Pairwise benchmark snapshot · Aug 16, 2026

Claude 3.5 Sonnet vs Claude Opus 4.5 benchmark

Name: Claude 3.5 Sonnet vs Claude Opus 4.5 AI benchmark comparison
Creator: CompareLLM
License: https://creativecommons.org/licenses/by/4.0/

This page compares Claude 3.5 Sonnet (Anthropic) and Claude Opus 4.5 (Anthropic) using the latest snapshots we have as of Aug 16, 2026. On preference Elo, Claude Opus 4.5 is ahead by 288 points (1,568 vs 1,280; seed-bootstrap (Aug 1, 2026)). On SWE-bench coding, Claude Opus 4.5 resolves 76.8% versus 49% (seed-bootstrap (Aug 1, 2026)). Claude 3.5 Sonnet streams faster (80 tok/s) while Claude 3.5 Sonnet is the cheaper output token ($15/1M). Claude 3.5 Sonnet has the larger context window (200k 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 3.5 Sonnet

2024 workhorse. Still a high-intent compare against GPT-4o.

Elo 1,280$15/1M out

Anthropic

Claude Opus 4.5

Anthropic frontier coding and computer-use model. SWE-bench leader on the official mini-SWE-agent harness in the Feb 2026 refresh.

Elo 1,568$25/1M out

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Quick vs:vs Claude Opus 4.6 vs Claude Sonnet 4.5 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 3.5 Sonnet (4)vsClaude Opus 4.5 (5)

Claude 3.5 Sonnet: 4W (44%)Overall: Claude Opus 4.5Claude Opus 4.5: 5W (56%)

← Claude 3.5 Sonnet1 tiesClaude Opus 4.5 →

Claude Opus 4.5 (5/5)

Intelligence & Reasoning

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

Preference Elo

1,280vs1,568

Coding Elo

—vs1,574

SWE-bench

49%vs76.8%

LiveBench

52.1%vs71.2%

GPQA Diamond

65%vs84.1%

Claude 3.5 Sonnet: 0WClaude Opus 4.5: 5W

Claude 3.5 Sonnet (2/2)

Speed & Latency

Generation throughput and time to first token responsiveness

Output speed

80 tok/svs62 tok/s

Time to first token

280 msvs380 ms

Claude 3.5 Sonnet: 2WClaude Opus 4.5: 0W

Claude 3.5 Sonnet (2/3)

Pricing & Capacity

Cost per million tokens and max context window length

Output price

$15/1Mvs$25/1M

Input price

$3/1Mvs$5/1M

Context window

200kvs200k

Claude 3.5 Sonnet: 2WClaude Opus 4.5: 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 AdvantageClaude Opus 4.5 3/6

Preference Elo

Claude Opus 4.5

288 pts advantage

Throughput Speed

Claude 3.5 Sonnet

18 tok/s faster

Price Efficiency

Claude 3.5 Sonnet

$10.00/1M cheaper

Full Benchmark Score Matrix

—

Elo

High is better

1,280

EloHigh is better

1,568+23%

Code Elo

High is better

—

Code EloHigh is better

1,574

LiveBench

High is better

52.1%

LiveBenchHigh is better

71.2%+37%

SWE-bench

High is better

49%

SWE-benchHigh is better

76.8%+57%

GPQA

High is better

65%

GPQAHigh is better

84.1%+29%

TTFT

Low is better

+36%280 ms

TTFTLow is better

380 ms

Speed

High is better

+29%80 tok/s

SpeedHigh is better

62 tok/s

In $

Low is better

+67%$3/1M

In $Low is better

$5/1M

Out $

Low is better

+67%$15/1M

Out $Low is better

$25/1M

Context

High is better

200k

ContextHigh is better

200k

Interactive Simulator

Workload Cost & Savings Calculator

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

Save up to 40% with Claude 3.5 Sonnet

Monthly Volume50M tokens/mo

Quick Presets:

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

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

Claude 3.5 Sonnet$330.00 / mo

In: $105.00Out: $225.00

Claude Opus 4.5$550.00 / mo

In: $175.00Out: $375.00

Estimated Cost Delta

Claude 3.5 Sonnet is estimated to save $220.00/month ($2,640/year).

