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HEAD TO HEAD · UPDATED NOV 6, 2026
Claude Fable 5.1 vs DeepSeek V4.1-Flash
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 Fable 5.1 | DeepSeek V4.1-Flash | |
|---|---|---|
| Arena Elo | 1504 source ↗ | 1476 source ↗ |
| GPQA Diamond | not published | 90.9% source ↗ |
| $ per 1M in / out | $10 / $50 source ↗ | $0.15 / $0.60 source ↗ |
| Blended $ per 1M (3:1) | $20.00 source ↗ | $0.26 source ↗ |
| Context window | 1M source ↗ | 1M source ↗ |
| Output speed | not published | 174 tok/s source ↗ |
| Released | Sep 1, 2026 source ↗ | Sep 10, 2026 source ↗ |
| Open weights | No source ↗ | Yes source ↗ |
| Reasoning effort tiers | low · medium · high · xhigh · max (default: high) | 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 | Terminal-Bench 4.0: 55.8% source ↗ GDPval-AA v2.1: 1735 source ↗ AA Intelligence Index v5.0.1: 50 source ↗ | DeepSWE v1.1: 77.0% (Oct 17 update; 74.2% on Sep 10) source ↗ |
| Best for (workload) | Anthropic's most capable generally available model, for demanding reasoning and long-horizon agentic work (Anthropic). source ↗ | Fastest output we track (174 tok/s, Artificial Analysis) and the lowest list price ($0.15 / $0.60 off-peak); 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 V4.1-Flash is about 76.2 times cheaper per token. For overall answer quality as rated by people in blind tests, Claude Fable 5.1 leads clearly (1504 vs 1476 Arena Elo). If you need to self-host or fine-tune, only DeepSeek V4.1-Flash 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 V4.1-Flash is the cheaper option: $0.26 vs $20.00 per 1M tokens at a 3:1 input-to-output mix (about 76.2 times less).
- Claude Fable 5.1 scores 28 Elo points higher (1504 vs 1476) on the Arena text leaderboard, where people vote on blind side-by-side answers.
- Claude Fable 5.1 pricing note: Same rate across the full 1M context window.
- DeepSeek V4.1-Flash pricing note: Off-peak price (cache hit $0.003 / 1M). Peak hours (01:00 to 04:00 and 06:00 to 10:00 UTC, weekdays): $0.30 / $1.20 (cache hit $0.006 / 1M).
Frequently asked questions
Is Claude Fable 5.1 or DeepSeek V4.1-Flash better?
DeepSeek V4.1-Flash is the cheaper option: $0.26 vs $20.00 per 1M tokens at a 3:1 input-to-output mix (about 76.2 times less). Claude Fable 5.1 scores 28 Elo points higher (1504 vs 1476) on the Arena text leaderboard, where people vote on blind side-by-side answers. Claude Fable 5.1 pricing note: Same rate across the full 1M context window. DeepSeek V4.1-Flash pricing note: Off-peak price (cache hit $0.003 / 1M). Peak hours (01:00 to 04:00 and 06:00 to 10:00 UTC, weekdays): $0.30 / $1.20 (cache hit $0.006 / 1M).
Which one should I use: Claude Fable 5.1 or DeepSeek V4.1-Flash?
For high-volume work where cost matters most, DeepSeek V4.1-Flash is about 76.2 times cheaper per token. For overall answer quality as rated by people in blind tests, Claude Fable 5.1 leads clearly (1504 vs 1476 Arena Elo). If you need to self-host or fine-tune, only DeepSeek V4.1-Flash 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 Fable 5.1 cost compared with DeepSeek V4.1-Flash?
Claude Fable 5.1 lists at $10 / $50 per 1M input/output tokens ($20.00/1M blended at 3:1). DeepSeek V4.1-Flash lists at $0.15 / $0.60 per 1M input/output tokens ($0.26/1M blended at 3:1).
Facts checked Nov 5, 2026 against official sources. Every number links to its source. Spotted an error? Email [email protected].