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HEAD TO HEAD · UPDATED NOV 6, 2026
Claude Opus 5.5 vs DeepSeek V4-Pro
Anthropic against DeepSeek, on sourced numbers only. Green marks the higher (or cheaper) value on each row; the text below only calls a lead when the gap is bigger than measurement noise.
| Claude Opus 5.5 | DeepSeek V4-Pro | |
|---|---|---|
| Arena Elo | 1509 source ↗ | 1465 source ↗ |
| GPQA Diamond | 90.6% source ↗ | 92.4% source ↗ |
| $ per 1M in / out | $4 / $20 source ↗ | $0.66 / $1.98 source ↗ |
| Blended $ per 1M (3:1) | $8.00 source ↗ | $0.99 source ↗ |
| Context window | 1M source ↗ | 1M source ↗ |
| Output speed | 110 tok/s source ↗ | not published |
| Released | Sep 22, 2026 source ↗ | Aug 13, 2026 source ↗ |
| Open weights | No source ↗ | Yes source ↗ |
| Reasoning effort tiers | low · medium · high · xhigh · max (default: medium) | low · high · max (default: high) |
| API effort control | output_config={"effort": "low" | "medium" | "high" | "xhigh" | "max"} source ↗ | thinking={"type": "enabled" | "disabled"}, reasoning_effort="low" | "high" | "max" (medium and xhigh map to high) source ↗ |
| Additional benchmarks | Arena WebDev: 1810 (#1) source ↗ SWE-bench Pro: 89.9% source ↗ Terminal-Bench 4.0: 66.4% (xhigh) source ↗ GDPval-AA v2.1: 1846 source ↗ CursorBench 4.0: 57.8% at max effort, 52.5% at default source ↗ AA Intelligence Index v5.0.1: 59 source ↗ | SWE-bench Verified: 80.6% (April V4 preview card, Max) source ↗ |
| Best for (workload) | Anthropic suggests starting with Opus 5.5 for most workloads. #1 on Arena WebDev (1810); 66.4% on Terminal-Bench 4.0 at xhigh effort (Anthropic). source ↗ | Higher GPQA Diamond than V4.1-Flash (92.4% vs 90.9%, DeepSeek); MIT open weights. source ↗ |
Arena Elo from the arena.ai text leaderboard as of Oct 27, 2026 source ↗. Speed measured by Artificial Analysis and varies by provider.
Which one should I use?
For high-volume work where cost matters most, DeepSeek V4-Pro is about 8.1 times cheaper per token. For overall answer quality as rated by people in blind tests, Claude Opus 5.5 leads clearly (1509 vs 1465 Arena Elo). If you need to self-host or fine-tune, only DeepSeek V4-Pro has open weights. On release timing, Anthropic is at day 30 of a typical ~15-day gap (PAST TYPICAL GAP), and DeepSeek is at day 20 of a typical ~32-day gap (MID-CYCLE).
Key differences from the sourced numbers
- DeepSeek V4-Pro is the cheaper option: $0.99 vs $8.00 per 1M tokens at a 3:1 input-to-output mix (about 8.1 times less).
- Claude Opus 5.5 scores 44 Elo points higher (1509 vs 1465) on the Arena text leaderboard, where people vote on blind side-by-side answers.
- On GPQA Diamond they are close (90.6% vs 92.4%).
- Claude Opus 5.5 pricing note: Same rate across the full 1M context window.
- DeepSeek V4-Pro pricing note: Off-peak price (cache hit $0.022 / 1M). Peak hours (01:00 to 04:00 and 06:00 to 10:00 UTC, weekdays): $1.32 / $3.96 (cache hit $0.044 / 1M). API continues until V4.1-Pro launches.
Frequently asked questions
Is Claude Opus 5.5 or DeepSeek V4-Pro better?
DeepSeek V4-Pro is the cheaper option: $0.99 vs $8.00 per 1M tokens at a 3:1 input-to-output mix (about 8.1 times less). Claude Opus 5.5 scores 44 Elo points higher (1509 vs 1465) on the Arena text leaderboard, where people vote on blind side-by-side answers. On GPQA Diamond they are close (90.6% vs 92.4%). Claude Opus 5.5 pricing note: Same rate across the full 1M context window. DeepSeek V4-Pro pricing note: Off-peak price (cache hit $0.022 / 1M). Peak hours (01:00 to 04:00 and 06:00 to 10:00 UTC, weekdays): $1.32 / $3.96 (cache hit $0.044 / 1M). API continues until V4.1-Pro launches.
Which one should I use: Claude Opus 5.5 or DeepSeek V4-Pro?
For high-volume work where cost matters most, DeepSeek V4-Pro is about 8.1 times cheaper per token. For overall answer quality as rated by people in blind tests, Claude Opus 5.5 leads clearly (1509 vs 1465 Arena Elo). If you need to self-host or fine-tune, only DeepSeek V4-Pro has open weights. On release timing, Anthropic is at day 30 of a typical ~15-day gap (PAST TYPICAL GAP), and DeepSeek is at day 20 of a typical ~32-day gap (MID-CYCLE).
How much does Claude Opus 5.5 cost compared with DeepSeek V4-Pro?
Claude Opus 5.5 lists at $4 / $20 per 1M input/output tokens ($8.00/1M blended at 3:1). DeepSeek V4-Pro lists at $0.66 / $1.98 per 1M input/output tokens ($0.99/1M blended at 3:1).
Facts checked Nov 5, 2026 against official sources. Every number links to its source. Spotted an error? Email [email protected].