Claude Opus 4.5 vs Codestral 2508
Updated October 21, 2026. 6 benchmarks have a result for both. Coding is ranked on the Vibe Coding Index; every other board is shown as published.
Decision reading
Only Claude Opus 4.5 has a coding score, 44.0 on the Vibe Coding Index; Codestral 2508 has none, so the two cannot be ranked on coding.
Codestral 2508 has the edge where output tokens cost 27.8x less, and where the context window is larger, 256K against 200K tokens.
- Shared results
- 6
- Claude Opus 4.5 only
- 99
- Codestral 2508 only
- 1
- Like-for-like categories
- 1 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, six public coding benchmarks
No call
Only Claude Opus 4.5 has a coding score, so no call is made.
One side not measured
Intelligence
AA Intelligence Index
No call
Only Claude Opus 4.5 has a AA Intelligence Index result, 29.1.
Directional only
Reasoning
GPQA Diamond
No call
Only Claude Opus 4.5 has a GPQA Diamond result, 85.9%.
Directional only
Math
AIME
No call
Only Claude Opus 4.5 has a AIME result, 95.4%.
Directional only
Knowledge
MMLU Pro
No call
Only Claude Opus 4.5 has a MMLU Pro result, 87.3%.
Directional only
Web design
Design Arena: websites
Claude Opus 4.5
Claude Opus 4.5 leads, 1247 against 1013.
Same board, both measured
Long documents
Listed context window
Codestral 2508
Codestral 2508 takes 256K tokens against 200K.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
Codestral 2508
Claude Opus 4.5 $0.018, Codestral 2508 $0.0008 per turn.
List prices
Cost per solved task
One SWE-bench Verified task, solved
No call
Only Claude Opus 4.5 has the number, $1.37.
Directional only
At a glance
- Coding index
- Claude Opus 4.5 44.0 from 3 benchmarks, Codestral 2508 not benchmarked.
- Widest category
- Web design, 28.6 points apart on average over 6 shared benchmarks.
- Widest single gap
- Design Arena: game dev: Claude Opus 4.5 1229 against Codestral 2508 968, 32.6 points apart on a 0 to 100 scale.
- Output price
- Claude Opus 4.5 $25.00 against Codestral 2508 $0.90 per million output tokens, 27.8x apart.
- Context window
- Claude Opus 4.5 takes 200K tokens, Codestral 2508 256K.
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.
| Category | Claude Opus 4.5 | Bars | Codestral 2508 | Ties |
|---|---|---|---|---|
| Web design | 6 | 0 | ||
| All shared boards | 6 | 0 |
CodingDirectional onlySix of these boards feed the Vibe Coding Index18 boards, none shared
| Benchmark | Claude Opus 4.5 | Codestral 2508 | Leader |
|---|---|---|---|
| SWE-bench Verified | 79.2% | Not measured | Only Claude Opus 4.5 measured |
| SWE-bench (full test set) | 52.6% | Not measured | Only Claude Opus 4.5 measured |
| SWE-bench Multilingual | 70.7% | Not measured | Only Claude Opus 4.5 measured |
| LMArena WebDev | 1494 | Not measured | Only Claude Opus 4.5 measured |
| LiveCodeBench (Vals AI) | 83.7% | Not measured | Only Claude Opus 4.5 measured |
| SWE-bench Verified (Vals AI) | 76.4% | Not measured | Only Claude Opus 4.5 measured |
| Vibe Code Bench (Vals AI) | 20.6% | Not measured | Only Claude Opus 4.5 measured |
| LiveCodeBench (Artificial Analysis run) | 87.1% | Not measured | Only Claude Opus 4.5 measured |
| Terminal-Bench Hard (Artificial Analysis run) | 47.0% | Not measured | Only Claude Opus 4.5 measured |
| Terminal-Bench | 63.1% | Not measured | Only Claude Opus 4.5 measured |
| GSO-Bench | 26.5% | Not measured | Only Claude Opus 4.5 measured |
| WeirdML | 63.7% | Not measured | Only Claude Opus 4.5 measured |
| Cybench | 82.0% | Not measured | Only Claude Opus 4.5 measured |
| ALE-Bench | Not measured | 137.8 | Only Codestral 2508 measured |
