Pairwise benchmark snapshot · Aug 16, 2026

Claude Opus 4 vs Gemini 2.5 Flash benchmark

Name: Claude Opus 4 vs Gemini 2.5 Flash AI benchmark comparison
Creator: CompareLLM
License: https://creativecommons.org/licenses/by/4.0/

This page compares Claude Opus 4 (Anthropic) and Gemini 2.5 Flash (Google) using the latest snapshots we have as of Aug 16, 2026. On preference Elo, Claude Opus 4 is ahead by 195 points (1,490 vs 1,295; seed-bootstrap (Aug 1, 2026)). On SWE-bench coding, Claude Opus 4 resolves 72.5% versus 48% (seed-bootstrap (Aug 1, 2026)). Gemini 2.5 Flash streams faster (185 tok/s) while Gemini 2.5 Flash is the cheaper output token ($2.5/1M). Gemini 2.5 Flash 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 Opus 4

First Claude 4 Opus generation. Baseline for opus 4 vs opus 5.

Elo 1,490$75/1M out

Google

Gemini 2.5 Flash

Previous Google speed workhorse.

Elo 1,295$2.5/1M 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 Opus 4 (5)vsGemini 2.5 Flash (5)

Claude Opus 4: 5W (50%)Overall: Even matchupGemini 2.5 Flash: 5W (50%)

← Claude Opus 4Gemini 2.5 Flash →

Claude Opus 4 (5/5)

Intelligence & Reasoning

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

Preference Elo

1,490vs1,295

Coding Elo

1,502vs—

SWE-bench

72.5%vs48%

LiveBench

66.8%vs51.4%

GPQA Diamond

80.4%vs68.2%

Claude Opus 4: 5WGemini 2.5 Flash: 0W

Gemini 2.5 Flash (2/2)

Speed & Latency

Generation throughput and time to first token responsiveness

Output speed

58 tok/svs185 tok/s

Time to first token

390 msvs110 ms

Claude Opus 4: 0WGemini 2.5 Flash: 2W

Gemini 2.5 Flash (3/3)

Pricing & Capacity

Cost per million tokens and max context window length

Output price

$75/1Mvs$2.5/1M

Input price

$15/1Mvs$0.3/1M

Context window

200kvs1M

Claude Opus 4: 0WGemini 2.5 Flash: 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 Opus 4

195 pts advantage

Throughput Speed

Gemini 2.5 Flash

127 tok/s faster

Price Efficiency

Gemini 2.5 Flash

$72.50/1M cheaper

Full Benchmark Score Matrix

—

Elo

High is better

+15%1,490

EloHigh is better

1,295

Code Elo

High is better

1,502

Code EloHigh is better

—

LiveBench

High is better

+30%66.8%

LiveBenchHigh is better

51.4%

SWE-bench

High is better

+51%72.5%

SWE-benchHigh is better

48%

GPQA

High is better

+18%80.4%

GPQAHigh is better

68.2%

TTFT

Low is better

390 ms

TTFTLow is better

110 ms+255%

Speed

High is better

58 tok/s

SpeedHigh is better

185 tok/s+219%

In $

Low is better

$15/1M

In $Low is better

$0.3/1M+4900%

Out $

Low is better

$75/1M

Out $Low is better

$2.5/1M+2900%

Context

High is better

200k

ContextHigh is better

1M+424%

Interactive Simulator

Workload Cost & Savings Calculator

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

Save up to 97% with Gemini 2.5 Flash

Monthly Volume50M tokens/mo

Quick Presets:

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

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

Claude Opus 4$1,650.00 / mo

In: $525.00Out: $1125.00

Gemini 2.5 Flash$48.00 / mo

In: $10.50Out: $37.50

Estimated Cost Delta

Gemini 2.5 Flash is estimated to save $1,602.00/month ($19,224/year).

