Claude Haiku 5.5 vs Gemini 3.8 Flash

Updated October 21, 2026. 61 benchmarks have a result for both. Coding is ranked on the Vibe Coding Index; every other board is shown as published.

Replace Claude Haiku 5.5 Replace Gemini 3.8 Flash

Claude Haiku 5.5Anthropic

Coding: 75.9
Overall: 43.4
Output $/M: $0.50

Gemini 3.8 FlashGoogle

Coding: 70.5
Overall: 40.9
Output $/M: $4.125

vs boards won of 61 shared, 1 tied

Decision reading

Pick Claude Haiku 5.5 for coding: it scores 75.9 on the Vibe Coding Index against 70.5 for Gemini 3.8 Flash.

Pick Gemini 3.8 Flash when the context window is larger, 1.05M against 1M tokens, or when what matters is IOI (Vals AI) or SciCode, where it leads.

Model AClaude Haiku 5.5Anthropic75.9/1002 independent benchmarksNo cost per solved task Model BGemini 3.8 FlashGoogle70.5/1002 independent benchmarks$2.74 per solved task

61165

Shared results: 61
Claude Haiku 5.5 only: 1
Gemini 3.8 Flash only: 65
Like-for-like categories: 8 of 9

Shared results can support a head-to-head reading. Results only one model has describe coverage, not superiority.

Which one for your work

Each card is decided by one number both models carry. Where only one has it, the card says so and makes no call.

Coding
Vibe Coding Index, four public coding benchmarks
Claude Haiku 5.5
Claude Haiku 5.5 scores 75.9 against 70.5.
2 benchmarks behind each score
Intelligence
AA Intelligence Index
Claude Haiku 5.5
Claude Haiku 5.5 leads, 43.4 against 40.9.
Same board, both measured
Agentic work
AA Agentic Index
No call
Only Gemini 3.8 Flash has a AA Agentic Index result, 40.2.
Directional only
Reasoning
GPQA Diamond
No call
Only Gemini 3.8 Flash has a GPQA Diamond result, 94.4%.
Directional only
Knowledge
MMLU Pro
No call
Only Gemini 3.8 Flash has a MMLU Pro result, 90.2%.
Directional only
Web design
Design Arena: websites
Gemini 3.8 Flash
Gemini 3.8 Flash leads, 1301 against 1263.
Same board, both measured
General
Vals Index
Claude Haiku 5.5
Claude Haiku 5.5 leads, 58.7% against 56.0%.
Same board, both measured
Long documents
Listed context window
Gemini 3.8 Flash
Gemini 3.8 Flash takes 1.05M tokens against 1M.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
Claude Haiku 5.5
Claude Haiku 5.5 $0.0003, Gemini 3.8 Flash $0.0029 per turn.
List prices
Cost per solved task
One SWE-bench Verified task, solved
No call
Only Gemini 3.8 Flash has the number, $2.74.
Directional only

At a glance

Coding index: Claude Haiku 5.5 75.9 from 2 benchmarks, Gemini 3.8 Flash 70.5 from 2 benchmarks.
Widest category: Knowledge, 24.7 points apart on average over 2 shared benchmarks.
Widest single gap: SimpleQA Verified: Claude Haiku 5.5 23.8% against Gemini 3.8 Flash 69.7%, 45.9 points apart on a 0 to 100 scale.
Output price: Claude Haiku 5.5 $0.50 against Gemini 3.8 Flash $4.125 per million output tokens, 8.3x apart.
Context window: Claude Haiku 5.5 takes 1M tokens, Gemini 3.8 Flash 1.05M.

Benchmark by benchmark

First the score: boards each model leads, per category, where both have a result. Then every board, a category to a fold; bars are each result on a 0 to 100 scale, so compare the two in a row, not one row with another.

