Claude Opus 4.5 vs DeepSeek-V4-Flash
Wins 2 of 7 areas
Coding · Facts
Wins 5 of 7 areas
Agents · Reasoning · Math · Long documents · Following instructions
DeepSeek-V4-Flash is the stronger all-rounder.Claude Opus 4.5 is better at facts.
Scores updated · 45 tests both models report · How we compare
Where each one wins
Tests won in each of the seven areas where both have results. Each piece is one test, so a longer bar means more evidence; grey means the two scored within a point of each other.
- ReasoningHard problems that need careful thinking05DeepSeek-V4-Flash5 of 5 tests
- MathCompetition and research-level math14DeepSeek-V4-Flash4 of 6 tests · 1 tie
- AgentsCarrying out multi-step tasks on its own02DeepSeek-V4-Flash2 of 3 tests · 1 tie
- Following instructionsDoing exactly what it is asked02DeepSeek-V4-Flash2 of 2 tests
- Long documentsFinding answers in very long texts01DeepSeek-V4-Flash1 of 1 test
- FactsGetting facts right instead of making them up30Claude Opus 4.53 of 3 tests
- CodingWriting and fixing software43Claude Opus 4.54 of 9 tests · 2 ties
Long documents rests on a single test.
What it costs
Prices per million tokens, roughly 750,000 words. The bars show the cost of a million tokens read plus a million written.
DeepSeek-V4-Flash costs 94% less for the same work.
The biggest differences
The three tests each model wins by the widest margin. Scores are out of 100.
Where DeepSeek-V4-Flash pulls ahead
- Fixes real GitHub issues in many programming languagesSWE-bench Multilingual+66.3points ahead
- Finds hard-to-locate facts by browsing the webBrowseComp+36.2points ahead
- Abstract visual puzzles that people can solveARC-AGI-2+23.8points ahead
Where Claude Opus 4.5 pulls ahead
- Avoids making up answers it doesn't knowAA-Omniscience · Non-hallucination+30.7points ahead
- Short factual questions, answered correctlySimpleQA Verified+11.6points ahead
- Hard command-line tasks in a real terminalTerminal-Bench Hard+11.4points ahead
Every test, side by side
All 45 tests both models report. The winning score is in its model's colour; marks a score checked independently.
CodingClaude Opus 4.5
- SWE-bench MultilingualDeepSeek-V4-Flash by 66.3773.3+66.3
- Terminal-Bench HardClaude Opus 4.5 by 11.44735.6+11.4
- LiveBench · Agentic CodingDeepSeek-V4-Flash by 7.139.746.8+7.1
- LiveCodeBench v6DeepSeek-V4-Flash by 5.884.890.6+5.8
- LiveBench · CodingClaude Opus 4.5 by 4.779.775+4.7
- LMArena · WebDevClaude Opus 4.5 by 39 rating points14691430+39 rating
- SWE-bench VerifiedClaude Opus 4.5 by 1.980.979+1.9
- SciCodetie49.550.3tie
- SWE-bench Protie5252.6tie
AgentsDeepSeek-V4-Flash
- BrowseCompDeepSeek-V4-Flash by 36.23773.2+36.2
- MCP AtlasDeepSeek-V4-Flash by 6.762.369+6.7
- GDPValtie47.346.9tie
ReasoningDeepSeek-V4-Flash
- ARC-AGI-2DeepSeek-V4-Flash by 23.837.661.4+23.8
- CritPtDeepSeek-V4-Flash by 124.616.6+12
- Humanity's Last ExamDeepSeek-V4-Flash by 8.530.138.6+8.5
- LiveBench · ReasoningDeepSeek-V4-Flash by 6.580.186.6+6.5
- GPQA DiamondDeepSeek-V4-Flash by 4.286.690.8+4.2
FactsClaude Opus 4.5
- AA-Omniscience · Non-hallucinationClaude Opus 4.5 by 30.7398.3+30.7
- SimpleQA VerifiedClaude Opus 4.5 by 11.645.734.1+11.6
- AA-Omniscience · AccuracyClaude Opus 4.5 by 6.246.640.4+6.2
MathDeepSeek-V4-Flash
- FrontierMath Tiers 1-3 (v2)DeepSeek-V4-Flash by 23.134.457.5+23.1
- FrontierMath Tier 4DeepSeek-V4-Flash by 19.54.924.4+19.5
- HMMT Feb. 2026DeepSeek-V4-Flash by 9.585.394.8+9.5
- IMOAnswerBenchDeepSeek-V4-Flash by 4.48488.4+4.4
- LiveBench · MathematicsClaude Opus 4.5 by 3.690.486.8+3.6
- AIME 2026tie95.195.8tie
Long documentsDeepSeek-V4-Flash
- AA-LCRDeepSeek-V4-Flash by 2.477.379.7+2.4
Following instructionsDeepSeek-V4-Flash
- IFBenchDeepSeek-V4-Flash by 21.25879.2+21.2
- LiveBench · Instruction FollowingDeepSeek-V4-Flash by 2.962.565.5+2.9
Other results16 tests, not counted
Tests outside the eight areas. They are not counted above: several are summary scores built from other tests, or the same test under another name.
- AA-OmniscienceClaude Opus 4.5 by 28.314-14.3+28.3
- ToolathlonDeepSeek-V4-Flash by 26.843.570.3+26.8
- CyberGymDeepSeek-V4-Flash by 26.150.676.7+26.1
- Artificial Analysis Coding IndexDeepSeek-V4-Flash by 21.347.869.1+21.3
- AA Agentic IndexClaude Opus 4.5 by 17.959.641.7+17.9
- BrowseComp (context management)DeepSeek-V4-Flash by 15.457.873.2+15.4
- NL2RepoDeepSeek-V4-Flash by 1143.254.2+11
- ARC-AGI-1DeepSeek-V4-Flash by 78289+7
- τ²-Bench Telecom (AA run)DeepSeek-V4-Flash by 5.589.595+5.5
- AA IntelligenceDeepSeek-V4-Flash by 5.229.134.3+5.2
- livebench_data_analysisDeepSeek-V4-Flash by 4.974.479.3+4.9
- LiveCodeBenchDeepSeek-V4-Flash by 4.68791.6+4.6
- MMLU-ProClaude Opus 4.5 by 3.389.586.2+3.3
- Terminal-Bench 2.0Claude Opus 4.5 by 2.459.356.9+2.4
- livebench_languageClaude Opus 4.5 by 2.181.379.2+2.1
- HLE (with tools)DeepSeek-V4-Flash by 1.943.245.1+1.9
Questions people ask
Which is better, Claude Opus 4.5 or DeepSeek-V4-Flash?
DeepSeek-V4-Flash wins five of the seven areas where both have results: agents, reasoning, math, long documents and following instructions. Claude Opus 4.5 wins coding and facts.
Which is better for coding?
Claude Opus 4.5. It wins 4 of the 9 coding tests both models report; DeepSeek-V4-Flash wins 3, and 2 are ties.
Which is cheaper?
Claude Opus 4.5 costs $5.00 per million input tokens and $25.00 per million output tokens; DeepSeek-V4-Flash costs $0.44 and $1.32. That makes DeepSeek-V4-Flash about 94% cheaper for the same work.
How do you compare the two?
We use the 45 benchmark tests both models have published scores on. The verdict counts the 29 tests in the eight capability areas, and a gap under one point (ten on rating-style scales) counts as a tie. The other 16 are listed but not counted, because several are summary scores or repeat a test. Each score is the one shown on the model's own page.