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Model Pareto

Claude Fable 5.1 vs Claude Sonnet 5.5

Claude Fable 5.1 scores higher in hard reasoning; Claude Sonnet 5.5 in coding. Claude Fable 5.1 costs 5× as much as Claude Sonnet 5.5 ($20.0 vs $4.00 per million tokens, blended 3:1 input:output).
Claude Fable 5.1Claude Sonnet 5.5
Focus

Coding: quality vs price

Compared models are ringed; the other 101 ranked here are greyed.

Lower price is better. Pareto frontier: Granite 4.2 3B, NVIDIA Nemotron 3 Nano 30B A3B, gpt-oss-20b, Ling-3.0-flash-VL, MiMo-V2.6-Flash, GLM-5.3 Flash, DeepSeek V4.1 Flash, MiMo-V2.6-Pro, Claude Sonnet 5.5, Claude Opus 5.5. 26 models are not plotted: Xing4.0-29B-A4B, Nex-N2.5-Pro, Atria Dawn Preview, Intern-S2-397B, Solar Open2 250B, Phi-4-reasoning-plus, Motif 3, Nex-N2-Pro, Nex-N2.5-Mini, A.X-K2, K2 Horizon 375B A23B, K-EXAONE 2.0 0803, K2 Horizon MoVA 36B A4B, Intern-S2-Preview (35B-A3B), Command A+, North Mini Code, G9v3-39A5B, Falcon-H1-34B-Instruct, Devstral 2, K2 Horizon 7B, Devstral Small 2, MiniCPM5-2B, Ling 3.0 Tiny, K2 Horizon 3.7B, K2 Horizon 0.9B, LFM2.5-2.6B.

26 models with no price data — shown in the strip at the left edge

Xing4.0-29B-A4B, Nex-N2.5-Pro, Atria Dawn Preview, Intern-S2-397B, Solar Open2 250B, Phi-4-reasoning-plus, Motif 3, Nex-N2-Pro, Nex-N2.5-Mini, A.X-K2, K2 Horizon 375B A23B, K-EXAONE 2.0 0803, K2 Horizon MoVA 36B A4B, Intern-S2-Preview (35B-A3B), Command A+, North Mini Code, G9v3-39A5B, Falcon-H1-34B-Instruct, Devstral 2, K2 Horizon 7B, Devstral Small 2, MiniCPM5-2B, Ling 3.0 Tiny, K2 Horizon 3.7B, K2 Horizon 0.9B, LFM2.5-2.6B

  • Best-value frontier (nothing is both cheaper and better)
  • Evidencestrong → weak
  • Estimated from other categories
  • Claude Fable 5.1
    Quality
    87.5
    Rank
    #3/103
    Price
    $20.0/M tok
    Speed
    66tok/s
    In$10Out$50/M tok

    vs Claude Sonnet 5.5: −4.1 quality · 5× price

  • Claude Sonnet 5.5
    Quality
    91.7
    Rank
    #2/103
    Price
    $4.00/M tok
    Speed
    —
    In$2.00▾Out$10▾/M tok

    vs Claude Fable 5.1: +4.1 quality · 0.2× price

Overview

Metric
Claude Fable 5.1
Claude Sonnet 5.5
Lab
Anthropic
Anthropic
Released
Sep 1, 2026
Sep 28, 2026
Weights
Proprietary
Proprietary
Input price
$/M tok
$10
$2.00Best
Output price
$/M tok
$50
$10Best
Blended price
$/M tok · 3:1 in:out
$20
$4.00Best
Output speed
tok/s
66
—
Context
tokens
1MBest
1MBest

Quality by category

0–100 within each category (100 = best tracked model). Rank is among all models ranked there. Click a row to focus it.

Metric
Claude Fable 5.1
Claude Sonnet 5.5
Coding
87.6±3.7
#3/103Mixed
91.7±5.2Best
#2/103Mixedbest value
Writing & chat
97.6±3.5
#1/146Verifiedbest value
Not ranked
Vision
87.4±7.3
#3/82Verified
Not ranked
Hard reasoning
95.7±3.7Best
#2/182Verified
95.2±4.9
#3/182Verifiedbest value
Agents
89.6±5.8
#2/173Verified
Not ranked

Coding benchmarks

Rank among models with a published score, and the leaderboard around each model. ~ italic = no published score, estimated from related benchmarks.

