Model comparison
Claude Sonnet 4.5 Thinking vs DeepSeek V4 Flash
Head-to-head evidence from 1 shared benchmark result across 1 category. Overall scores shown here use the public BenchAlign v5 ranking lane.
Public leaderboard positions: Claude Sonnet 4.5 Thinking unranked (Not scored); DeepSeek V4 Flash #61 (Estimated). Intervals and evidence labels describe ranking uncertainty, not a guarantee for a specific workload.
Evidence parity. Claude Sonnet 4.5 Thinking and DeepSeek V4 Flash share 1 comparable benchmark result. 0 of 8 categories are comparable. 1 result is unique to Claude Sonnet 4.5 Thinking; 21 to DeepSeek V4 Flash.
Updated July 23, 2026- Shared results
- 1
- Claude Sonnet 4.5 Thinking only
- 1
- DeepSeek V4 Flash only
- 21
- Comparable categories
- 0 / 8
Benchmark data for Claude Sonnet 4.5 Thinking and DeepSeek V4 Flash is coming soon on BenchLM.
Confidence note. This is a partial-evidence comparison with 1 shared benchmark result across 1 evidence category; 0 of 8 categories currently have scoreable aggregates for both models. Treat the verdict as directional until coverage is more balanced.
Why this result
BenchLM has partial data for these models, but not enough overlapping benchmark coverage to produce a fair score-level comparison yet.
DeepSeek V4 Flash has the larger context window at 1M, compared with 200K for Claude Sonnet 4.5 Thinking.
Category breakdown
Exact category averages are shown below. Not measured means BenchLM does not have enough sourced public coverage for that model and category.
| Category | Claude Sonnet 4.5 Thinking | Δ | DeepSeek V4 Flash |
|---|---|---|---|
| Agentic | Claude Sonnet 4.5 ThinkingNot measured | MarginNo overlap | DeepSeek V4 Flash49.1 |
| Coding | Claude Sonnet 4.5 ThinkingNot measured | MarginNo overlap | DeepSeek V4 Flash64.2 |
| Knowledge | Claude Sonnet 4.5 ThinkingNot measured | MarginNo overlap | DeepSeek V4 Flash38.8 |
| Math | Claude Sonnet 4.5 ThinkingNot measured | MarginNo overlap | DeepSeek V4 Flash40.8 |
Operational comparison
Runtime and commercial metrics are compared only when both models have a complete sourced value.
| Metric | Claude Sonnet 4.5 Thinking | DeepSeek V4 Flash | Comparison |
|---|---|---|---|
| Input / output priceUSD per 1M tokens | Claude Sonnet 4.5 ThinkingNot available | DeepSeek V4 Flash$0.14 input / $0.28 output | A complete price comparison is not available. |
| Generation speedtokens per second | Claude Sonnet 4.5 ThinkingNot available | DeepSeek V4 FlashNot available | A complete speed comparison is not available. |
| First-answer latencyseconds to first token | Claude Sonnet 4.5 ThinkingNot available | DeepSeek V4 FlashNot available | A complete latency comparison is not available. |
| Context windowmaximum listed tokens | Claude Sonnet 4.5 Thinking200K | DeepSeek V4 Flash1M | DeepSeek V4 Flash lists the larger context window. |
Benchmark Deep Dive
Agentic5 benchmarks
Coding5 benchmarks
Reasoning2 benchmarks
Knowledge6 benchmarks
Math4 benchmarks
Multimodal1 benchmarks
| Benchmark | Claude Sonnet 4.5 Thinking | DeepSeek V4 Flash | Result |
|---|---|---|---|
| Design Arena WebsiteSource | 1219 | 1238 | DeepSeek V4 Flash leads |
Frequently Asked Questions (3)
Can I compare Claude Sonnet 4.5 Thinking and DeepSeek V4 Flash on BenchLM yet?
Not fully yet. BenchLM is tracking both models, but the sourced benchmark breakdown for this comparison is still coming soon.
Why does this comparison show “coming soon”?
BenchLM only shows category winners and benchmark-level calls when we have sourced results that can be compared fairly. For these models, the public benchmark coverage is not complete enough yet.
What data is available for Claude Sonnet 4.5 Thinking and DeepSeek V4 Flash today?
DeepSeek V4 Flash: $0.14 input / $0.28 output per 1M tokens Both model pages still include creator, context window, reasoning mode, and other metadata while benchmark coverage fills in.
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