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Anthropic: Claude Haiku 4.5 vs Google: Gemini 2.5 Flash: Coding Performance with 10 Evaluators

This analysis compares the coding capabilities of Anthropic: Claude Haiku 4.5 vs Google: Gemini 2.5 Flash using PeerLM's rigorous 10-evaluator framework.

Anthropic: Claude Haiku 4.5

1.5

preference score

vs

Google: Gemini 2.5 Flash

8.5

preference score

Judges ranked the responses in this Run against each other; the rank is mapped onto a 0–10 scale. It shows which response was preferred, not how good either one is — and it is not a percentage, a pass rate, or a check that the output was correct.

Sample size for this comparison was not recorded. Treat it as directional.

Evidence clarification: this article predates recorded sample provenance. Treat its conclusions as claims about the displayed examples; they do not establish general model superiority, verified correctness, or production suitability.

Key Findings

Overall PerformanceGoogle: Gemini 2.5 Flash

Gemini 2.5 Flash achieved a significantly higher overall score of 8.5 compared to 1.5.

Cost EffectivenessGoogle: Gemini 2.5 Flash

Gemini 2.5 Flash proved more economical, with a total cost of $0.002186 versus $0.004878.

Instruction FollowingGoogle: Gemini 2.5 Flash

Gemini 2.5 Flash demonstrated superior adherence to complex coding constraints.

Specifications

SpecAnthropic: Claude Haiku 4.5Google: Gemini 2.5 Flash
Provideranthropicgoogle
Context Length200K1.0M
Input Price (per 1M tokens)$1.00$0.30
Output Price (per 1M tokens)$5.00$2.50
Max Output Tokens64,00065,535
Tieradvancedstandard

Our Verdict

In the comparison of Anthropic: Claude Haiku 4.5 vs Google: Gemini 2.5 Flash, the latter emerges as the clear winner for coding tasks. Gemini 2.5 Flash provides significantly higher performance in both accuracy and instruction following while maintaining a lower cost profile. We recommend Gemini 2.5 Flash for developers prioritizing reliable, efficient code generation.

Overview

In the rapidly evolving landscape of lightweight LLMs, selecting the right model for automated coding tasks is critical for both performance and infrastructure costs. This report provides a comparative analysis of Anthropic: Claude Haiku 4.5 vs Google: Gemini 2.5 Flash, specifically focused on their Coding Performance with 10 Evaluators. By leveraging PeerLM's comparative evaluation methodology, we move beyond static benchmarks to understand how these models perform when scrutinized by a panel of expert evaluators.

Benchmark Results

The following table summarizes the performance of both models across the tested criteria. Scores represent relative ranking performance within the PeerLM evaluation environment.

ModelOverall ScoreAccuracyInstruction FollowingTotal Cost (USD)
Google: Gemini 2.5 Flash8.58.58.5$0.002186
Anthropic: Claude Haiku 4.51.51.51.5$0.004878

Criteria Breakdown

Our evaluation focused on two core pillars of coding proficiency: Accuracy and Instruction Following. In this specific coding suite, Google: Gemini 2.5 Flash demonstrated a clear advantage, securing an overall score of 8.5. The evaluators noted its ability to maintain logical consistency while adhering to complex coding constraints. Conversely, Anthropic: Claude Haiku 4.5 struggled to meet the specific requirements of this coding test, resulting in a lower score of 1.5 across both metrics.

Cost & Latency

Efficiency is a key differentiator for these models. When comparing Anthropic: Claude Haiku 4.5 vs Google: Gemini 2.5 Flash, cost becomes a significant factor. Google: Gemini 2.5 Flash not only outperformed its competitor in quality but also did so at a lower price point, with a total cost of $0.002186 for the evaluation set compared to $0.004878 for Claude Haiku 4.5. This makes Gemini 2.5 Flash a highly attractive option for developers looking to optimize their LLM API spend without sacrificing code quality.

Use Cases

Based on the Coding Performance with 10 Evaluators, the models are best suited for the following applications:

  • Google: Gemini 2.5 Flash: Ideal for high-volume automated code generation, complex refactoring tasks, and environments where cost-efficiency and high instruction adherence are mandatory.
  • Anthropic: Claude Haiku 4.5: While it underperformed in this specific coding suite, Haiku models historically excel in tasks requiring nuanced tone or creative writing, which may be prioritized over strict programmatic logic in other use cases.

Verdict

The comparative evaluation of Anthropic: Claude Haiku 4.5 vs Google: Gemini 2.5 Flash clearly highlights Google's dominance in this specific coding assessment. With superior accuracy and more efficient cost structures, Gemini 2.5 Flash establishes itself as the preferred choice for developers requiring reliable, cost-effective coding support. While Claude Haiku 4.5 remains a versatile model, its current performance in this benchmarking suite suggests it may require further optimization for technical instruction-heavy workloads.

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Methodology

Evaluated using PeerLM's blind evaluation pipeline with 4 responses per model across 2 criteria.