Boards won, where both have a result
Category	Claude Haiku 5.5	Gemini 3.8 Flash	Ties
Coding	12	3
Intelligence	2	0
Agentic work	7	7
Reasoning	0	8
Math	3	0	1 tie
Knowledge	1	1
Web design	4	3
General	4	5
All shared boards	33	27	1 tie

CodingLike-for-likeFour of these boards feed the Vibe Coding Index123

Coding benchmarks for Claude Haiku 5.5 and Gemini 3.8 Flash
Benchmark	Claude Haiku 5.5	Gemini 3.8 Flash	Leader
LiveBench coding	91.4%	82.2%	Claude Haiku 5.5
LMArena WebDev	1586	1585	Claude Haiku 5.5
AA Coding Index	Not measured	76.3	Only Gemini 3.8 Flash measured
LiveCodeBench (Vals AI)	Not measured	89.5%	Only Gemini 3.8 Flash measured
SWE-bench Verified (Vals AI)	Not measured	80.0%	Only Gemini 3.8 Flash measured
Terminal-Bench 4 (Vals AI)	36.4%	19.7%	Claude Haiku 5.5
Vibe Code Bench (Vals AI)	90.4%	78.7%	Claude Haiku 5.5
Code migration (Vals AI)	44.6%	36.5%	Claude Haiku 5.5
ProgramBench (Vals AI)	2.5%	1.0%	Claude Haiku 5.5
IOI (Vals AI)	47.3%	56.9%	Gemini 3.8 Flash
Terminal-Bench 2.1 (Vals AI)	Not measured	81.3%	Only Gemini 3.8 Flash measured
SWE-bench Multimodal (Vals AI)	44.0%	40.8%	Claude Haiku 5.5
Vibe Code Bench 1-100 (Vals AI)	20.4%	18.8%	Claude Haiku 5.5
SkillsBench (Vals AI)	Not measured	58.0%	Only Gemini 3.8 Flash measured
CyberBench (Vals AI)	75.5%	43.8%	Claude Haiku 5.5
SciCode	55.0%	56.6%	Gemini 3.8 Flash
FrontierCode	46.4%	41.2%	Claude Haiku 5.5
FrontierSWE	43.8%	19.6%	Claude Haiku 5.5
WeirdML	Not measured	84.8%	Only Gemini 3.8 Flash measured
ALE-Bench	Not measured	1269.7	Only Gemini 3.8 Flash measured
LMArena Text: coding	Not measured	1508	Only Gemini 3.8 Flash measured
LMArena Text: software and IT	Not measured	1507	Only Gemini 3.8 Flash measured
LMArena WebDev: React	1605	1577	Claude Haiku 5.5
LMArena WebDev: HTML	1569	1616	Gemini 3.8 Flash
LMArena WebDev: from an image	Not measured	1593	Only Gemini 3.8 Flash measured
Neither model has a result on the other 13 boards here

IntelligenceLike-for-likePublic boards, shown as published, kept out of the index20

Intelligence benchmarks for Claude Haiku 5.5 and Gemini 3.8 Flash
Benchmark	Claude Haiku 5.5	Gemini 3.8 Flash	Leader
AA Intelligence Index	43.4	40.9	Claude Haiku 5.5
Epoch Capabilities Index	159.3	157.4	Claude Haiku 5.5

Agentic workLike-for-likePublic boards, shown as published, kept out of the index77

Agentic work benchmarks for Claude Haiku 5.5 and Gemini 3.8 Flash
Benchmark	Claude Haiku 5.5	Gemini 3.8 Flash	Leader
AA Agentic Index	Not measured	40.2	Only Gemini 3.8 Flash measured
Design Arena: agents building web apps	Not measured	1238	Only Gemini 3.8 Flash measured
Design Arena: agents building full-stack apps	Not measured	1244	Only Gemini 3.8 Flash measured
Design Arena: agents building mobile apps	Not measured	1236	Only Gemini 3.8 Flash measured
Design Arena: agents building Android apps	Not measured	1078	Only Gemini 3.8 Flash measured
Design Arena: agents building Godot games	Not measured	1273	Only Gemini 3.8 Flash measured
Design Arena: PowerPoint slides	Not measured	1178	Only Gemini 3.8 Flash measured
Design Arena: spreadsheets	Not measured	1052	Only Gemini 3.8 Flash measured
LiveBench research	81.9%	79.1%	Claude Haiku 5.5
LiveBench browser	80.0%	64.0%	Claude Haiku 5.5
LiveBench long agentic	57.6%	30.1%	Claude Haiku 5.5
SREBench (Vals AI)	5.7%	11.1%	Gemini 3.8 Flash
Finance Agent (Vals AI)	54.1%	61.4%	Gemini 3.8 Flash
Tax Agent Bench (Vals AI)	31.9%	32.1%	Gemini 3.8 Flash
Legal Research Bench (Vals AI)	43.3%	38.9%	Claude Haiku 5.5
Harvey's Legal Agent Benchmark (Vals AI)	4.2%	12.1%	Gemini 3.8 Flash
Excel Modeling Benchmark (Vals AI)	59.0%	72.2%	Gemini 3.8 Flash
BioMysteryBench (Vals AI)	70.4%	62.2%	Claude Haiku 5.5
Terminal-Bench-Science (Vals AI)	10.0%	8.6%	Claude Haiku 5.5
Vals Science Index	38.5%	35.8%	Claude Haiku 5.5
Time Horizon Index (Vals AI)	Not measured	18.8%	Only Gemini 3.8 Flash measured
CUA-bench (Vals AI)	Not measured	4.2%	Only Gemini 3.8 Flash measured
APEX-Agents	56.1%	64.3%	Gemini 3.8 Flash
Remote Labor Index	Not measured	5.8%	Only Gemini 3.8 Flash measured
Vending-Bench 2	$3,602	$5,094	Gemini 3.8 Flash
Neither model has a result on the other 14 boards here

