Claude Opus 4.8 vs Gemini 2.5 Flash (Sep) (Non-Reasoning)
Wins 7 of 7 areas
Coding · Agents · Reasoning · Facts · Images and charts · Long documents · Following instructions
Wins 0 of 7 areas
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Claude Opus 4.8 is the stronger all-rounder.
Scores updated · 16 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 thinking30Claude Opus 4.83 of 3 tests
- CodingWriting and fixing software20Claude Opus 4.82 of 2 tests
- FactsGetting facts right instead of making them up20Claude Opus 4.82 of 2 tests
- AgentsCarrying out multi-step tasks on its own10Claude Opus 4.81 of 1 test
- Images and chartsUnderstanding pictures, charts and video10Claude Opus 4.81 of 1 test
- Long documentsFinding answers in very long texts10Claude Opus 4.81 of 1 test
- Following instructionsDoing exactly what it is asked10Claude Opus 4.81 of 1 test
Agents, 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.
The biggest differences
The tests each model wins by the widest margin, up to three each. Scores are out of 100.
Where Claude Opus 4.8 pulls ahead
- Avoids making up answers it doesn't knowAA-Omniscience · Non-hallucination+50.6points ahead
- Hard command-line tasks in a real terminalTerminal-Bench Hard+41.6points ahead
- Very hard expert questions across many subjectsHumanity's Last Exam+34.9points ahead
Where Gemini 2.5 Flash (Sep) (Non-Reasoning) pulls ahead
No clear win on a test scored out of 100.
Every test, side by side
All 16 tests both models report. The winning score is in its model's colour; marks a score checked independently.
CodingClaude Opus 4.8
- Terminal-Bench HardClaude Opus 4.8 by 41.658.316.7+41.6
- SciCodeClaude Opus 4.8 by 13.954.440.5+13.9
ReasoningClaude Opus 4.8
- Humanity's Last ExamClaude Opus 4.8 by 34.948.713.8+34.9
- CritPtClaude Opus 4.8 by 20.620.90.3+20.6
- GPQA DiamondClaude Opus 4.8 by 12.79279.3+12.7
FactsClaude Opus 4.8
- AA-Omniscience · Non-hallucinationClaude Opus 4.8 by 50.660.710.1+50.6
- AA-Omniscience · AccuracyClaude Opus 4.8 by 20.548.828.3+20.5
Images and chartsClaude Opus 4.8
- LMArena · VisionClaude Opus 4.8 by 41 rating points12951254+41 rating
Following instructionsClaude Opus 4.8
- IFBenchClaude Opus 4.8 by 9.962.252.3+9.9
Other results5 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 4.8 by 64.928.8-36.1+64.9
- Artificial Analysis Coding IndexClaude Opus 4.8 by 49.774.324.6+49.7
- τ²-Bench Telecom (AA run)Claude Opus 4.8 by 48.894.445.6+48.8
- AA IntelligenceClaude Opus 4.8 by 26.341.815.5+26.3
- AA Agentic IndexClaude Opus 4.8 by 7.942.634.7+7.9
Questions people ask
Which is better, Claude Opus 4.8 or Gemini 2.5 Flash (Sep) (Non-Reasoning)?
Claude Opus 4.8 wins all seven areas where both have results: coding, agents, reasoning, facts, images and charts, long documents and following instructions. Gemini 2.5 Flash (Sep) (Non-Reasoning) wins none.
Which is better for coding?
Claude Opus 4.8. It wins 2 of the 2 coding tests both models report; Gemini 2.5 Flash (Sep) (Non-Reasoning) wins none.
How do you compare the two?
We use the 16 benchmark tests both models have published scores on. The verdict counts the 11 tests in the eight capability areas, and a gap under one point (ten on rating-style scales) counts as a tie. The other 5 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.