Pairwise benchmark snapshot · Aug 16, 2026

GPT-5.6 Luna vs Grok 4.6 benchmark

Name: GPT-5.6 Luna vs Grok 4.6 AI benchmark comparison
Creator: CompareLLM
License: https://creativecommons.org/licenses/by/4.0/

This page compares GPT-5.6 Luna (OpenAI) and Grok 4.6 (xAI) using the latest snapshots we have as of Aug 16, 2026. On preference Elo, Grok 4.6 is ahead by 126 points (1,592 vs 1,466; seed-bootstrap (Aug 16, 2026)). On SWE-bench coding, Grok 4.6 resolves 69.1% 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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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

xAI

Grok 4.6

xAI Aug 12 2026 post-training refresh of Grok 4.5. Same $2/$6 API price, 500k context, stronger agentic traces.

Elo 1,592$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.

GPT-5.6 Luna (5)vsGrok 4.6 (5)

GPT-5.6 Luna: 5W (50%)Overall: Even matchupGrok 4.6: 5W (50%)

← GPT-5.6 LunaGrok 4.6 →

Grok 4.6 (5/5)

Intelligence & Reasoning

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

Preference Elo

1,466vs1,592

Coding Elo

1,458vs1,568

SWE-bench

61.8%vs69.1%

LiveBench

64.2%vs71.4%

GPQA Diamond

75.4%vs84.6%

GPT-5.6 Luna: 0WGrok 4.6: 5W

GPT-5.6 Luna (2/2)

Speed & Latency

Generation throughput and time to first token responsiveness

Output speed

188 tok/svs118 tok/s

Time to first token

88 msvs195 ms

GPT-5.6 Luna: 2WGrok 4.6: 0W

GPT-5.6 Luna (3/3)

Pricing & Capacity

Cost per million tokens and max context window length

Output price

$0.6/1Mvs$6/1M

Input price

$0.1/1Mvs$2/1M

Context window

1.1Mvs500k

GPT-5.6 Luna: 3WGrok 4.6: 0W

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

Grok 4.6

126 pts advantage

Throughput Speed

GPT-5.6 Luna

70 tok/s faster

Price Efficiency

GPT-5.6 Luna

$5.40/1M cheaper

Full Benchmark Score Matrix

—

Elo

High is better

1,466

EloHigh is better

1,592+9%

Code Elo

High is better

1,458

Code EloHigh is better

1,568+8%

LiveBench

High is better

64.2%

LiveBenchHigh is better

71.4%+11%

SWE-bench

High is better

61.8%

SWE-benchHigh is better

69.1%+12%

GPQA

High is better

75.4%

GPQAHigh is better

84.6%+12%

TTFT

Low is better

+122%88 ms

TTFTLow is better

195 ms

Speed

High is better

+59%188 tok/s

SpeedHigh is better

118 tok/s

In $

Low is better

+1900%$0.1/1M

In $Low is better

$2/1M

Out $

Low is better

+900%$0.6/1M

Out $Low is better

$6/1M

Context

High is better

+110%1.1M

ContextHigh is better

500k

Interactive Simulator

Workload Cost & Savings Calculator

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

Save up to 92% 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)

GPT-5.6 Luna$12.50 / mo

In: $3.50Out: $9.00

Grok 4.6$160.00 / mo

In: $70.00Out: $90.00

Estimated Cost Delta

GPT-5.6 Luna is estimated to save $147.50/month ($1,770/year).

Based on 50M tokens (30% gen)

Key Selection Recommendations

1
Grok 4.6:Pick Grok 4.6 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 agentsGrok 4.6

Higher SWE-bench (69.1%).

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 / visionGrok 4.6

Both accept images. Defaulting to the higher-Elo side (Grok 4.6).

Target Workload	Recommended Pick	Evaluation Rationale
Repo / coding agents	Grok 4.6	Higher SWE-bench (69.1%).
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	Grok 4.6	Both accept images. Defaulting to the higher-Elo side (Grok 4.6).

Related Editorial Dispatches & Benchmark Notes

View all news

compareAug 12, 2026

Grok vs ChatGPT: price and Elo, not a personality contest

Brand hub remaps to top xAI vs top OpenAI. After Aug 12 that is Grok 4.6 vs Sol.

launchAug 12, 2026

Grok 4.6 (Aug 12): post-training refresh, same $2/$6 list

xAI’s Aug 12 2026 refresh of Grok 4.5. 500k context. The Grok vs ChatGPT hub remaps here.

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.

launchAug 8, 2025

GPT-5 mini: the 2025 distill still useful as a cheap OpenAI baseline

High-volume agents that cannot pay Sol. Compare to Luna before you assume the new cheap SKU wins.