ReasoningLike-for-likePublic boards, shown as published, kept out of the index08

Reasoning benchmarks for Claude Haiku 5.5 and Gemini 3.8 Flash
Benchmark	Claude Haiku 5.5	Gemini 3.8 Flash	Leader
GPQA Diamond	Not measured	94.4%	Only Gemini 3.8 Flash measured
LiveBench reasoning	82.4%	89.3%	Gemini 3.8 Flash
MysteryMechanism (Vals AI)	35.1%	36.5%	Gemini 3.8 Flash
MMMU Pro (Vals AI)	Not measured	89.1%	Only Gemini 3.8 Flash measured
GPQA Diamond (Artificial Analysis run)	Not measured	95.3%	Only Gemini 3.8 Flash measured
Humanity's Last Exam (Artificial Analysis run)	44.4%	47.8%	Gemini 3.8 Flash
GPQA Diamond (Epoch AI run)	89.6%	95.4%	Gemini 3.8 Flash
ARC-AGI	89.0%	98.5%	Gemini 3.8 Flash
ARC-AGI-2	61.3%	89.2%	Gemini 3.8 Flash
Chess puzzles	55.0%	58.0%	Gemini 3.8 Flash
Mystery game puzzles	30.0%	47.0%	Gemini 3.8 Flash
EBR-bench	43.8%	Not measured	Only Claude Haiku 5.5 measured
LMArena Text: hard prompts	Not measured	1509	Only Gemini 3.8 Flash measured
LMArena Text: expert	Not measured	1526	Only Gemini 3.8 Flash measured
LMArena Text: hard prompts in English	Not measured	1504	Only Gemini 3.8 Flash measured
LMArena Vision: diagrams	Not measured	1345	Only Gemini 3.8 Flash measured
LMArena Vision: homework	Not measured	1351	Only Gemini 3.8 Flash measured
Neither model has a result on the other 4 boards here

MathLike-for-likePublic boards, shown as published, kept out of the index30

Math benchmarks for Claude Haiku 5.5 and Gemini 3.8 Flash
Benchmark	Claude Haiku 5.5	Gemini 3.8 Flash	Leader
OTIS Mock AIME	98.9%	98.9%	Tie
FrontierMath, tiers 1 to 3	75.1%	68.4%	Claude Haiku 5.5
FrontierMath, tier 4	46.3%	22.0%	Claude Haiku 5.5
ProofBench	89.0%	48.0%	Claude Haiku 5.5
LMArena Text: math	Not measured	1532	Only Gemini 3.8 Flash measured
LMArena Text: mathematical work	Not measured	1519	Only Gemini 3.8 Flash measured
Neither model has a result on the other 7 boards here

KnowledgeLike-for-likePublic boards, shown as published, kept out of the index11

Knowledge benchmarks for Claude Haiku 5.5 and Gemini 3.8 Flash
Benchmark	Claude Haiku 5.5	Gemini 3.8 Flash	Leader
MMLU Pro	Not measured	90.2%	Only Gemini 3.8 Flash measured
LegalBench (Vals AI)	Not measured	87.0%	Only Gemini 3.8 Flash measured
TaxEval (Vals AI)	Not measured	74.5%	Only Gemini 3.8 Flash measured
MortgageTax (Vals AI)	Not measured	65.3%	Only Gemini 3.8 Flash measured
MedCode (Vals AI)	51.5%	48.1%	Claude Haiku 5.5
SimpleQA Verified	23.8%	69.7%	Gemini 3.8 Flash
LMArena Text: science	Not measured	1523	Only Gemini 3.8 Flash measured
LMArena Text: medicine and healthcare	Not measured	1508	Only Gemini 3.8 Flash measured
LMArena Text: legal and government	Not measured	1497	Only Gemini 3.8 Flash measured
LMArena Text: business and finance	Not measured	1479	Only Gemini 3.8 Flash measured
Neither model has a result on the other 7 boards here

