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Model comparison

Claude Mythos 5 vs GPT-4.1 nano

Data verified

Head-to-head evidence from 1 shared benchmark result across 1 category. Overall scores shown here use the public BenchAlign v5 ranking lane.

83.93/100
Margin
41.9pts
← winning
42.06/100
2 category wins0 category wins

Public leaderboard positions: Claude Mythos 5 #1 (Supported); GPT-4.1 nano #161 (Estimated). Intervals and evidence labels describe ranking uncertainty, not a guarantee for a specific workload.

Evidence parity. Claude Mythos 5 and GPT-4.1 nano share 1 comparable benchmark result. 2 of 8 categories are comparable. 14 results are unique to Claude Mythos 5; 20 to GPT-4.1 nano.

Updated July 23, 2026
Shared results
1
Claude Mythos 5 only
14
GPT-4.1 nano only
20
Comparable categories
2 / 8

Pick Claude Mythos 5 if you want the stronger benchmark profile. GPT-4.1 nano only becomes the better choice if you want the cheaper token bill or you would rather avoid the extra latency and token burn of a reasoning model.

Confidence note. This is a partial-evidence comparison with 1 shared benchmark result across 1 evidence category; 2 of 8 categories currently have scoreable aggregates for both models. Treat the verdict as directional until coverage is more balanced.

Why this result

Claude Mythos 5 is clearly ahead on the BenchAlign aggregate, 83.93 to 42.06. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.

Claude Mythos 5's sharpest advantage is in mathematics, where it averages 97.6 against 1. The single biggest benchmark swing on the page is GPQA, 94.1% to 50.3%.

Claude Mythos 5 is also the more expensive model on tokens at $10.00 input / $50.00 output per 1M tokens, versus $0.10 input / $0.40 output per 1M tokens for GPT-4.1 nano. That is roughly 125.0x on output cost alone. Claude Mythos 5 is the reasoning model in the pair, while GPT-4.1 nano is not. That usually helps on harder chain-of-thought-heavy tests, but it can also mean more latency and more token spend in real use. Claude Mythos 5 gives you the larger context window at 1M+, compared with 1M for GPT-4.1 nano.

Category breakdown

Exact category averages are shown below. Not measured means BenchLM does not have enough sourced public coverage for that model and category.

Category scores and score margins for Claude Mythos 5 and GPT-4.1 nano
CategoryClaude Mythos 5ΔGPT-4.1 nano
MathClaude Mythos 597.6Margin← 96.6GPT-4.1 nano1.0
KnowledgeClaude Mythos 568.5Margin← 18.2GPT-4.1 nano50.3
AgenticClaude Mythos 587.0MarginNo overlapGPT-4.1 nanoNot measured
CodingClaude Mythos 589.7MarginNo overlapGPT-4.1 nanoNot measured
MultimodalClaude Mythos 593.5MarginNo overlapGPT-4.1 nanoNot measured
Inst. FollowingClaude Mythos 5Not measuredMarginNo overlapGPT-4.1 nano83.2

Decisive benchmark drivers

The largest measured benchmark gaps in this matchup, with exact reported values.

More
A · Claude Mythos 5B · GPT-4.1 nano

  1. GPQA

    Knowledge
    Source ↗
    A 94.1%B 50.3%
    Winner: Claude Mythos 5Δ 43.8
    GPQA: Claude Mythos 5 scored 94.1%; GPT-4.1 nano scored 50.3%. Claude Mythos 5 wins this benchmark.

Operational comparison

Runtime and commercial metrics are compared only when both models have a complete sourced value.

