, not accuracy, and not a number we invent. Claude Sonnet 5 and GPT-5.6 Luna Elo cells are dated snapshots from the named source — we do not compute Arena ourselves.

Swap or Add Any Model to this Matchup

Interactive Comparison Diagram

Tug-of-War Matchup Matrix

Intelligence & Reasoning

Speed & Latency

Pricing & Capacity

Multi-Dimensional Capability Radar

Claude Sonnet 5

GPT-5.6 Luna

GPT-5.6 Luna

Full Benchmark Score Matrix

Workload Cost & Savings Calculator

Key Selection Recommendations

Recommended Workload Routing

Related Editorial Dispatches & Benchmark Notes

Sonnet vs Opus in 2026: same family, different invoice

Claude Sonnet 5 at $2/$10: the 2026 Anthropic workhorse

GPT-5.6 Luna’s 80% cut: $0.20/$1.20 for volume chat

Claude Sonnet 4.5 is the previous workhorse — still a valid vs baseline

Cast Your Matchup Vote

Community Discussions (0)

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CompareLLM Matrix

Claude Sonnet 5

GPT-5.6 Luna

Frequently Asked Questions

Related news

Similar Head-to-Head Comparisons

Swap or Add Any Model to this Matchup

Interactive Comparison Diagram

Tug-of-War Matchup Matrix

Intelligence & Reasoning

Speed & Latency

Pricing & Capacity

Multi-Dimensional Capability Radar

Claude Sonnet 5

GPT-5.6 Luna

GPT-5.6 Luna

Full Benchmark Score Matrix

Workload Cost & Savings Calculator

Key Selection Recommendations

Recommended Workload Routing

Related Editorial Dispatches & Benchmark Notes

Sonnet vs Opus in 2026: same family, different invoice

Claude Sonnet 5 at $2/$10: the 2026 Anthropic workhorse

GPT-5.6 Luna’s 80% cut: $0.20/$1.20 for volume chat

Claude Sonnet 4.5 is the previous workhorse — still a valid vs baseline

Cast Your Matchup Vote

Community Discussions (0)

Share card

CompareLLM Matrix

Claude Sonnet 5

GPT-5.6 Luna

Frequently Asked Questions

Related news

Similar Head-to-Head Comparisons