Based on 50M tokens (30% gen)

Key Selection Recommendations

1
Claude Opus 4.5:Pick Claude Opus 4.5 when repo-level coding accuracy is the constraint.
2
Claude 3.5 Sonnet:Pick Claude 3.5 Sonnet when you are optimizing output cost.
3
Claude 3.5 Sonnet:Pick Claude 3.5 Sonnet when time-to-first-token matters more than peak Elo.

Recommended Workload Routing

Repo / coding agentsClaude Opus 4.5

Higher SWE-bench (76.8%).

High-volume chatClaude 3.5 Sonnet

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

Voice / low-latency UIClaude 3.5 Sonnet

Lower TTFT (280 ms).

Long-document RAGClaude 3.5 Sonnet

Larger window (200k).

Screenshots / visionClaude Opus 4.5

Both accept images. Defaulting to the higher-Elo side (Claude Opus 4.5).

Target Workload	Recommended Pick	Evaluation Rationale
Repo / coding agents	Claude Opus 4.5	Higher SWE-bench (76.8%).
High-volume chat	Claude 3.5 Sonnet	Lower output list price ($15/1M).
Voice / low-latency UI	Claude 3.5 Sonnet	Lower TTFT (280 ms).
Long-document RAG	Claude 3.5 Sonnet	Larger window (200k).
Screenshots / vision	Claude Opus 4.5	Both accept images. Defaulting to the higher-Elo side (Claude Opus 4.5).

Related Editorial Dispatches & Benchmark Notes

View all news

launchFeb 20, 2026

Claude Opus 4.5 and the Feb 2026 SWE-bench row we still cite

The Feb refresh made 4.5 a coding reference. Newer Opus SKUs exist; this row stays as the dated harness point.

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LIVE

Anthropic

Claude 3.5 Sonnet

Elo 1,280

LiveBench52.1%

SWE-bench49%

Speed80 tok/s

Output cost$15/1M

Anthropic

Claude Opus 4.5

Elo 1,568

LiveBench71.2%

SWE-bench76.8%

Speed62 tok/s

Output cost$25/1M

Frequently Asked Questions

Which is better overall, Claude 3.5 Sonnet or Claude Opus 4.5?: Claude Opus 4.5 has the higher preference Elo in our latest snapshot (1,568). “Better” still depends on coding, price, and latency — see the table.
Which is better at coding, Claude 3.5 Sonnet or Claude Opus 4.5?: Claude Opus 4.5 leads SWE-bench at 76.8% vs 49%. SWE-bench is one harness, not your repo.
Which is cheaper to run in production?: Claude 3.5 Sonnet output tokens are $15/1M versus $25/1M. Input prices and retry rates still move the real bill.
Which is faster, Claude 3.5 Sonnet or Claude Opus 4.5?: Claude 3.5 Sonnet has the lower time-to-first-token (280 ms vs 380 ms). Tokens/sec is a separate column if you care about long completions.
Which has the larger context window?: Claude 3.5 Sonnet accepts 200k tokens versus 200k.
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 3.5 Sonnet and Claude Opus 4.5 Elo cells are dated snapshots from the named source — we do not compute Arena ourselves.

Similar Head-to-Head Comparisons

All Claude 3.5 Sonnet matchups →|All Claude Opus 4.5 matchups →

Claude 3.5 Sonnet vs Claude 3.7 Sonnet (next sonnet)Claude Opus 4.5 vs Claude Opus 4 (previous opus)Claude Opus 4.5 vs Claude Opus 4.6 (next opus)Claude Sonnet 4.5 vs Claude Opus 4.5 Claude Opus 5 vs Claude Opus 4.5 Claude Fable 5 vs Claude Opus 4.5

Claude 3.5 Sonnet vs Claude Opus 4.5 benchmark

Interactive Comparison Diagram

Matchup Breakdown

Tug-of-War Matchup Matrix

Category wins across intelligence, speed, and pricing efficiency.