MetricClaude Mythos 5GPT-4.1 nanoComparison
Input / output priceUSD per 1M tokensClaude Mythos 5$10 input / $50 outputGPT-4.1 nano$0.1 input / $0.4 outputGPT-4.1 nano has the lower combined listed price.
Generation speedtokens per secondClaude Mythos 5Not availableGPT-4.1 nano181 tok/sA complete speed comparison is not available.
First-answer latencyseconds to first tokenClaude Mythos 5Not availableGPT-4.1 nano0.63 sA complete latency comparison is not available.
Context windowmaximum listed tokensClaude Mythos 51M+GPT-4.1 nano1MClaude Mythos 5 lists the larger context window.

Benchmark Deep Dive

Agentic
BenchmarkClaude Mythos 5GPT-4.1 nanoResult
Terminal-Bench 2.0Source 88%—Not comparable
OSWorld-VerifiedSource 85%—Not comparable
BrowseCompSource 88%—Not comparable
ExploitGymSource 17.5%—Not comparable
AA Agentic IndexSource —1.2%Not comparable
τ²-bench resultsSource —17.3%Not comparable
GDPval-AASource —0.0%Not comparable
GDPval-AASource —41Not comparable
Coding
BenchmarkClaude Mythos 5GPT-4.1 nanoResult
SWE-bench VerifiedSource 95.5%—Not comparable
SWE-bench ProSource 80.3%—Not comparable
Terminal-Bench 2.0Source 88.0%—Not comparable
AA Coding IndexSource —11.1%Not comparable
AA-SciCodeSource —25.9%Not comparable
Reasoning
BenchmarkClaude Mythos 5GPT-4.1 nanoResult
AA-LCRSource —17.0%Not comparable
CritPtSource —0.0%Not comparable
KnowledgeClaude Mythos 5 wins
BenchmarkClaude Mythos 5GPT-4.1 nanoResult
GPQASource 94.1%50.3%Claude Mythos 5 leads
HLESource 64.5%—Not comparable
HLE w/o toolsSource 59%—Not comparable
MMLUSource —80.1%Not comparable
Artificial Analysis Intelligence IndexSource —9.6%Not comparable
AA-GPQA DiamondSource —51.2%Not comparable
AA-HLESource —3.9%Not comparable
AA-Omniscience IndexSource —-56.4%Not comparable
AA-Omniscience AccuracySource —13.3%Not comparable
AA-Omniscience Hallucination RateSource —80.4%Not comparable
MathClaude Mythos 5 wins
BenchmarkClaude Mythos 5GPT-4.1 nanoResult
USAMO 2026Source 97.6%—Not comparable
FrontierMath v2 (Tiers 1-3)Source —1.034%Not comparable
Multilingual
BenchmarkClaude Mythos 5GPT-4.1 nanoResult
SWE MultilingualSource 92.2%—Not comparable
Multimodal
BenchmarkClaude Mythos 5GPT-4.1 nanoResult
SWE-bench MultimodalSource 54.9%—Not comparable
CharXivSource 93.5%—Not comparable
CharXiv w/o toolsSource 88.9%—Not comparable
AA-MMMU-ProSource —40.1%Not comparable
Design Arena WebsiteSource —1003Not comparable
Inst. Following
BenchmarkClaude Mythos 5GPT-4.1 nanoResult
IFEvalSource —83.2%Not comparable
AA-IFBenchSource —32.0%Not comparable
Frequently Asked Questions (3)

Which is better, Claude Mythos 5 or GPT-4.1 nano?

Claude Mythos 5 is ahead on BenchLM's BenchAlign leaderboard, 83.93 to 42.06. The biggest single separator in this matchup is GPQA, where the scores are 94.1% and 50.3%.

Which is better for knowledge tasks, Claude Mythos 5 or GPT-4.1 nano?

Claude Mythos 5 has the edge for knowledge tasks in this comparison, averaging 68.5 versus 50.3. Inside this category, GPQA is the benchmark that creates the most daylight between them.

Which is better for math, Claude Mythos 5 or GPT-4.1 nano?

Claude Mythos 5 has the edge for math in this comparison, averaging 97.6 versus 1. GPT-4.1 nano stays close enough that the answer can still flip depending on your workload.

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