| LMArena Text: coding | 1503 | Not measured | Only Claude Opus 4.5 measured |
| LMArena Text: software and IT | 1483 | Not measured | Only Claude Opus 4.5 measured |
| LMArena WebDev: React | 1478 | Not measured | Only Claude Opus 4.5 measured |
| LMArena WebDev: HTML | 1510 | Not measured | Only Claude Opus 4.5 measured |
| Neither model has a result on the other 20 boards here | |||
IntelligenceDirectional onlyPublic boards, shown as published, kept out of the index2 boards, none shared
| Benchmark | Claude Opus 4.5 | Codestral 2508 | Leader |
|---|---|---|---|
| AA Intelligence Index | 29.1 | Not measured | Only Claude Opus 4.5 measured |
| Epoch Capabilities Index | 150.1 | Not measured | Only Claude Opus 4.5 measured |
Agentic workDirectional onlyPublic boards, shown as published, kept out of the index12 boards, none shared
| Benchmark | Claude Opus 4.5 | Codestral 2508 | Leader |
|---|---|---|---|
| Design Arena: agents building web apps | 1159 | Not measured | Only Claude Opus 4.5 measured |
| Design Arena: agents building full-stack apps | 1156 | Not measured | Only Claude Opus 4.5 measured |
| Design Arena: agents building mobile apps | 1189 | Not measured | Only Claude Opus 4.5 measured |
| Design Arena: agents building Android apps | 1183 | Not measured | Only Claude Opus 4.5 measured |
| τ²-Bench Telecom | 89.5% | Not measured | Only Claude Opus 4.5 measured |
| METR time horizons | 75.0% | Not measured | Only Claude Opus 4.5 measured |
| Remote Labor Index | 3.8% | Not measured | Only Claude Opus 4.5 measured |
| GDPval | 45.5% | Not measured | Only Claude Opus 4.5 measured |
| BALROG | 43.5% | Not measured | Only Claude Opus 4.5 measured |
| DeepResearch Bench | 54.8% | Not measured | Only Claude Opus 4.5 measured |
| OSWorld | 66.3% | Not measured | Only Claude Opus 4.5 measured |
| Vending-Bench 2 | $4,967 | Not measured | Only Claude Opus 4.5 measured |
| Neither model has a result on the other 27 boards here | |||
ReasoningDirectional onlyPublic boards, shown as published, kept out of the index15 boards, none shared
| Benchmark | Claude Opus 4.5 | Codestral 2508 | Leader |
|---|---|---|---|
| GPQA Diamond | 85.9% | Not measured | Only Claude Opus 4.5 measured |
| MMMU Pro (Vals AI) | 83.0% | Not measured | Only Claude Opus 4.5 measured |
| GPQA Diamond (Artificial Analysis run) | 86.6% | Not measured | Only Claude Opus 4.5 measured |
| Humanity's Last Exam (Artificial Analysis run) | 30.1% | Not measured | Only Claude Opus 4.5 measured |
| GPQA Diamond (Epoch AI run) | 86.0% | Not measured | Only Claude Opus 4.5 measured |
| ARC-AGI | 80.0% | Not measured | Only Claude Opus 4.5 measured |
| ARC-AGI-2 | 37.6% | Not measured | Only Claude Opus 4.5 measured |
| SimpleBench | 62.0% | Not measured | Only Claude Opus 4.5 measured |
| Chess puzzles | 14.0% | Not measured | Only Claude Opus 4.5 measured |
| Mystery game puzzles | 22.0% | Not measured | Only Claude Opus 4.5 measured |
| EBR-bench | 14.3% | Not measured | Only Claude Opus 4.5 measured |
| VPCT | 40.0% | Not measured | Only Claude Opus 4.5 measured |
| LMArena Text: hard prompts | 1476 | Not measured | Only Claude Opus 4.5 measured |
| LMArena Text: expert | 1487 | Not measured | Only Claude Opus 4.5 measured |
| LMArena Text: hard prompts in English | 1482 | Not measured | Only Claude Opus 4.5 measured |
| Neither model has a result on the other 6 boards here | |||
MathDirectional onlyPublic boards, shown as published, kept out of the index10 boards, none shared
| Benchmark | Claude Opus 4.5 | Codestral 2508 | Leader |
|---|---|---|---|
