DeepSeek-V4.1-Flash vs GPT-5.5
Wins 2 of 8 areas
Coding · Agents
Wins 4 of 8 areas
Reasoning · Facts · Images and charts · Math
GPT-5.5 wins more areas, narrowly.DeepSeek-V4.1-Flash is cheaper and better at agents.
Scores updated · 40 tests both models report · How we compare
Where each one wins
Tests won in each of the eight areas we test. 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 thinking06GPT-5.56 of 7 tests · 1 tie
- FactsGetting facts right instead of making them up03GPT-5.53 of 3 tests
- MathCompetition and research-level math03GPT-5.53 of 3 tests
- Images and chartsUnderstanding pictures, charts and video02GPT-5.52 of 2 tests
- AgentsCarrying out multi-step tasks on its own30DeepSeek-V4.1-Flash3 of 3 tests
- CodingWriting and fixing software32DeepSeek-V4.1-Flash3 of 5 tests
- Long documentsFinding answers in very long texts00Even0 each · 1 tie
- Following instructionsDoing exactly what it is asked00Even0 each · 1 tie
Long documents and following instructions rest on a single test each.
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-V4.1-Flash costs 96% less for the same work.
The biggest differences
The three tests each model wins by the widest margin. Scores are out of 100.
Where GPT-5.5 pulls ahead
- Extremely hard research-level math problemsFrontierMath Tier 4+26.2points ahead
- Short factual questions, answered correctlySimpleQA Verified+20.1points ahead
- Unpublished advanced math problemsFrontierMath Tiers 1-3 (v2)+14.1points ahead
Where DeepSeek-V4.1-Flash pulls ahead
- Fixes real GitHub issues, working as an agentLiveBench · Agentic Coding+23.3points ahead
- Real work tasks from 44 professionsGDPVal+12.5points ahead
- Complex command-line tasks across many fieldsTerminal-Bench 4.0+12.2points ahead
Every test, side by side
All 40 tests both models report. The winning score is in its model's colour; marks a score checked independently.
CodingDeepSeek-V4.1-Flash
- LiveBench · Agentic CodingDeepSeek-V4.1-Flash by 23.377.354+23.3
- LMArena · WebDevDeepSeek-V4.1-Flash by 133 rating points16191486+133 rating
- Terminal-Bench 2.1DeepSeek-V4.1-Flash by 6.390.684.3+6.3
- SciCodeGPT-5.5 by 3.951.955.8+3.9
- LiveBench · CodingGPT-5.5 by 2.28082.2+2.2
AgentsDeepSeek-V4.1-Flash
- GDPValDeepSeek-V4.1-Flash by 12.55542.5+12.5
- Terminal-Bench 4.0DeepSeek-V4.1-Flash by 12.226.814.6+12.2
- AA IT-Bench SREDeepSeek-V4.1-Flash by 1.146.945.8+1.1
ReasoningGPT-5.5
- CritPtGPT-5.5 by 12.814.327.1+12.8
- ARC-AGI-2GPT-5.5 by 6.978.185+6.9
- Humanity's Last ExamGPT-5.5 by 6.639.245.8+6.6
- LiveBench · ReasoningGPT-5.5 by 386.789.7+3
- GPQA DiamondGPT-5.5 by 2.690.993.5+2.6
- SimpleBenchGPT-5.5 by 2.366.769+2.3
- ARC-AGI-3tie0.90.4tie
FactsGPT-5.5
- SimpleQA VerifiedGPT-5.5 by 20.142.963+20.1
- AA-Omniscience · AccuracyGPT-5.5 by 11.646.458+11.6
- AA-Omniscience · Non-hallucinationGPT-5.5 by 7.53.511+7.5
Images and chartsGPT-5.5
- MMMU-ProGPT-5.5 by 2.97779.9+2.9
- LMArena · VisionGPT-5.5 by 15 rating points12781293+15 rating
MathGPT-5.5
- FrontierMath Tier 4GPT-5.5 by 26.246.372.5+26.2
- FrontierMath Tiers 1-3 (v2)GPT-5.5 by 14.171.285.3+14.1
- LiveBench · MathematicsGPT-5.5 by 2.693.395.9+2.6
Following instructionsEven
- LiveBench · Instruction Followingtie7070.7tie
Other results15 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.
- Program BenchGPT-5.5 by 50.520.370.8+50.5
- BabyVisionDeepSeek-V4.1-Flash by 33.789.655.9+33.7
- AA-OmniscienceGPT-5.5 by 25.8-5.320.5+25.8
- NL2RepoDeepSeek-V4.1-Flash by 13.36450.7+13.3
- HLE (with tools)DeepSeek-V4.1-Flash by 11.763.952.2+11.7
- DeepSWE 1.1DeepSeek-V4.1-Flash by 7.274.267+7.2
- CyberGymDeepSeek-V4.1-Flash by 6.388.181.8+6.3
- livebench_languageGPT-5.5 by 6.281.287.4+6.2
- Agents' Last ExamDeepSeek-V4.1-Flash by 5.231.826.6+5.2
- vectara_factual_consistencyDeepSeek-V4.1-Flash by 5.195.890.7+5.1
- livebench_data_analysisGPT-5.5 by 2.379.381.6+2.3
- vectara_avg_summary_lengthGPT-5.5 by 21.4 rating points108.2129.6+21.4 rating
- ARC-AGI-1GPT-5.5 by 1.593.595+1.5
- AA IntelligenceDeepSeek-V4.1-Flash by 1.139.538.4+1.1
- vectara_answer_ratetie99.9100tie
Questions people ask
Which is better, DeepSeek-V4.1-Flash or GPT-5.5?
GPT-5.5 wins four of the eight areas we test: reasoning, facts, images and charts and math. DeepSeek-V4.1-Flash wins coding and agents, and costs 96% less. They are level on long documents and following instructions.
Which is better for coding?
DeepSeek-V4.1-Flash. It wins 3 of the 5 coding tests both models report; GPT-5.5 wins 2.
Which is cheaper?
DeepSeek-V4.1-Flash costs $0.30 per million input tokens and $1.20 per million output tokens; GPT-5.5 costs $5.00 and $30.00. That makes DeepSeek-V4.1-Flash about 96% cheaper for the same work.
How do you compare the two?
We use the 40 benchmark tests both models have published scores on. The verdict counts the 25 tests in the eight capability areas, and a gap under one point (ten on rating-style scales) counts as a tie. The other 15 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.