Pairwise benchmark snapshot · Aug 16, 2026

Claude Sonnet 4.5 vs Kimi K3 benchmark

Name: Claude Sonnet 4.5 vs Kimi K3 AI benchmark comparison
Creator: CompareLLM
License: https://creativecommons.org/licenses/by/4.0/

This page compares Claude Sonnet 4.5 (Anthropic) and Kimi K3 (Moonshot) using the latest snapshots we have as of Aug 16, 2026. On preference Elo, Kimi K3 is ahead by 4 points (1,528 vs 1,524; seed-bootstrap (Aug 1, 2026)). On SWE-bench coding, Kimi K3 resolves 73.8% versus 70.1% (seed-bootstrap (Aug 1, 2026)). Claude Sonnet 4.5 streams faster (88 tok/s) while Claude Sonnet 4.5 is the cheaper output token ($15/1M). Kimi K3 has the larger context window (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 4.5

Workhorse Anthropic model: most of Opus coding quality at a mid-tier price.

Elo 1,524$15/1M out

Moonshot

Kimi K3

Moonshot AI frontier flagship reasoning and agent swarm model with 256k context and top-tier SWE-bench coding capability.

Elo 1,528$15/1M out

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Model A

Model B

Quick vs:vs Claude Opus 4.5 vs Claude Opus 4.6 vs Claude 3.7 Sonnet vs GPT-5

Interactive Comparison Diagram

Matchup Breakdown

Tug-of-War Matchup Matrix

Category wins across intelligence, speed, and pricing efficiency.

Claude Sonnet 4.5 (2)vsKimi K3 (6)

Claude Sonnet 4.5: 2W (25%)Overall: Kimi K3Kimi K3: 6W (75%)

← Claude Sonnet 4.52 tiesKimi K3 →

Kimi K3 (5/5)

Intelligence & Reasoning

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

Preference Elo

1,524vs1,528

Coding Elo

1,531vs1,535

SWE-bench

70.1%vs73.8%

LiveBench

67.4%vs69.5%

GPQA Diamond

80.2%vs88.4%

Claude Sonnet 4.5: 0WKimi K3: 5W

Claude Sonnet 4.5 (2/2)

Speed & Latency

Generation throughput and time to first token responsiveness

Output speed

88 tok/svs68 tok/s

Time to first token

240 msvs290 ms

Claude Sonnet 4.5: 2WKimi K3: 0W

Kimi K3 (1/3)

Pricing & Capacity

Cost per million tokens and max context window length

Output price

$15/1Mvs$15/1M

Input price

$3/1Mvs$3/1M

Context window

1Mvs1M

Claude Sonnet 4.5: 0WKimi K3: 1W

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 AdvantageKimi K3 4/6

Preference Elo

Kimi K3

4 pts advantage

Throughput Speed

Claude Sonnet 4.5

20 tok/s faster

Price Efficiency

Claude Sonnet 4.5

Same token price

Full Benchmark Score Matrix

—

Elo

High is better

1,524

EloHigh is better

1,528

Code Elo

High is better

1,531

Code EloHigh is better

1,535

LiveBench

High is better

67.4%

LiveBenchHigh is better

69.5%+3%

SWE-bench

High is better

70.1%

SWE-benchHigh is better

73.8%+5%

GPQA

High is better

80.2%

GPQAHigh is better

88.4%+10%

TTFT

Low is better

+21%240 ms

TTFTLow is better

290 ms

Speed

High is better

+29%88 tok/s

SpeedHigh is better

68 tok/s

In $

Low is better

$3/1M

In $Low is better

$3/1M

Out $

Low is better

$15/1M

Out $Low is better

$15/1M

Context

High is better

ContextHigh is better

1M+5%

Interactive Simulator

Workload Cost & Savings Calculator

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

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 4.5$330.00 / mo

In: $105.00Out: $225.00

Kimi K3$330.00 / mo

In: $105.00Out: $225.00

Key Selection Recommendations

1
Kimi K3:Pick Kimi K3 when repo-level coding accuracy is the constraint.
2
Claude Sonnet 4.5:Pick Claude Sonnet 4.5 when you are optimizing output cost.
3
Claude Sonnet 4.5:Pick Claude Sonnet 4.5 when time-to-first-token matters more than peak Elo.

Recommended Workload Routing

Repo / coding agentsKimi K3

Higher SWE-bench (73.8%).

High-volume chatClaude Sonnet 4.5

Lower output list price ($15/1M).

Voice / low-latency UIClaude Sonnet 4.5

Lower TTFT (240 ms).

Long-document RAGKimi K3

Larger window (1M).

Screenshots / visionKimi K3

Both accept images. Defaulting to the higher-Elo side (Kimi K3).

Target Workload	Recommended Pick	Evaluation Rationale
Repo / coding agents	Kimi K3	Higher SWE-bench (73.8%).
High-volume chat	Claude Sonnet 4.5	Lower output list price ($15/1M).
Voice / low-latency UI	Claude Sonnet 4.5	Lower TTFT (240 ms).
Long-document RAG	Kimi K3	Larger window (1M).
Screenshots / vision	Kimi K3	Both accept images. Defaulting to the higher-Elo side (Kimi K3).

