AnthropicUnited States· released Jun 2026

Claude Sonnet 5

Name: Claude Sonnet 5
Author: Anthropic

Ranked #17, 29.0% behind the frontier on average.

Anthropic, United States. One of 12 models from this lab on the Index.

Third-party publishedMedium confidence (7+ comparable tests, 3+ Index categories)

Available in Theo as Theo Think

Theo orchestrates it for the steps it does best and always shows which engine answered.

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Snapshot September 8, 2026

OpenCharts Index

71.0

Ranked #17 (12 to 18) of 36 · 29.0% behind the frontier on average · 17 comparable tests · 3 counting categories

Drop any single test and the Index lands between 68.0 and 75.2, anywhere from #12 to #18. Neighbours inside that range are ties.

Needs more results (2 of 8 so far)

Averaging 50.0 on the 2 it has; the score opens at 4 of 8.

Distance to today's frontier on the hardest tests. Not a measure of intelligence.

What it's known for

Claude Sonnet 5, in 17 results.

Strongest in reasoning (72.9) and coding (72.1). It trails the frontier most in math, 32.1% behind on average. No comparable result yet in long context. Between 25% and 30% behind the best published results, on average. Drop any single test and it would sit anywhere from #12 to #18.

Strongest category

Reasoning

Hard, novel problems: graduate science, abstract puzzles, expert exams.

72.9

GPQA Diamond90.5% · 93% of best
SimpleBench60.6% · 74% of best
CritPt16.9% · 52% of best

Mean of 3 of the category's 6 comparable tests. Counts toward the Index.

Best single result

Mock AIME 2024–2025

Solve competition mathematics problems that have a single exact integer answer.

94.7%

94.7% of the best (100.0%) · #24 of 78.

Olympiad-style problems need long, careful chains of reasoning, and there is no partial credit.

Where it trails

FrontierMath Tier 4

Solve the hardest FrontierMath tier: problems that take expert mathematicians days.

29.3%

70.0% behind the best published result (97.6%) · #22 of 51.

The deepest end of the set. Progress here signals genuinely new capability.

Not measured yet

No comparable result yet in this category. A blank is a blank, never a zero, and it does not lower the Index.

Long context

Covered, but not averaged into the Index:

Knowledgesingle-test category, shown beside the Index · 44.6
Agentic2 of 8 tests · needs 4 · mean 75.3
Multimodalsingle-test category, shown beside the Index · 87.0
Human preferencesingle-test category, shown beside the Index · 87.2

Every score, with its source

See it at work

What Claude Sonnet 5 was asked to do, and how it did.

Every test it has taken, by category, with the kind of task it faced, who produced the number and where the result landed against the best published one. The examples are original and illustrative, never items from the datasets themselves.

Human preference · mean 87.2 across 1 comparable test · a single-test category, shown beside the Index and never averaged into it

Text ArenaLeaderboard

Answer the same prompt as a rival model; real users vote blind on which answer they prefer.

1,462

44% expected win rate against the board leader (1,507)
#36 of 92

high · board 2026-09-02

Source: Arena

Every result is read against the best published one on its test: percent scores as a share of the best above chance, Arena ratings as the expected win rate against the board leader, open-ended values on a log scale. Sitting a harder exam never lowers a model. Every number links to the publisher that produced it.

Head to head

Claude Sonnet 5 against whoever you pick.

Choose a rival. Every counted test both have taken appears side by side as a share of the best published result on that test, with the category means above. A win is a higher share; a gap under 2 points is a tie, because one item on a 45-problem exam is 2.2 points and publishers' own standard errors are of that order.

Claude Sonnet 5

#17·Index 71.0B-

0 : 12

wins · 0 ties · 12 shared

GPT-6 Astra

#1·Index 99.0A+

GPT-6 Astra comes out ahead on 12 of the 12 tests both have taken.

Category means

Reasoning
72.9
99.6
Knowledge
44.6
100.0
Coding
72.1
97.7
Math
67.9
99.8
Agentic
75.3
98.5
Multimodal
87.0
—
Human preference
87.2
—

Shared tests · biggest gaps first

FrontierMath Tier 4Math
29.3%
97.6%
−70.0
Code Arena (WebDev)Coding
1,537
1,797
−63.4
SimpleQA VerifiedKnowledge
33.7%
75.6%
−55.4
CritPtReasoning
16.9%
31.7%
−46.0
FrontierMath (Tiers 1–3)Math
65.6%
93.7%
−30.0
APEX-AgentsAgentic
32.5%
46.7%
−29.9
WeirdMLCoding
68.8%
92.9%
−26.0
ProofBenchMath
77.0%
99.0%
−22.0
FrontierCodeCoding
42.7%
53.3%
−19.7
GPQA DiamondReasoning
90.5%
95.8%
−7.4
Mock AIME 2024–2025Math
94.7%
100.0%
−5.3
SciCodeCoding
53.6%
56.5%
−4.6

Bars are distances to the best published result on each test (percent scores above chance, Arena ratings as win rate against the leader, open-ended values on a log scale). Raw values as the publishers report them.

Open GPT-6 Astra

Scores

Every test, every source

The best published run per benchmark, the raw value as the publisher reports it, who produced the number, how close it comes to the best published result on that test, and where the model sits among every model scored on it. Percent scores are read above chance, Arena ratings as a win rate against the board leader, open-ended values on a log scale. A test with too few models to compare against is shown but not counted.

Category means

Reasoning72.9 · 3/6
Knowledgebeside44.6 · 1/1
Coding72.1 · 5/7
Math67.9 · 4/5
Agentic75.3 · 2/8
Multimodalbeside87.0 · 1/1
Human preferencebeside87.2 · 1/1
Long context—

Mean · tests taken of the category's comparable tests. A faded category either rests on fewer than half of them or is a single-test category (marked “beside”), which is shown next to the Index and never averaged into it.

GPQA DiamondEpoch-runReasoning

90.5%

92.6% of the best (95.8%), above chance
65th percentile of 78 · n = 198

xhigh

Source: Epoch AI — AI Benchmarking Hub

SimpleBenchLeaderboardReasoning

60.6%

74.0% of the best (81.9%)
49th percentile of 46

Source: Epoch AI — AI Benchmarking Hub

CritPtLeaderboardReasoning

16.9%

52.2% of the best (32.3%)
71th percentile of 78