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LIVE

OpenAI

GPT-5.6 Luna

Elo 1,466

LiveBench64.2%

SWE-bench61.8%

Speed188 tok/s

Output cost$0.6/1M

xAI

Grok 4.6

Elo 1,592

LiveBench71.4%

SWE-bench69.1%

Speed118 tok/s

Output cost$6/1M

Frequently Asked Questions

Which is better overall, GPT-5.6 Luna or Grok 4.6?: Grok 4.6 has the higher preference Elo in our latest snapshot (1,592). “Better” still depends on coding, price, and latency — see the table.
Which is better at coding, GPT-5.6 Luna or Grok 4.6?: Grok 4.6 leads SWE-bench at 69.1% 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 $6/1M. Input prices and retry rates still move the real bill.
Which is faster, GPT-5.6 Luna or Grok 4.6?: GPT-5.6 Luna has the lower time-to-first-token (88 ms vs 195 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 500k.
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. GPT-5.6 Luna and Grok 4.6 Elo cells are dated snapshots from the named source — we do not compute Arena ourselves.

Similar Head-to-Head Comparisons

All GPT-5.6 Luna matchups →|All Grok 4.6 matchups →

GPT-5.6 Luna vs GPT-5 mini (previous gpt-mini)Grok 4.6 vs Grok 4 (previous grok)GPT-4.5 Orion vs Grok 4.6 GPT-5.6 Terra vs Grok 4.6 GPT-5 vs Grok 4.6 GPT-5.6 Sol vs Grok 4.6

GPT-5.6 Luna vs Grok 4.6 benchmark

Interactive Comparison Diagram

Matchup Breakdown

Tug-of-War Matchup Matrix

Category wins across intelligence, speed, and pricing efficiency.

GPT-5.6 Luna (5)vsGrok 4.6 (5)

GPT-5.6 Luna: 5W (50%)Overall: Even matchupGrok 4.6: 5W (50%)

← GPT-5.6 LunaGrok 4.6 →

Grok 4.6 (5/5)

Intelligence & Reasoning

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

Preference Elo

1,466vs1,592

Coding Elo

1,458vs1,568

SWE-bench

61.8%vs69.1%

LiveBench

64.2%vs71.4%

GPQA Diamond

75.4%vs84.6%

GPT-5.6 Luna: 0WGrok 4.6: 5W

GPT-5.6 Luna (2/2)

Speed & Latency

Generation throughput and time to first token responsiveness

Output speed

188 tok/svs118 tok/s

Time to first token

88 msvs195 ms

GPT-5.6 Luna: 2WGrok 4.6: 0W

GPT-5.6 Luna (3/3)

Pricing & Capacity

Cost per million tokens and max context window length

Output price

$0.6/1Mvs$6/1M

Input price

$0.1/1Mvs$2/1M

Context window

1.1Mvs500k

GPT-5.6 Luna: 3WGrok 4.6: 0W

Recommended Workload Routing

Repo / coding agentsGrok 4.6

Higher SWE-bench (69.1%).

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 / visionGrok 4.6

Both accept images. Defaulting to the higher-Elo side (Grok 4.6).

Target Workload	Recommended Pick	Evaluation Rationale
Repo / coding agents	Grok 4.6	Higher SWE-bench (69.1%).
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	Grok 4.6	Both accept images. Defaulting to the higher-Elo side (Grok 4.6).

Frequently Asked Questions

Which is better overall, GPT-5.6 Luna or Grok 4.6?

Grok 4.6 has the higher preference Elo in our latest snapshot (1,592). “Better” still depends on coding, price, and latency — see the table.

Which is better at coding, GPT-5.6 Luna or Grok 4.6?

Grok 4.6 leads SWE-bench at 69.1% 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 $6/1M. Input prices and retry rates still move the real bill.

Which is faster, GPT-5.6 Luna or Grok 4.6?

GPT-5.6 Luna has the lower time-to-first-token (88 ms vs 195 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 500k.

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. GPT-5.6 Luna and Grok 4.6 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

Grok 4.6

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

Grok vs ChatGPT: price and Elo, not a personality contest

Grok 4.6 (Aug 12): post-training refresh, same $2/$6 list

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

GPT-5 mini: the 2025 distill still useful as a cheap OpenAI baseline

Cast Your Matchup Vote

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CompareLLM Matrix

GPT-5.6 Luna

Grok 4.6

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

Grok 4.6

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

Grok vs ChatGPT: price and Elo, not a personality contest

Grok 4.6 (Aug 12): post-training refresh, same $2/$6 list

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

GPT-5 mini: the 2025 distill still useful as a cheap OpenAI baseline

Cast Your Matchup Vote

Community Discussions (0)

Share card

CompareLLM Matrix

GPT-5.6 Luna

Grok 4.6

Frequently Asked Questions

Related news

Similar Head-to-Head Comparisons