Metric
Claude Fable 5.1
Claude Sonnet 5.5
SWE-bench Verified
day 0
~#2/14~93.5%Estimated
  1. #1Claude Opus 596.0%
  2. ~#2Claude Fable 5.1Estimated93.5%
  3. #2Claude Sonnet 585.2%
estimated from related benchmarks
~#2/14~93.8%Estimated
  1. #1Claude Opus 596.0%
  2. ~#2Claude Sonnet 5.5Estimated93.8%
  3. #2Claude Sonnet 585.2%
estimated from related benchmarks
SWE-bench Pro (Public)
day 0
#3/1881.2%Lab-reported
  1. #1Claude Opus 5.589.9%
  2. #2Claude Sonnet 5.581.3%
  3. #3Claude Fable 5.181.2%
  4. #4Claude Opus 579.2%
anthropic.com · 2026-09-01
#2/1881.3%BestLab-reported
  1. #1Claude Opus 5.589.9%
  2. #2Claude Sonnet 5.581.3%
  3. #3Claude Fable 5.181.2%
anthropic.com · 2026-09-28
DeepSWE v1.1
day 0
#16/3064.3%Verified
  1. #1DeepSeek V4.1 Flash74.2%
  2. #15Grok 4.664.9%
  3. #16Claude Fable 5.164.3%
  4. #16Hy4 preview64.3%
artificialanalysis.ai · 2026-09-24
#5/3071.0%BestLab-reported
  1. #1DeepSeek V4.1 Flash74.2%
  2. #4Muse Spark 1.371.7%
  3. #5Claude Sonnet 5.571.0%
  4. #6GPT-5.6 Terra69.6%
anthropic.com · 2026-09-28
Terminal-Bench 4.0
day 0
#4/8352.0%Verified
  1. #1Claude Sonnet 5.563.6%
  2. #3GPT-6 Astra59.1%
  3. #4Claude Fable 5.152.0%
  4. #5Claude Opus 549.0%
artificialanalysis.ai · 2026-09-24
#1/8363.6%BestVerified
  1. #1Claude Sonnet 5.563.6%
  2. #2Claude Opus 5.559.6%
artificialanalysis.ai · 2026-09-28
LiveCodeBench
third-party
~#2/20~92.2%Estimated
  1. #1Qwen3.8-Omni-Flash92.6%
  2. ~#2Claude Fable 5.1Estimated92.2%
  3. #2Qwen3.8 Flash-Next91.9%
estimated from related benchmarks
~#2/20~92.2%Estimated
  1. #1Qwen3.8-Omni-Flash92.6%
  2. ~#2Claude Sonnet 5.5Estimated92.2%
  3. #2Qwen3.8 Flash-Next91.9%
estimated from related benchmarks
SciCode
third-party
#2/9563.1%BestVerified
  1. #1Claude Opus 5.566.9%
  2. #2Claude Fable 5.163.1%
  3. #3Claude Sonnet 5.561.0%
artificialanalysis.ai · 2026-09-24
#3/9561.0%Verified
  1. #1Claude Opus 5.566.9%
  2. #2Claude Fable 5.163.1%
  3. #3Claude Sonnet 5.561.0%
  4. #4MiMo-V2.6-Pro60.9%
artificialanalysis.ai · 2026-09-28
AA Coding Agent Index
third-party
#2/1462.2Verified
  1. #1Claude Opus 5.566.0
  2. #2Claude Fable 5.162.2
  3. #3GPT-6 Astra61.6
artificialanalysis.ai · 2026-09-24
~#4/15~61.0Estimated
  1. #1Claude Opus 5.566.0
  2. #3GPT-6 Astra61.6
  3. ~#4Claude Sonnet 5.5Estimated61.0
  4. #4Claude Opus 559.7
estimated from related benchmarks
Benchmarks in other categories (4)

Writing & chat benchmarks

Rank among models with a published score, and the leaderboard around each model. ~ italic = no published score, estimated from related benchmarks.

Metric
Claude Fable 5.1
Claude Sonnet 5.5

Vision benchmarks

Rank among models with a published score, and the leaderboard around each model. ~ italic = no published score, estimated from related benchmarks.

Metric
Claude Fable 5.1
Claude Sonnet 5.5
MMMU
day 0
~#2/3~71.3%Estimated
  1. #1Claude Haiku 4.573.2%
  2. ~#2Claude Fable 5.1Estimated71.3%
  3. #2Llama 4 Maverick69.4%
estimated from related benchmarks
—
MMMU-Pro
day 0
~#2/77~87.3%Estimated
  1. #1Claude Opus 5.587.7%
  2. ~#2Claude Fable 5.1Estimated87.3%
  3. #2GPT-6 Astra86.9%
estimated from related benchmarks
—
CharXiv Reasoning
day 0
~#2/9~86.0%Estimated
  1. #1Gemini 3.8 Flash86.2%
  2. ~#2Claude Fable 5.1Estimated86.0%
  3. #2Kimi K384.8%
estimated from related benchmarks
—
OmniDocBench v1.5
third-party
~#2/8~91.2%Estimated
  1. #1MiniMax-M391.6%
  2. ~#2Claude Fable 5.1Estimated91.2%
  3. #2Kimi K391.1%
estimated from related benchmarks
—
GDP.pdf (AA)
third-party
#3/4226.2%Verified
  1. #1GPT-6 Astra31.0%
  2. #2Muse Spark 1.326.6%
  3. #3Claude Fable 5.126.2%
  4. #3Claude Opus 5.526.2%
artificialanalysis.ai · 2026-09-24
—
Chartography
third-party
#4/2246.2%Verified
  1. #1GPT-6 Astra71.0%
  2. #3GPT-6 Sol53.6%
  3. #4Claude Fable 5.146.2%
  4. #5Gemini 3.8 Flash40.9%
surgehq.ai · 2026-09-24
—

Hard reasoning benchmarks

Rank among models with a published score, and the leaderboard around each model. ~ italic = no published score, estimated from related benchmarks.