| AIME | 95.4% | Not measured | Only Claude Opus 4.5 measured |
| MGSM (Vals AI) | 95.2% | Not measured | Only Claude Opus 4.5 measured |
| AA Math Index | 91.3 | Not measured | Only Claude Opus 4.5 measured |
| AIME 2025 (Artificial Analysis run) | 91.3% | Not measured | Only Claude Opus 4.5 measured |
| OTIS Mock AIME | 86.1% | Not measured | Only Claude Opus 4.5 measured |
| FrontierMath, tiers 1 to 3 | 34.4% | Not measured | Only Claude Opus 4.5 measured |
| FrontierMath, tier 4 | 4.9% | Not measured | Only Claude Opus 4.5 measured |
| ProofBench | 36.0% | Not measured | Only Claude Opus 4.5 measured |
| LMArena Text: math | 1463 | Not measured | Only Claude Opus 4.5 measured |
| LMArena Text: mathematical work | 1468 | Not measured | Only Claude Opus 4.5 measured |
| Neither model has a result on the other 3 boards here | |||
KnowledgeDirectional onlyPublic boards, shown as published, kept out of the index15 boards, none shared
| Benchmark | Claude Opus 4.5 | Codestral 2508 | Leader |
|---|---|---|---|
| MMLU Pro | 87.3% | Not measured | Only Claude Opus 4.5 measured |
| LegalBench (Vals AI) | 84.6% | Not measured | Only Claude Opus 4.5 measured |
| CaseLaw (Vals AI) | 62.6% | Not measured | Only Claude Opus 4.5 measured |
| CorpFin (Vals AI) | 65.1% | Not measured | Only Claude Opus 4.5 measured |
| TaxEval (Vals AI) | 74.9% | Not measured | Only Claude Opus 4.5 measured |
| MortgageTax (Vals AI) | 68.7% | Not measured | Only Claude Opus 4.5 measured |
| MedQA (Vals AI) | 95.9% | Not measured | Only Claude Opus 4.5 measured |
| MedCode (Vals AI) | 49.2% | Not measured | Only Claude Opus 4.5 measured |
| MMLU Pro (Artificial Analysis run) | 89.5% | Not measured | Only Claude Opus 4.5 measured |
| SimpleQA Verified | 45.7% | Not measured | Only Claude Opus 4.5 measured |
| GeoBench | 75.0% | Not measured | Only Claude Opus 4.5 measured |
| LMArena Text: science | 1454 | Not measured | Only Claude Opus 4.5 measured |
| LMArena Text: medicine and healthcare | 1444 | Not measured | Only Claude Opus 4.5 measured |
| LMArena Text: legal and government | 1459 | Not measured | Only Claude Opus 4.5 measured |
| LMArena Text: business and finance | 1448 | Not measured | Only Claude Opus 4.5 measured |
| Neither model has a result on the other 2 boards here | |||
Web designLike-for-likePublic boards, shown as published, kept out of the index60
| Benchmark | Claude Opus 4.5 | Codestral 2508 | Leader |
|---|---|---|---|
| Design Arena: websites | 1247 | 1013 | Claude Opus 4.5 |
| Design Arena: UI components | 1238 | 1017 | Claude Opus 4.5 |
| Design Arena: game dev | 1229 | 968 | Claude Opus 4.5 |
| Design Arena: data viz | 1243 | 1017 | Claude Opus 4.5 |
| Design Arena: 3D | 1214 | 1020 | Claude Opus 4.5 |
| Design Arena: all code categories | 1242 | 1007 | Claude Opus 4.5 |
| Design Arena: SVG | 1181 | Not measured | Only Claude Opus 4.5 measured |
| Design Arena: ASCII art | 1190 | Not measured | Only Claude Opus 4.5 measured |
| Neither model has a result on the other 1 board here | |||
GeneralDirectional onlyPublic boards, shown as published, kept out of the index26 boards, none shared
| Benchmark | Claude Opus 4.5 | Codestral 2508 | Leader |
|---|---|---|---|
| SAGE (Vals AI) | 52.1% | Not measured | Only Claude Opus 4.5 measured |
| MedScribe (Vals AI) | 85.3% | Not measured | Only Claude Opus 4.5 measured |
| IFBench | 58.0% | Not measured | Only Claude Opus 4.5 measured |
| Long context reasoning (AA-LCR) | 77.3% | Not measured | Only Claude Opus 4.5 measured |
| DTBench | 89.9% | Not measured | Only Claude Opus 4.5 measured |
| LMCA | 44.5% | Not measured | Only Claude Opus 4.5 measured |
