Claude Sonnet 4.5 vs Step 3.7 Flash
Side-by-side benchmark comparison across coding, math, reasoning, speed, and pricing.
Step 3.7 Flash by StepFun wins on 5 of 9 benchmarks against Claude Sonnet 4.5 by Anthropic, which leads on 4. This head-to-head comparison covers coding, math, reasoning, speed, and pricing metrics from our benchmark data.
Category-by-Category Breakdown
Coding: In coding, Claude Sonnet 4.5 scores 52.1 on AA Coding Index compared to Step 3.7 Flash's 39.6, while Claude Sonnet 4.5 scores 1184 on Design Arena ELO compared to Step 3.7 Flash's 1172, while Step 3.7 Flash scores 1206 on Website Arena ELO compared to Claude Sonnet 4.5's 1202.
Reasoning: In reasoning, Claude Sonnet 4.5 scores 82.5% on GPQA Diamond compared to Step 3.7 Flash's 76.6%, while Step 3.7 Flash scores 77.3% on τ²-Bench Airline compared to Claude Sonnet 4.5's 73.0%.
Context: In context, Claude Sonnet 4.5 scores 1.0M on Context Length compared to Step 3.7 Flash's 262K.
Pricing Comparison
Claude Sonnet 4.5 costs $3.0/1M input tokens and $15.0/1M output tokens, while Step 3.7 Flash costs $0.20/1M input and $1.1/1M output. Step 3.7 Flash is the more affordable option for API usage.
Verdict
Step 3.7 Flash leads across the board in affordability, making it the stronger overall choice in this comparison.
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Claude Sonnet 4.5 vs Step 3.7 Flash — FAQ
Which is better, Claude Sonnet 4.5 or Step 3.7 Flash?
Step 3.7 Flash wins on more benchmarks overall (5 vs 4). However, the best choice depends on your specific needs — each model excels in different areas.
How does Claude Sonnet 4.5 compare to Step 3.7 Flash for coding?
SWE-bench Verified data is not available for both models. Check the detailed comparison charts above for other coding-related metrics.
Is Claude Sonnet 4.5 cheaper than Step 3.7 Flash?
Yes, Step 3.7 Flash is cheaper. Claude Sonnet 4.5 costs $3.0/1M input and $15.0/1M output tokens. Step 3.7 Flash costs $0.20/1M input and $1.1/1M output tokens.
Which is faster, Claude Sonnet 4.5 or Step 3.7 Flash?
Output speed data is not available for both models. Check the speed section of the comparison above for available performance data.
What benchmarks does the Claude Sonnet 4.5 vs Step 3.7 Flash comparison cover?
This comparison covers 9 benchmarks including GPQA Diamond, Input Cost, Output Cost, Context Length, AA Coding Index, Cached Input Cost, Design Arena ELO, τ²-Bench Airline, and more. Metrics span general intelligence, coding, math, reasoning, speed, and cost categories.