Based on 50M tokens (30% gen)

Key Selection Recommendations

1
Claude Opus 4:Pick Claude Opus 4 when repo-level coding accuracy is the constraint.
2
Gemini 2.5 Flash:Pick Gemini 2.5 Flash when you are optimizing output cost.
3
Gemini 2.5 Flash:Pick Gemini 2.5 Flash when time-to-first-token matters more than peak Elo.

Recommended Workload Routing

Repo / coding agentsClaude Opus 4

Higher SWE-bench (72.5%).

High-volume chatGemini 2.5 Flash

Lower output list price ($2.5/1M).

Voice / low-latency UIGemini 2.5 Flash

Lower TTFT (110 ms).

Long-document RAGGemini 2.5 Flash

Larger window (1M).

Screenshots / visionClaude Opus 4

Both accept images. Defaulting to the higher-Elo side (Claude Opus 4).

Target Workload	Recommended Pick	Evaluation Rationale
Repo / coding agents	Claude Opus 4	Higher SWE-bench (72.5%).
High-volume chat	Gemini 2.5 Flash	Lower output list price ($2.5/1M).
Voice / low-latency UI	Gemini 2.5 Flash	Lower TTFT (110 ms).
Long-document RAG	Gemini 2.5 Flash	Larger window (1M).
Screenshots / vision	Claude Opus 4	Both accept images. Defaulting to the higher-Elo side (Claude Opus 4).

Related Editorial Dispatches & Benchmark Notes

View all news

launchMar 25, 2025

Gemini 2.5 Flash: previous Google speed workhorse, still a baseline

Useful as a cheap historical compare. 3.7 Flash is the 2026 volume SKU.

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LIVE

Anthropic

Claude Opus 4

Elo 1,490

LiveBench66.8%

SWE-bench72.5%

Speed58 tok/s

Output cost$75/1M

Google

Gemini 2.5 Flash

Elo 1,295

LiveBench51.4%

SWE-bench48%

Speed185 tok/s

Output cost$2.5/1M

Frequently Asked Questions

Which is better overall, Claude Opus 4 or Gemini 2.5 Flash?: Claude Opus 4 has the higher preference Elo in our latest snapshot (1,490). “Better” still depends on coding, price, and latency — see the table.
Which is better at coding, Claude Opus 4 or Gemini 2.5 Flash?: Claude Opus 4 leads SWE-bench at 72.5% vs 48%. SWE-bench is one harness, not your repo.
Which is cheaper to run in production?: Gemini 2.5 Flash output tokens are $2.5/1M versus $75/1M. Input prices and retry rates still move the real bill.
Which is faster, Claude Opus 4 or Gemini 2.5 Flash?: Gemini 2.5 Flash has the lower time-to-first-token (110 ms vs 390 ms). Tokens/sec is a separate column if you care about long completions.
Which has the larger context window?: Gemini 2.5 Flash accepts 1M 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 Opus 4 and Gemini 2.5 Flash Elo cells are dated snapshots from the named source — we do not compute Arena ourselves.

Similar Head-to-Head Comparisons

All Claude Opus 4 matchups →|All Gemini 2.5 Flash matchups →

Claude Opus 4 vs Claude 3 Opus (previous opus)Claude Opus 4 vs Claude Opus 4.5 (next opus)Gemini 2.5 Flash vs Gemini 2.0 Flash Thinking (previous gemini-flash)Gemini 2.5 Flash vs Gemini 3 Flash (next gemini-flash)Gemini 2.0 Flash Thinking vs Claude Opus 4 Gemini 3 Flash vs Claude Opus 4

Claude Opus 4 vs Gemini 2.5 Flash benchmark

Interactive Comparison Diagram

Matchup Breakdown

Tug-of-War Matchup Matrix

Category wins across intelligence, speed, and pricing efficiency.