| CL-bench | 21.1% | Not measured | Only Claude Opus 4.5 measured |
| Furniture assembly | 28.3% | Not measured | Only Claude Opus 4.5 measured |
| LMArena Text | 1451 | Not measured | Only Claude Opus 4.5 measured |
| LMArena Text: instruction following | 1478 | Not measured | Only Claude Opus 4.5 measured |
| LMArena Text: creative writing | 1445 | Not measured | Only Claude Opus 4.5 measured |
| LMArena Text: English | 1461 | Not measured | Only Claude Opus 4.5 measured |
| LMArena Text: non-English | 1438 | Not measured | Only Claude Opus 4.5 measured |
| LMArena Text: Chinese | 1470 | Not measured | Only Claude Opus 4.5 measured |
| LMArena Text: German | 1449 | Not measured | Only Claude Opus 4.5 measured |
| LMArena Text: Japanese | 1417 | Not measured | Only Claude Opus 4.5 measured |
| LMArena Text: Korean | 1424 | Not measured | Only Claude Opus 4.5 measured |
| LMArena Text: French | 1471 | Not measured | Only Claude Opus 4.5 measured |
| LMArena Text: Spanish | 1457 | Not measured | Only Claude Opus 4.5 measured |
| LMArena Text: Russian | 1447 | Not measured | Only Claude Opus 4.5 measured |
| LMArena Text: Polish | 1439 | Not measured | Only Claude Opus 4.5 measured |
| LMArena Text: multi-turn | 1466 | Not measured | Only Claude Opus 4.5 measured |
| LMArena Text: longer queries | 1479 | Not measured | Only Claude Opus 4.5 measured |
| LMArena Text: writing and language | 1452 | Not measured | Only Claude Opus 4.5 measured |
| LMArena Text: entertainment and media | 1434 | Not measured | Only Claude Opus 4.5 measured |
| LMArena Document | 1462 | Not measured | Only Claude Opus 4.5 measured |
| Neither model has a result on the other 20 boards here | |||
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | Claude Opus 4.5 | Codestral 2508 | 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
Codestral 2508 costs less
Repository review
50K input + 3K output tokens
Codestral 2508 costs less
Agent loop
200K input + 10K output tokens
Codestral 2508 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.
| Specification | Anthropic Claude Opus 4.5 | Mistral Codestral 2508 |
|---|---|---|
| Maker | Anthropic | Mistral AI |
| Weights | No public weights listed | No public weights listed |
| Released | November 24, 2025 | August 1, 2025 |
| Context window | 200K | 256K |
| Input $/Mtok | $5.00 | $0.30 |
| Output $/Mtok | $25.00 | $0.90 |
| Coding index | 44.0 | Not benchmarked |
| Independent measurements behind it | 3 | 0 |
| Cost per solved task | $1.37 | Not computable |
| Source | OpenRouter listing | OpenRouter listing |
Questions
Is Claude Opus 4.5 better than Codestral 2508 for coding?
Only Claude Opus 4.5 has a coding score, 44.0 on the Vibe Coding Index; Codestral 2508 has none, so the two cannot be ranked on coding. Codestral 2508 has the edge where output tokens cost 27.8x less, and where the context window is larger, 256K against 200K tokens.
Which is cheaper, Claude Opus 4.5 or Codestral 2508?
Claude Opus 4.5 costs $5.00 per million input tokens and $25.00 per million output tokens; Codestral 2508 costs $0.30 and $0.90. Cost per solved task is known for Claude Opus 4.5 only.
Which has the bigger context window, Claude Opus 4.5 or Codestral 2508?
Codestral 2508, with 256K tokens against 200K.
How many benchmarks is the Claude Opus 4.5 vs Codestral 2508 comparison based on?
6 benchmarks have a result for both models as of October 21, 2026. Claude Opus 4.5's coding index rests on 3 independent benchmarks and Codestral 2508's on 0. Where only one model has a result, the page says so instead of naming a winner.