Claude 3.5 Sonnet (4)vsClaude Opus 4.5 (5)

Claude 3.5 Sonnet: 4W (44%)Overall: Claude Opus 4.5Claude Opus 4.5: 5W (56%)

← Claude 3.5 Sonnet1 tiesClaude Opus 4.5 →

Claude Opus 4.5 (5/5)

Intelligence & Reasoning

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

Preference Elo

1,280vs1,568

Coding Elo

—vs1,574

SWE-bench

49%vs76.8%

LiveBench

52.1%vs71.2%

GPQA Diamond

65%vs84.1%

Claude 3.5 Sonnet: 0WClaude Opus 4.5: 5W

Claude 3.5 Sonnet (2/2)

Speed & Latency

Generation throughput and time to first token responsiveness

Output speed

80 tok/svs62 tok/s

Time to first token

280 msvs380 ms

Claude 3.5 Sonnet: 2WClaude Opus 4.5: 0W

Claude 3.5 Sonnet (2/3)

Pricing & Capacity

Cost per million tokens and max context window length

Output price

$15/1Mvs$25/1M

Input price

$3/1Mvs$5/1M

Context window

200kvs200k

Claude 3.5 Sonnet: 2WClaude Opus 4.5: 0W

Recommended Workload Routing

Repo / coding agentsClaude Opus 4.5

Higher SWE-bench (76.8%).

High-volume chatClaude 3.5 Sonnet

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

Voice / low-latency UIClaude 3.5 Sonnet

Lower TTFT (280 ms).

Long-document RAGClaude 3.5 Sonnet

Larger window (200k).

Screenshots / visionClaude Opus 4.5

Both accept images. Defaulting to the higher-Elo side (Claude Opus 4.5).

Target Workload	Recommended Pick	Evaluation Rationale
Repo / coding agents	Claude Opus 4.5	Higher SWE-bench (76.8%).
High-volume chat	Claude 3.5 Sonnet	Lower output list price ($15/1M).
Voice / low-latency UI	Claude 3.5 Sonnet	Lower TTFT (280 ms).
Long-document RAG	Claude 3.5 Sonnet	Larger window (200k).
Screenshots / vision	Claude Opus 4.5	Both accept images. Defaulting to the higher-Elo side (Claude Opus 4.5).

Frequently Asked Questions

Which is better overall, Claude 3.5 Sonnet or Claude Opus 4.5?

Claude Opus 4.5 has the higher preference Elo in our latest snapshot (1,568). “Better” still depends on coding, price, and latency — see the table.

Which is better at coding, Claude 3.5 Sonnet or Claude Opus 4.5?

Claude Opus 4.5 leads SWE-bench at 76.8% vs 49%. SWE-bench is one harness, not your repo.

Which is cheaper to run in production?

Claude 3.5 Sonnet output tokens are $15/1M versus $25/1M. Input prices and retry rates still move the real bill.

Which is faster, Claude 3.5 Sonnet or Claude Opus 4.5?

Claude 3.5 Sonnet has the lower time-to-first-token (280 ms vs 380 ms). Tokens/sec is a separate column if you care about long completions.

Which has the larger context window?

Claude 3.5 Sonnet accepts 200k tokens versus 200k.

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 3.5 Sonnet and Claude Opus 4.5 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 Opus 4.5

Claude 3.5 Sonnet

Claude 3.5 Sonnet

Full Benchmark Score Matrix

Workload Cost & Savings Calculator

Key Selection Recommendations

Recommended Workload Routing

Related Editorial Dispatches & Benchmark Notes

Claude Opus 4.5 and the Feb 2026 SWE-bench row we still cite

Cast Your Matchup Vote

Community Discussions (0)

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CompareLLM Matrix

Claude 3.5 Sonnet

Claude Opus 4.5

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 Opus 4.5

Claude 3.5 Sonnet

Claude 3.5 Sonnet

Full Benchmark Score Matrix

Workload Cost & Savings Calculator

Key Selection Recommendations

Recommended Workload Routing

Related Editorial Dispatches & Benchmark Notes

Claude Opus 4.5 and the Feb 2026 SWE-bench row we still cite

Cast Your Matchup Vote

Community Discussions (0)

Share card

CompareLLM Matrix

Claude 3.5 Sonnet

Claude Opus 4.5

Frequently Asked Questions

Related news

Similar Head-to-Head Comparisons