Standard Compute
Model comparison 2026

Claude Sonnet 5.5 vs DeepSeek R1 (0528)

Claude Sonnet 5.5
Anthropic · Balanced · Proprietary
$4.40/1M · 1M ctx
DeepSeek R1 (0528)
DeepSeek · Balanced · Open weights
$0.99/1M · 164K ctx

Community vote

Pick a winner in each dimension. You can change your vote any time.

Output Quality
Correctness and depth of what it produces
Agentic Ability
Tool calls, instruction-following, and multi-step tasks
Speed
Tokens per second and time-to-first-token
Value for money
How much capability you get per dollar
Reliability
Consistent results: fewer refusals, loops and format breaks

Specs and pricing side by side

Spec
Sonnet 5.5
DeepSeek R1
Maker
Anthropic
DeepSeek
Blended price / 1M
$4.40
$0.99
Input / output
$2.00 in · $10 out / 1M tokens
$0.50 in · $2.15 out / 1M tokens
Context window
1M
164K
Open weights
No
Yes
Tool use
Yes
Yes
Reasoning
Yes
Yes
Output Quality
9.8
7.5
Agentic Ability
9.8
7.0
Speed
8.4
6.8
Value for money
8.8
8.6
Reliability
9.4
8.6

Pricing and capabilities synced from the OpenRouter catalogue. Scores are editorial (0–10).

Verdict: Sonnet 5.5 or DeepSeek R1?

Updated 2026-10-13

Choose Claude Sonnet 5.5 if you want the everyday default for coding agents, escalating to Opus 5.5 only for the hardest tasks. Choose DeepSeek R1 (0528) if you want reasoning-heavy planning where cost matters.

In our editorial scoring, Claude Sonnet 5.5 leads in 5 of five dimensions (output quality, agentic ability, speed, value for money and reliability), while DeepSeek R1 (0528) leads in 0. On price, Claude Sonnet 5.5 runs about $4.40 per 1M tokens (blended) and is proprietary; DeepSeek R1 (0528) is about $0.99 and open-weight.

Where Sonnet 5.5 falls short
  • Artificial Analysis flags it as very verbose, which adds output tokens
  • Released September 2026, so its long-run track record is still short
Full Sonnet 5.5 breakdown →
Where DeepSeek R1 falls short
  • Slow due to long reasoning
  • Weaker at fast tool loops
Full DeepSeek R1 breakdown →

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