Claude Opus 4 (5)vsGemini 2.5 Flash (5)

Claude Opus 4: 5W (50%)Overall: Even matchupGemini 2.5 Flash: 5W (50%)

← Claude Opus 4Gemini 2.5 Flash →

Claude Opus 4 (5/5)

Intelligence & Reasoning

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

Preference Elo

1,490vs1,295

Coding Elo

1,502vs—

SWE-bench

72.5%vs48%

LiveBench

66.8%vs51.4%

GPQA Diamond

80.4%vs68.2%

Claude Opus 4: 5WGemini 2.5 Flash: 0W

Gemini 2.5 Flash (2/2)

Speed & Latency

Generation throughput and time to first token responsiveness

Output speed

58 tok/svs185 tok/s

Time to first token

390 msvs110 ms

Claude Opus 4: 0WGemini 2.5 Flash: 2W

Gemini 2.5 Flash (3/3)

Pricing & Capacity

Cost per million tokens and max context window length

Output price

$75/1Mvs$2.5/1M

Input price

$15/1Mvs$0.3/1M

Context window

200kvs1M

Claude Opus 4: 0WGemini 2.5 Flash: 3W

Recommended Workload Routing

Repo / coding agentsClaude Opus 4

Higher SWE-bench (72.5%).

High-volume chatGemini 2.5 Flash

Lower output list price ($2.5/1M).

Voice / low-latency UIGemini 2.5 Flash

Lower TTFT (110 ms).

Long-document RAGGemini 2.5 Flash

Larger window (1M).

Screenshots / visionClaude Opus 4

Both accept images. Defaulting to the higher-Elo side (Claude Opus 4).

Target Workload	Recommended Pick	Evaluation Rationale
Repo / coding agents	Claude Opus 4	Higher SWE-bench (72.5%).
High-volume chat	Gemini 2.5 Flash	Lower output list price ($2.5/1M).
Voice / low-latency UI	Gemini 2.5 Flash	Lower TTFT (110 ms).
Long-document RAG	Gemini 2.5 Flash	Larger window (1M).
Screenshots / vision	Claude Opus 4	Both accept images. Defaulting to the higher-Elo side (Claude Opus 4).

Frequently Asked Questions

Which is better overall, Claude Opus 4 or Gemini 2.5 Flash?

Claude Opus 4 has the higher preference Elo in our latest snapshot (1,490). “Better” still depends on coding, price, and latency — see the table.

Which is better at coding, Claude Opus 4 or Gemini 2.5 Flash?

Claude Opus 4 leads SWE-bench at 72.5% vs 48%. SWE-bench is one harness, not your repo.

Which is cheaper to run in production?

Gemini 2.5 Flash output tokens are $2.5/1M versus $75/1M. Input prices and retry rates still move the real bill.

Which is faster, Claude Opus 4 or Gemini 2.5 Flash?

Gemini 2.5 Flash has the lower time-to-first-token (110 ms vs 390 ms). Tokens/sec is a separate column if you care about long completions.

Which has the larger context window?

Gemini 2.5 Flash accepts 1M 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 Opus 4 and Gemini 2.5 Flash Elo cells are dated snapshots from the named source — we do not compute Arena ourselves.

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Interactive Comparison Diagram

Tug-of-War Matchup Matrix

Intelligence & Reasoning

Speed & Latency

Pricing & Capacity

Multi-Dimensional Capability Radar

Claude Opus 4

Gemini 2.5 Flash

Gemini 2.5 Flash

Full Benchmark Score Matrix

Workload Cost & Savings Calculator

Key Selection Recommendations

Recommended Workload Routing

Related Editorial Dispatches & Benchmark Notes

Gemini 2.5 Flash: previous Google speed workhorse, still a baseline

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Claude Opus 4

Gemini 2.5 Flash

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

Gemini 2.5 Flash

Gemini 2.5 Flash

Full Benchmark Score Matrix

Workload Cost & Savings Calculator

Key Selection Recommendations

Recommended Workload Routing

Related Editorial Dispatches & Benchmark Notes

Gemini 2.5 Flash: previous Google speed workhorse, still a baseline

Cast Your Matchup Vote

Community Discussions (0)

Share card

CompareLLM Matrix

Claude Opus 4

Gemini 2.5 Flash

Frequently Asked Questions

Related news

Similar Head-to-Head Comparisons