Related Editorial Dispatches & Benchmark Notes

View all news

launchJun 8, 2026

Kimi K3: Moonshot’s long-context open-weight competitive row

Jun 2026. The Kimi vs GPT hub remaps to the top Moonshot Elo vs top OpenAI 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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CompareLLM Matrix

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LIVE

Anthropic

Claude Sonnet 4.5

Elo 1,524

LiveBench67.4%

SWE-bench70.1%

Speed88 tok/s

Output cost$15/1M

Moonshot

Kimi K3

Elo 1,528

LiveBench69.5%

SWE-bench73.8%

Speed68 tok/s

Output cost$15/1M

Frequently Asked Questions

Which is better overall, Claude Sonnet 4.5 or Kimi K3?: Kimi K3 has the higher preference Elo in our latest snapshot (1,528). “Better” still depends on coding, price, and latency — see the table.
Which is better at coding, Claude Sonnet 4.5 or Kimi K3?: Kimi K3 leads SWE-bench at 73.8% vs 70.1%. SWE-bench is one harness, not your repo.
Which is cheaper to run in production?: Claude Sonnet 4.5 output tokens are $15/1M versus $15/1M. Input prices and retry rates still move the real bill.
Which is faster, Claude Sonnet 4.5 or Kimi K3?: Claude Sonnet 4.5 has the lower time-to-first-token (240 ms vs 290 ms). Tokens/sec is a separate column if you care about long completions.
Which has the larger context window?: Kimi K3 accepts 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 4.5 and Kimi K3 Elo cells are dated snapshots from the named source — we do not compute Arena ourselves.

Similar Head-to-Head Comparisons

All Claude Sonnet 4.5 matchups →|All Kimi K3 matchups →

Claude Sonnet 4.5 vs Claude Sonnet 4 (previous sonnet)Claude Sonnet 4.5 vs Claude Sonnet 5 (next sonnet)Kimi K3 vs MoonshotAI: Kimi K2.5 (previous kimi)Claude Sonnet 5 vs Kimi K3 Claude Opus 4.5 vs Kimi K3 Claude Opus 4.6 vs Kimi K3

Claude Sonnet 4.5 vs Kimi K3 benchmark

Interactive Comparison Diagram

Matchup Breakdown

Tug-of-War Matchup Matrix

Category wins across intelligence, speed, and pricing efficiency.

Claude Sonnet 4.5 (2)vsKimi K3 (6)

Claude Sonnet 4.5: 2W (25%)Overall: Kimi K3Kimi K3: 6W (75%)

← Claude Sonnet 4.52 tiesKimi K3 →

Kimi K3 (5/5)

Intelligence & Reasoning

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

Preference Elo

1,524vs1,528

Coding Elo

1,531vs1,535

SWE-bench

70.1%vs73.8%

LiveBench

67.4%vs69.5%

GPQA Diamond

80.2%vs88.4%

Claude Sonnet 4.5: 0WKimi K3: 5W

Claude Sonnet 4.5 (2/2)

Speed & Latency

Generation throughput and time to first token responsiveness

Output speed

88 tok/svs68 tok/s

Time to first token

240 msvs290 ms

Claude Sonnet 4.5: 2WKimi K3: 0W

Kimi K3 (1/3)

Pricing & Capacity

Cost per million tokens and max context window length

Output price

$15/1Mvs$15/1M

Input price

$3/1Mvs$3/1M

Context window

1Mvs1M

Claude Sonnet 4.5: 0WKimi K3: 1W

Recommended Workload Routing

Repo / coding agentsKimi K3

Higher SWE-bench (73.8%).

High-volume chatClaude Sonnet 4.5

Lower output list price ($15/1M).

Voice / low-latency UIClaude Sonnet 4.5

Lower TTFT (240 ms).

Long-document RAGKimi K3

Larger window (1M).

Screenshots / visionKimi K3

Both accept images. Defaulting to the higher-Elo side (Kimi K3).

Target Workload	Recommended Pick	Evaluation Rationale
Repo / coding agents	Kimi K3	Higher SWE-bench (73.8%).
High-volume chat	Claude Sonnet 4.5	Lower output list price ($15/1M).
Voice / low-latency UI	Claude Sonnet 4.5	Lower TTFT (240 ms).
Long-document RAG	Kimi K3	Larger window (1M).
Screenshots / vision	Kimi K3	Both accept images. Defaulting to the higher-Elo side (Kimi K3).

Frequently Asked Questions

Which is better overall, Claude Sonnet 4.5 or Kimi K3?

Kimi K3 has the higher preference Elo in our latest snapshot (1,528). “Better” still depends on coding, price, and latency — see the table.

Which is better at coding, Claude Sonnet 4.5 or Kimi K3?

Kimi K3 leads SWE-bench at 73.8% vs 70.1%. SWE-bench is one harness, not your repo.

Which is cheaper to run in production?

Claude Sonnet 4.5 output tokens are $15/1M versus $15/1M. Input prices and retry rates still move the real bill.

Which is faster, Claude Sonnet 4.5 or Kimi K3?

Claude Sonnet 4.5 has the lower time-to-first-token (240 ms vs 290 ms). Tokens/sec is a separate column if you care about long completions.

Which has the larger context window?

Kimi K3 accepts 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 4.5 and Kimi K3 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

Kimi K3

Claude Sonnet 4.5

Claude Sonnet 4.5

Full Benchmark Score Matrix

Workload Cost & Savings Calculator

Key Selection Recommendations

Recommended Workload Routing

Related Editorial Dispatches & Benchmark Notes

Kimi K3: Moonshot’s long-context open-weight competitive row

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 4.5

Kimi K3

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

Kimi K3

Claude Sonnet 4.5

Claude Sonnet 4.5

Full Benchmark Score Matrix

Workload Cost & Savings Calculator

Key Selection Recommendations

Recommended Workload Routing

Related Editorial Dispatches & Benchmark Notes

Kimi K3: Moonshot’s long-context open-weight competitive row

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 4.5

Kimi K3

Frequently Asked Questions

Related news

Similar Head-to-Head Comparisons