Web designLike-for-likePublic boards, shown as published, kept out of the index43

Web design benchmarks for Claude Haiku 5.5 and Gemini 3.8 Flash
Benchmark	Claude Haiku 5.5	Gemini 3.8 Flash	Leader
Design Arena: websites	1263	1301	Gemini 3.8 Flash
Design Arena: UI components	1295	1318	Gemini 3.8 Flash
Design Arena: game dev	1315	1305	Claude Haiku 5.5
Design Arena: data viz	1292	1269	Claude Haiku 5.5
Design Arena: 3D	1343	1295	Claude Haiku 5.5
Design Arena: all code categories	1279	1304	Gemini 3.8 Flash
Design Arena: SVG	Not measured	1295	Only Gemini 3.8 Flash measured
Design Arena: ASCII art	Not measured	1264	Only Gemini 3.8 Flash measured
LiveBench design	83.1%	72.7%	Claude Haiku 5.5

GeneralLike-for-likePublic boards, shown as published, kept out of the index45

General benchmarks for Claude Haiku 5.5 and Gemini 3.8 Flash
Benchmark	Claude Haiku 5.5	Gemini 3.8 Flash	Leader
Vals Index	58.7%	56.0%	Claude Haiku 5.5
LiveBench data analysis	53.1%	54.0%	Gemini 3.8 Flash
Public Benefits Bench (Vals AI)	63.2%	65.3%	Gemini 3.8 Flash
SAGE (Vals AI)	45.8%	35.1%	Claude Haiku 5.5
MedScribe (Vals AI)	89.5%	84.5%	Claude Haiku 5.5
Long context reasoning (AA-LCR)	82.7%	84.0%	Gemini 3.8 Flash
DTBench	95.0%	95.7%	Gemini 3.8 Flash
LMCA	51.1%	52.9%	Gemini 3.8 Flash
Surface Evolver Bench	Not measured	76.9%	Only Gemini 3.8 Flash measured
Furniture assembly	47.5%	31.7%	Claude Haiku 5.5
LMArena Text	Not measured	1499	Only Gemini 3.8 Flash measured
LMArena Text: instruction following	Not measured	1492	Only Gemini 3.8 Flash measured
LMArena Text: creative writing	Not measured	1488	Only Gemini 3.8 Flash measured
LMArena Vision	Not measured	1315	Only Gemini 3.8 Flash measured
LMArena Text: English	Not measured	1498	Only Gemini 3.8 Flash measured
LMArena Text: non-English	Not measured	1491	Only Gemini 3.8 Flash measured
LMArena Text: Chinese	Not measured	1553	Only Gemini 3.8 Flash measured
LMArena Text: German	Not measured	1501	Only Gemini 3.8 Flash measured
LMArena Text: Japanese	Not measured	1507	Only Gemini 3.8 Flash measured
LMArena Text: Korean	Not measured	1464	Only Gemini 3.8 Flash measured
LMArena Text: French	Not measured	1496	Only Gemini 3.8 Flash measured
LMArena Text: Spanish	Not measured	1487	Only Gemini 3.8 Flash measured
LMArena Text: Russian	Not measured	1514	Only Gemini 3.8 Flash measured
LMArena Text: Polish	Not measured	1497	Only Gemini 3.8 Flash measured
LMArena Text: multi-turn	Not measured	1503	Only Gemini 3.8 Flash measured
LMArena Text: longer queries	Not measured	1507	Only Gemini 3.8 Flash measured
LMArena Text: writing and language	Not measured	1494	Only Gemini 3.8 Flash measured
LMArena Text: entertainment and media	Not measured	1480	Only Gemini 3.8 Flash measured
LMArena Vision: English	Not measured	1318	Only Gemini 3.8 Flash measured
LMArena Vision: Chinese	Not measured	1416	Only Gemini 3.8 Flash measured
LMArena Vision: reading text	Not measured	1333	Only Gemini 3.8 Flash measured
LMArena Vision: humor	Not measured	1321	Only Gemini 3.8 Flash measured
LMArena Vision: creative writing	Not measured	1299	Only Gemini 3.8 Flash measured
Neither model has a result on the other 13 boards here

Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared

Image generation benchmarks for Claude Haiku 5.5 and Gemini 3.8 Flash
Benchmark	Claude Haiku 5.5	Gemini 3.8 Flash	Leader
Neither model has a result on 5 boards here

What each workload costs

Three fixed token mixes at each model's listed price, so per-token rates become a bill.

Chat turn

1K input + 500 output tokens

Claude Haiku 5.5$0.0003Fits in one request

Gemini 3.8 Flash$0.0029Fits in one request

Claude Haiku 5.5 costs less

Repository review

50K input + 3K output tokens

Claude Haiku 5.5$0.0065Fits in one request

Gemini 3.8 Flash$0.054Fits in one request

Claude Haiku 5.5 costs less

Agent loop

200K input + 10K output tokens

Claude Haiku 5.5$0.025Fits in one request

Gemini 3.8 Flash$0.206Fits in one request

Claude Haiku 5.5 costs less

Listed OpenRouter rates, without cache or batch discounts. A workload that does not fit a model's context window would need splitting.

Specification differences

The leading value in a row is marked; a row with a missing value names no leader. Our two rows are marked in red.

Specifications of Claude Haiku 5.5 and Gemini 3.8 Flash
Specification	Anthropic Claude Haiku 5.5	Google Gemini 3.8 Flash
Maker	Anthropic	Google
Weights	No public weights listed	No public weights listed
Released	October 7, 2026	September 2, 2026
Context window	1M	1.05M
Input $/Mtok	$0.10	$0.825
Output $/Mtok	$0.50	$4.125
Coding index	75.9	70.5
Independent measurements behind it	2	2
Cost per solved task	Not computable	$2.74
Source	OpenRouter listing	OpenRouter listing

Questions

Is Claude Haiku 5.5 better than Gemini 3.8 Flash for coding?

Pick Claude Haiku 5.5 for coding: it scores 75.9 on the Vibe Coding Index against 70.5 for Gemini 3.8 Flash. Pick Gemini 3.8 Flash when the context window is larger, 1.05M against 1M tokens, or when what matters is IOI (Vals AI) or SciCode, where it leads.

Which is cheaper, Claude Haiku 5.5 or Gemini 3.8 Flash?

Claude Haiku 5.5 costs $0.10 per million input tokens and $0.50 per million output tokens; Gemini 3.8 Flash costs $0.825 and $4.125. Cost per solved task is known for Gemini 3.8 Flash only.

Which has the bigger context window, Claude Haiku 5.5 or Gemini 3.8 Flash?

Gemini 3.8 Flash, with 1.05M tokens against 1M.

How many benchmarks is the Claude Haiku 5.5 vs Gemini 3.8 Flash comparison based on?

61 benchmarks have a result for both models as of October 21, 2026. Claude Haiku 5.5's coding index rests on 2 independent benchmarks and Gemini 3.8 Flash's on 2. Where only one model has a result, the page says so instead of naming a winner.

Compare next

Embed this comparison on your site

Free under CC BY 4.0, while the source link stays visible. Preview the frame · Terms and other embeds

<iframe src="https://llmbenchmark.ai/embed/compare/claude-haiku-5-5-vs-gemini-3-8-flash" title="Claude Haiku 5.5 vs Gemini 3.8 Flash, LLMBenchmark.ai" width="100%" height="360" style="border:0;max-width:100%" loading="lazy"></iframe>
<p style="font:13px/1.4 sans-serif;margin:6px 0 0">Source: <a href="https://llmbenchmark.ai/compare/claude-haiku-5-5-vs-gemini-3-8-flash">LLMBenchmark.ai, Claude Haiku 5.5 vs Gemini 3.8 Flash</a></p>

Decision reading

Which one for your work

Coding

Intelligence

Agentic work

Reasoning

Knowledge

Web design

General

Long documents

Everyday cost

Cost per solved task

At a glance

Benchmark by benchmark

What each workload costs

Chat turn

Repository review

Agent loop

Specification differences

Questions

Compare next