Gemini 3.5 Flash vs GPT-5.5
Wins 3 of 8 areas
Facts · Images and charts · Following instructions
Wins 5 of 8 areas
Coding · Agents · Reasoning · Math · Long documents
GPT-5.5 is the stronger all-rounder.Gemini 3.5 Flash is cheaper and better at images and charts.
Scores updated · 56 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.
- CodingWriting and fixing software07GPT-5.57 of 7 tests
- MathCompetition and research-level math05GPT-5.55 of 5 tests
- ReasoningHard problems that need careful thinking15GPT-5.55 of 6 tests
- AgentsCarrying out multi-step tasks on its own24GPT-5.54 of 7 tests · 1 tie
- Long documentsFinding answers in very long texts01GPT-5.51 of 1 test
- Images and chartsUnderstanding pictures, charts and video20Gemini 3.5 Flash2 of 2 tests
- FactsGetting facts right instead of making them up21Gemini 3.5 Flash2 of 3 tests
- Following instructionsDoing exactly what it is asked10Gemini 3.5 Flash1 of 2 tests · 1 tie
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.
Gemini 3.5 Flash costs 70% 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+45.7points ahead
- Unpublished advanced math problemsFrontierMath Tiers 1-3 (v2)+22.5points ahead
- Hard command-line tasks in a real terminalTerminal-Bench Hard+19.7points ahead
Where Gemini 3.5 Flash pulls ahead
- Avoids making up answers it doesn't knowAA-Omniscience · Non-hallucination+26.8points ahead
- Long professional tasks in banking, consulting and lawAA ApexAgents+9.4points ahead
- Multi-step tasks using many real software toolsMCP Atlas+8.3points ahead
Every test, side by side
All 56 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 19.740.960.6+19.7
- Terminal-Bench 2.1GPT-5.5 by 5.678.784.3+5.6
- LiveBench · Agentic CodingGPT-5.5 by 54954+5
- LiveBench · CodingGPT-5.5 by 478.282.2+4
- SWE-bench ProGPT-5.5 by 3.555.158.6+3.5
- SciCodeGPT-5.5 by 1.953.955.8+1.9
- LMArena · WebDevGPT-5.5 by 13 rating points14991512+13 rating
AgentsGPT-5.5
- AA ApexAgentsGemini 3.5 Flash by 9.447.137.7+9.4
- MCP AtlasGemini 3.5 Flash by 8.383.675.3+8.3
- Terminal-Bench 4.0GPT-5.5 by 86.614.6+8
- GDPValGPT-5.5 by 7.535.242.7+7.5
- τ-Bench V3 · BankingGPT-5.5 by 6.832.239+6.8
- AA IT-Bench SREGPT-5.5 by 5.540.345.8+5.5
- OSWorld-Verifiedtie78.478.7tie
ReasoningGPT-5.5
- CritPtGPT-5.5 by 1413.127.1+14
- ARC-AGI-2GPT-5.5 by 12.972.185+12.9
- LiveBench · ReasoningGPT-5.5 by 7.78289.7+7.7
- SimpleBenchGemini 3.5 Flash by 7.776.769+7.7
- Humanity's Last ExamGPT-5.5 by 3.142.745.8+3.1
- GPQA DiamondGPT-5.5 by 1.392.293.5+1.3
FactsGemini 3.5 Flash
- AA-Omniscience · Non-hallucinationGemini 3.5 Flash by 26.837.811+26.8
- AA-Omniscience · AccuracyGPT-5.5 by 6.651.458+6.6
- SimpleQA VerifiedGemini 3.5 Flash by 3.266.263+3.2
Images and chartsGemini 3.5 Flash
- MMMU-ProGemini 3.5 Flash by 4.484.379.9+4.4
- LMArena · VisionGemini 3.5 Flash by 18 rating points13101292+18 rating
MathGPT-5.5
- FrontierMath Tier 4GPT-5.5 by 45.726.872.5+45.7
- FrontierMath Tiers 1-3 (v2)GPT-5.5 by 22.562.885.3+22.5
- LiveBench · MathematicsGPT-5.5 by 7.788.295.9+7.7
- AIME 2026GPT-5.5 by 595100+5
- HMMT Feb. 2026GPT-5.5 by 395.598.5+3
Following instructionsGemini 3.5 Flash
- LiveBench · Instruction FollowingGemini 3.5 Flash by 4.975.670.7+4.9
- IFBenchtie76.375.9tie
Other results23 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.
- DeepSWEGPT-5.5 by 333770+33
- DeepSWE 1.1GPT-5.5 by 303767+30
- frontiermath_tier_4_v1GPT-5.5 by 20.814.635.4+20.8
- livebench_data_analysisGPT-5.5 by 16.764.981.6+16.7
- GDPval-AA v2GPT-5.5 by 160 rating points13491509+160 rating
- GDPval-AA v2 EloGPT-5.5 by 142 rating points13491491+142 rating
- HiL-Bench (Tools-allowed)GPT-5.5 by 1227.739.7+12
- GDPval-AA (Elo)GPT-5.5 by 113 rating points16561769+113 rating
- AA Agentic IndexGPT-5.5 by 1027.337.3+10
- Terminal-Bench 2.0GPT-5.5 by 6.576.282.7+6.5
- Finance Agent v2Gemini 3.5 Flash by 6.157.951.8+6.1
- AA IntelligenceGPT-5.5 by 5.832.638.4+5.8
- LiveBenchGPT-5.5 by 5.77580.7+5.7
- matharena_visual_math_overallGPT-5.5 by 589.994.9+5
- Artificial Analysis Coding IndexGPT-5.5 by 4.870.174.9+4.8
- livebench_languageGPT-5.5 by 2.884.687.4+2.8
- ARC-AGI-1GPT-5.5 by 2.592.595+2.5
- Finance AgentGPT-5.5 by 2.157.960+2.1
- τ²-Bench Telecom (AA run)Gemini 3.5 Flash by 1.495.393.9+1.4
- Legal Agent BenchmarkGPT-5.5 by 1.30.82.1+1.3
- Legal Agent Benchmark (Harvey's Held-Out Set)GPT-5.5 by 1.30.82.1+1.3
- Toolathlontie56.555.6tie
- AA-Omnisciencetie21.220.5tie
Questions people ask
Which is better, Gemini 3.5 Flash or GPT-5.5?
GPT-5.5 wins five of the eight areas we test: coding, agents, reasoning, math and long documents. Gemini 3.5 Flash wins facts, images and charts and following instructions, and costs 70% less.
Which is better for coding?
GPT-5.5. It wins 7 of the 7 coding tests both models report; Gemini 3.5 Flash wins none.
Which is cheaper?
Gemini 3.5 Flash costs $1.50 per million input tokens and $9.00 per million output tokens; GPT-5.5 costs $5.00 and $30.00. That makes Gemini 3.5 Flash about 70% cheaper for the same work.
How do you compare the two?
We use the 56 benchmark tests both models have published scores on. The verdict counts the 33 tests in the eight capability areas, and a gap under one point (ten on rating-style scales) counts as a tie. The other 23 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.