Metric
Claude Fable 5.1
Claude Sonnet 5.5
GPQA Diamond
day 0
#4/17293.7%Verified
  1. #1GPT-6 Astra96.1%
  2. #3Gemini 3.1 Pro94.1%
  3. #4Claude Fable 5.193.7%
  4. #5GPT-5.593.5%
artificialanalysis.ai · 2026-09-24
~#2/173~96.0%Estimated
  1. #1GPT-6 Astra96.1%
  2. ~#2Claude Sonnet 5.5Estimated96.0%
  3. #2Gemini 3.8 Flash95.3%
estimated from related benchmarks
Humanity's Last Exam
day 0
#2/17859.1%BestVerified
  1. #1Claude Opus 5.561.4%
  2. #2Claude Fable 5.159.1%
  3. #3Claude Sonnet 5.555.0%
artificialanalysis.ai · 2026-09-24
#3/17855.0%Verified
  1. #1Claude Opus 5.561.4%
  2. #2Claude Fable 5.159.1%
  3. #3Claude Sonnet 5.555.0%
  4. #4Claude Opus 554.9%
artificialanalysis.ai · 2026-09-28
AIME (latest)
day 0
~#2/25~96.9%Estimated
  1. #1Inkling97.1%
  2. ~#2Claude Fable 5.1Estimated96.9%
  3. #2Muse Glimmer94.7%
estimated from related benchmarks
~#2/25~96.5%Estimated
  1. #1Inkling97.1%
  2. ~#2Claude Sonnet 5.5Estimated96.5%
  3. #2Muse Glimmer94.7%
estimated from related benchmarks
AA Intelligence Index
third-party
#3/7453.4Verified
  1. #1Claude Opus 5.557.6
  2. #2Claude Sonnet 5.556.0
  3. #3Claude Fable 5.153.4
  4. #4GPT-6 Astra52.7
artificialanalysis.ai · 2026-09-24
#2/7456.0BestVerified
  1. #1Claude Opus 5.557.6
  2. #2Claude Sonnet 5.556.0
  3. #3Claude Fable 5.153.4
artificialanalysis.ai · 2026-09-28

Agents benchmarks

Rank among models with a published score, and the leaderboard around each model. ~ italic = no published score, estimated from related benchmarks.

Metric
Claude Fable 5.1
Claude Sonnet 5.5
τ²-bench (Telecom)
day 0
~#2/116~98.3%Estimated
  1. #1Step 3.7 Flash98.5%
  2. ~#2Claude Fable 5.1Estimated98.3%
  3. #2Gemini 3.1 Pro95.6%
estimated from related benchmarks
—
OSWorld-Verified
day 0
~#2/12~84.6%Estimated
  1. #1Kimi K384.8%
  2. ~#2Claude Fable 5.1Estimated84.6%
  3. #2Qwen3.8 27B84.3%
estimated from related benchmarks
—
OSWorld 2.0
day 0
~#3/5~58.0%Estimated
  1. #1GLM-5.3 Flash59.1%
  2. #2Kimi K358.3%
  3. ~#3Claude Fable 5.1Estimated58.0%
  4. #3GPT-5.6 Terra50.2%
estimated from related benchmarks
—
BrowseComp
day 0
~#2/18~92.2%Estimated
  1. #1Atria Dawn Preview92.5%
  2. ~#2Claude Fable 5.1Estimated92.2%
  3. #2GPT-6 Astra91.5%
estimated from related benchmarks
—
GDPval-AA (Elo)
third-party
#2/861735Verified
  1. #1Claude Opus 5.51846
  2. #2Claude Fable 5.11735
  3. #3Claude Opus 51708
artificialanalysis.ai · 2026-09-24
—
AutomationBench-AA
third-party
#11/7959.4%Verified
  1. #1Claude Opus 5.569.5%
  2. #10GPT-5.6 Terra59.6%
  3. #11Claude Fable 5.159.4%
  4. #12MiMo-V2.6-Pro58.6%
artificialanalysis.ai · 2026-09-24
—
τ-Bench Banking (AA)
third-party
#6/8847.2%Verified
  1. #1Muse Spark 1.350.5%
  2. #5Qwen3.8 Max (0902)47.8%
  3. #6Claude Fable 5.147.2%
  4. #6GLM-5.3 Flash47.2%
artificialanalysis.ai · 2026-09-24
—
Not comparable across labs (1)
OSWorld 2.0 (Sept 2026 release)
day 0
#2/380.7%Lab-reported
  1. #1Claude Opus 5.581.8%
  2. #2Claude Fable 5.180.7%
  3. #3Claude Opus 574.0%
anthropic.com · 2026-09-22
—