Claude Fable 5.1 vs Gemini 3.8 Flash
Wins 6 of 8 areas
Coding · Agents · Reasoning · Facts · Math · Long documents
Wins 1 of 8 areas
Following instructions
Claude Fable 5.1 is the stronger all-rounder.Gemini 3.8 Flash is cheaper and better at following instructions.
Both rank among the ten best models we track in reasoning and facts.
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.
- CodingWriting and fixing software50Claude Fable 5.15 of 5 tests
- ReasoningHard problems that need careful thinking41Claude Fable 5.14 of 6 tests · 1 tie
- MathCompetition and research-level math30Claude Fable 5.13 of 3 tests
- AgentsCarrying out multi-step tasks on its own31Claude Fable 5.13 of 4 tests
- FactsGetting facts right instead of making them up21Claude Fable 5.12 of 3 tests
- Long documentsFinding answers in very long texts10Claude Fable 5.11 of 1 test
- Following instructionsDoing exactly what it is asked01Gemini 3.8 Flash1 of 1 test
- Images and chartsUnderstanding pictures, charts and video00Even0 each · 1 tie
Images and charts, 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.
Gemini 3.8 Flash costs 93% less for the same work.
The biggest differences
The three tests each model wins by the widest margin. Scores are out of 100.
Where Claude Fable 5.1 pulls ahead
- Extremely hard research-level math problemsFrontierMath Tier 4+65.8points ahead
- Complex command-line tasks across many fieldsTerminal-Bench 4.0+32.3points ahead
- Unpublished advanced math problemsFrontierMath Tiers 1-3 (v2)+21.8points ahead
Where Gemini 3.8 Flash pulls ahead
- Avoids making up answers it doesn't knowAA-Omniscience · Non-hallucination+17.4points ahead
- Follows detailed instructions exactlyLiveBench · Instruction Following+8.4points ahead
- Finds the root cause of IT system incidentsAA IT-Bench SRE+3points 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.
CodingClaude Fable 5.1
- LMArena · WebDevClaude Fable 5.1 by 156 rating points17421586+156 rating
- LiveBench · CodingClaude Fable 5.1 by 13.986.472.5+13.9
- LiveBench · Agentic CodingClaude Fable 5.1 by 11.966.154.2+11.9
- SciCodeClaude Fable 5.1 by 6.563.156.6+6.5
- Terminal-Bench 2.1Claude Fable 5.1 by 3.891.487.6+3.8
AgentsClaude Fable 5.1
- Terminal-Bench 4.0Claude Fable 5.1 by 32.35219.7+32.3
- GDPValClaude Fable 5.1 by 15.962.746.8+15.9
- AA IT-Bench SREGemini 3.8 Flash by 349.552.5+3
- τ-Bench V3 · BankingClaude Fable 5.1 by 2.347.244.9+2.3
ReasoningClaude Fable 5.1
- CritPtClaude Fable 5.1 by 11.429.718.3+11.4
- Humanity's Last ExamClaude Fable 5.1 by 11.359.147.8+11.3
- SimpleBenchClaude Fable 5.1 by 4.286.682.4+4.2
- LiveBench · ReasoningClaude Fable 5.1 by 2.491.789.3+2.4
- GPQA DiamondGemini 3.8 Flash by 1.693.795.3+1.6
- ARC-AGI-2tie9089.2tie
FactsClaude Fable 5.1
- AA-Omniscience · Non-hallucinationGemini 3.8 Flash by 17.427.444.8+17.4
- AA-Omniscience · AccuracyClaude Fable 5.1 by 12.667.254.6+12.6
- SimpleQA VerifiedClaude Fable 5.1 by 1.170.869.7+1.1
MathClaude Fable 5.1
- FrontierMath Tier 4Claude Fable 5.1 by 65.887.821.9+65.8
- FrontierMath Tiers 1-3 (v2)Claude Fable 5.1 by 21.890.268.4+21.8
- LiveBench · MathematicsClaude Fable 5.1 by 5.49791.6+5.4
Following instructionsGemini 3.8 Flash
- LiveBench · Instruction FollowingGemini 3.8 Flash by 8.47381.4+8.4
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.
- GDP (Surge AI)Claude Fable 5.1 by 50.185.135+50.1
- Terminal-Bench 4.0Claude Fable 5.1 by 36.755.819.1+36.7
- GDPval-AA v2Claude Fable 5.1 by 308 rating points18531545+308 rating
- GDPval-AA v2 EloClaude Fable 5.1 by 290 rating points18351545+290 rating
- livebench_data_analysisClaude Fable 5.1 by 26.380.354+26.3
- HiL-Bench (Tools-allowed)Claude Fable 5.1 by 2061.541.5+20
- OSWorld 2.0Claude Fable 5.1 by 18.977.959+18.9
- OSWorld 2.0 (partial)Claude Fable 5.1 by 18.977.959+18.9
- AA Agentic IndexClaude Fable 5.1 by 16.95841.1+16.9
- AA-OmniscienceClaude Fable 5.1 by 13.943.529.6+13.9
- AA IntelligenceClaude Fable 5.1 by 12.553.440.9+12.5
- LVBenchGemini 3.8 Flash by 7.479.787.1+7.4
- DeepSWE 1.1Gemini 3.8 Flash by 6.367.473.7+6.3
- Artificial Analysis Coding IndexClaude Fable 5.1 by 5.381.676.3+5.3
- livebench_languageClaude Fable 5.1 by 1.789.587.8+1.7
- ARC-AGI-1Gemini 3.8 Flash by 197.598.5+1
Questions people ask
Which is better, Claude Fable 5.1 or Gemini 3.8 Flash?
Claude Fable 5.1 wins six of the eight areas we test: coding, agents, reasoning, facts, math and long documents. Gemini 3.8 Flash wins following instructions, and costs 93% less. They are level on images and charts.
Which is better for coding?
Claude Fable 5.1. It wins 5 of the 5 coding tests both models report; Gemini 3.8 Flash wins none.
Which is cheaper?
Claude Fable 5.1 costs $10.00 per million input tokens and $50.00 per million output tokens; Gemini 3.8 Flash costs $0.75 and $3.75. That makes Gemini 3.8 Flash about 93% 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 24 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.