DeepSeek-V4-Flash vs GPT-5.5
Wins 0 of 7 areas
—
Wins 6 of 7 areas
Coding · Agents · Reasoning · Facts · Math · Long documents
GPT-5.5 is the stronger all-rounder.DeepSeek-V4-Flash is cheaper.
Scores updated · 50 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.
- CodingWriting and fixing software07GPT-5.57 of 7 tests
- ReasoningHard problems that need careful thinking06GPT-5.56 of 6 tests
- MathCompetition and research-level math05GPT-5.55 of 5 tests
- AgentsCarrying out multi-step tasks on its own14GPT-5.54 of 6 tests · 1 tie
- FactsGetting facts right instead of making them up03GPT-5.53 of 3 tests
- Long documentsFinding answers in very long texts01GPT-5.51 of 1 test
- Following instructionsDoing exactly what it is asked11Even1 each
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 95% less for the same work.
The biggest differences
The tests each model wins by the widest margin, up to three each. Scores are out of 100.
Where GPT-5.5 pulls ahead
- Extremely hard research-level math problemsFrontierMath Tier 4+48.1points ahead
- Short factual questions, answered correctlySimpleQA Verified+28.9points ahead
- Unpublished advanced math problemsFrontierMath Tiers 1-3 (v2)+27.8points ahead
Every test, side by side
All 50 tests both models report. The winning score is in its model's colour; marks a score checked independently.
CodingGPT-5.5
- Terminal-Bench HardGPT-5.5 by 2535.660.6+25
- LMArena · WebDevGPT-5.5 by 83 rating points14301513+83 rating
- LiveBench · Agentic CodingGPT-5.5 by 7.246.854+7.2
- LiveBench · CodingGPT-5.5 by 7.27582.2+7.2
- SWE-bench ProGPT-5.5 by 652.658.6+6
- Terminal-Bench 2.1GPT-5.5 by 5.678.784.3+5.6
- SciCodeGPT-5.5 by 5.550.355.8+5.5
AgentsGPT-5.5
- AA IT-Bench SREGPT-5.5 by 14.331.545.8+14.3
- BrowseCompGPT-5.5 by 11.273.284.4+11.2
- MCP AtlasGPT-5.5 by 6.36975.3+6.3
- GDPValDeepSeek-V4-Flash by 4.246.942.7+4.2
- Terminal-Bench 4.0GPT-5.5 by 2.512.114.6+2.5
- τ-Bench V3 · Bankingtie39.439tie
ReasoningGPT-5.5
- ARC-AGI-2GPT-5.5 by 23.661.485+23.6
- SimpleBenchGPT-5.5 by 22.746.369+22.7
- CritPtGPT-5.5 by 10.516.627.1+10.5
- Humanity's Last ExamGPT-5.5 by 7.238.645.8+7.2
- LiveBench · ReasoningGPT-5.5 by 3.186.689.7+3.1
- GPQA DiamondGPT-5.5 by 2.790.893.5+2.7
FactsGPT-5.5
- SimpleQA VerifiedGPT-5.5 by 28.934.163+28.9
- AA-Omniscience · AccuracyGPT-5.5 by 17.640.458+17.6
- AA-Omniscience · Non-hallucinationGPT-5.5 by 2.78.311+2.7
MathGPT-5.5
- FrontierMath Tier 4GPT-5.5 by 48.124.472.5+48.1
- FrontierMath Tiers 1-3 (v2)GPT-5.5 by 27.857.585.3+27.8
- LiveBench · MathematicsGPT-5.5 by 9.186.895.9+9.1
- AIME 2026GPT-5.5 by 4.295.8100+4.2
- HMMT Feb. 2026GPT-5.5 by 3.794.898.5+3.7
Following instructionsEven
- LiveBench · Instruction FollowingGPT-5.5 by 5.265.570.7+5.2
- IFBenchDeepSeek-V4-Flash by 3.379.275.9+3.3
Other results20 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.
- GDPval-AA (Elo)GPT-5.5 by 374 rating points13951769+374 rating
- AA-OmniscienceGPT-5.5 by 34.8-14.320.5+34.8
- GDPval-AA v2GPT-5.5 by 320 rating points11891509+320 rating
- Terminal-Bench 2.0GPT-5.5 by 25.856.982.7+25.8
- DeepSWEGPT-5.5 by 15.654.470+15.6
- ToolathlonDeepSeek-V4-Flash by 14.770.355.6+14.7
- DeepSWE 1.1GPT-5.5 by 12.654.467+12.6
- livebench_languageGPT-5.5 by 8.279.287.4+8.2
- HLE (with tools)GPT-5.5 by 7.145.152.2+7.1
- ARC-AGI-1GPT-5.5 by 68995+6
- Artificial Analysis Coding IndexGPT-5.5 by 5.869.174.9+5.8
- CyberGymGPT-5.5 by 5.176.781.8+5.1
- AA Agentic IndexDeepSeek-V4-Flash by 4.441.737.3+4.4
- AA IntelligenceGPT-5.5 by 4.134.338.4+4.1
- NL2RepoDeepSeek-V4-Flash by 3.554.250.7+3.5
- Toolathlon VerifiedGPT-5.5 by 3.270.373.5+3.2
- JobBenchDeepSeek-V4-Flash by 341.338.3+3
- livebench_data_analysisGPT-5.5 by 2.379.381.6+2.3
- Agents' Last ExamGPT-5.5 by 1.425.226.6+1.4
- τ²-Bench Telecom (AA run)DeepSeek-V4-Flash by 1.19593.9+1.1
Questions people ask
Which is better, DeepSeek-V4-Flash or GPT-5.5?
GPT-5.5 wins six of the seven areas where both have results: coding, agents, reasoning, facts, math and long documents. DeepSeek-V4-Flash wins none, but costs 95% less. They are level on following instructions.
Which is better for coding?
GPT-5.5. It wins 7 of the 7 coding tests both models report; DeepSeek-V4-Flash wins none.
Which is cheaper?
DeepSeek-V4-Flash costs $0.44 per million input tokens and $1.32 per million output tokens; GPT-5.5 costs $5.00 and $30.00. That makes DeepSeek-V4-Flash about 95% cheaper for the same work.
How do you compare the two?
We use the 50 benchmark tests both models have published scores on. The verdict counts the 30 tests in the eight capability areas, and a gap under one point (ten on rating-style scales) counts as a tie. The other 20 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.