LLM Reference

Claude Sonnet 4.5 vs DeepSeek V4 Pro

Claude Sonnet 4.5 (2025) and DeepSeek V4 Pro (2026) are frontier-tier reasoning models from Anthropic and DeepSeek. Claude Sonnet 4.5 ships a 200k-token context window, while DeepSeek V4 Pro ships a 1m-token context window. On MMLU PRO, DeepSeek V4 Pro leads by 1.5 pts. This comparison covers specs, pricing, API access, capabilities, benchmarks, input and output token costs, and production fit for coding and agent workloads.

DeepSeek V4 Pro fits 5x more tokens; pick it for long-context work and Claude Sonnet 4.5 for tighter calls.

Decision scorecard

Local evidence first
SignalClaude Sonnet 4.5DeepSeek V4 Pro
Best forreasoning-heavy apps, multimodal apps, and tool-calling agentsreasoning-heavy apps, tool-calling agents, and long-context analysis
Decision fitCoding, RAG, and AgentsCoding, RAG, and Agents
Context window200k1m
Cheapest output$15/1M tokens$0.87/1M tokens
Provider routes8 tracked5 tracked
Shared benchmarks3 sharedMMLU PRO leader

Decision tradeoffs

Choose Claude Sonnet 4.5 when...
  • Claude Sonnet 4.5 has broader tracked provider coverage for fallback and route flexibility.
  • Claude Sonnet 4.5 uniquely exposes Vision and Multimodal in local model data.
  • Local decision data tags Claude Sonnet 4.5 for Coding, RAG, and Agents.
Choose DeepSeek V4 Pro when...
  • DeepSeek V4 Pro holds a shared-benchmark lead on MMLU PRO, ahead by 1.5 points.
  • DeepSeek V4 Pro has the larger context window for long prompts, retrieval packs, or transcript analysis.
  • DeepSeek V4 Pro has the lower cheapest tracked output price at $0.87/1M tokens.
  • Local decision data tags DeepSeek V4 Pro for Coding, RAG, and Agents.

Monthly cost at traffic

Estimate token spend from the cheapest tracked input and output route or tier on this page.

Lower estimate DeepSeek V4 Pro

Claude Sonnet 4.5

$6,150

Cheapest tracked route/tier: Microsoft Foundry

DeepSeek V4 Pro

$566

Cheapest tracked route/tier: DeepSeek Platform

Estimated monthly gap: $5,585. Batch, cache, alternate speed tiers, and negotiated pricing are excluded from this local estimate.

Switch friction

Claude Sonnet 4.5 -> DeepSeek V4 Pro
  • Provider overlap exists on OpenRouter and Vercel AI Gateway; start route-level A/B tests there.
  • DeepSeek V4 Pro is $14.13/1M tokens lower on cheapest tracked output pricing before cache, batch, or negotiated discounts.
  • Check replacement coverage for Vision and Multimodal before moving production traffic.
DeepSeek V4 Pro -> Claude Sonnet 4.5
  • Provider overlap exists on OpenRouter and Vercel AI Gateway; start route-level A/B tests there.
  • Claude Sonnet 4.5 is $14.13/1M tokens higher on cheapest tracked output pricing, so quality gains need to justify the spend.
  • Claude Sonnet 4.5 adds Vision and Multimodal in local capability data.

Specs

Specification
Released2025-09-292026-04-24
Context window200k1m
Parameters1.6T
ArchitectureDecoder OnlyMixture of Experts
LicenseProprietaryMITOSI-approved
OpennessProprietaryOpen source
WeightsNot releasedAvailable
CodeUnknownUnknown
Commercial useCommercial use: conditionalCommercial use: permitted
Knowledge cutoff2025-12-

Pricing and availability

Pricing attributeClaude Sonnet 4.5DeepSeek V4 Pro
Input price
0-200,001t
$3/1M tokens
200,001t+
$6/1M tokens
$0.43/1M tokens
Output price
0-200,001t
$15/1M tokens
200,001t+
$22.50/1M tokens
$0.87/1M tokens
Providers

Capabilities

CapabilityClaude Sonnet 4.5DeepSeek V4 Pro
VisionYesNo
MultimodalYesNo
ReasoningYesYes
JSON / Tool useYesYes
Structured outputsYesYes
Code executionNoNo
IDE integrationNoNo
Computer useNoNo
Parallel agentsNoNo

Benchmarks

BenchmarkClaude Sonnet 4.5DeepSeek V4 Pro
MMLU PRO86.087.5
SWE-bench Verified77.280.6
Google-Proof Q&A83.490.1

Continue comparing

Last reviewed: 2026-07-26. Data sourced from public model cards and provider documentation.