Seed 2.1 Turbo vs Claude Sonnet 5.5
Seed 2.1 Turbo costs 4.0x less per output token than Claude Sonnet 5.5 ($2.50 vs $10.00 per million). Updated October 23, 2026; no benchmark has tested both models yet.
Seed 2.1 TurboByteDance Seed
- Coding
- No data
- Overall
- No data
- Output $/M
- $2.50
Claude Sonnet 5.5Anthropic
- Coding
- 87.3
- Overall
- 82.8
- Output $/M
- $10.00
vs $2.50 vs $10.00 per 1M output tokens. Seed 2.1 Turbo is 4.0x cheaper.
Seed 2.1 Turbo or Claude Sonnet 5.5: which to pick
Only Claude Sonnet 5.5 has a coding score, 87.3 on the Vibe Coding Index; Seed 2.1 Turbo has none, so the two cannot be ranked on coding.
Pick Seed 2.1 Turbo for output tokens 4.0x cheaper ($2.50 vs $10.00 per million).
Model ASeed 2.1 TurboByteDance SeedNot benchmarkedNo coding benchmarkNo cost per solved taskModel BClaude Sonnet 5.5Anthropic87.3/1005 independent benchmarksNo cost per solved task
No benchmark has tested both yet. Seed 2.1 Turbo has none yet; Claude Sonnet 5.5 on LiveBench coding, LMArena WebDev and Terminal-Bench 4 (Vals AI). Compare them on price and context instead.
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 Sonnet 5.5 has a coding score, so no call is made.
One side not measured
Intelligence
AA Intelligence Index
No call
Only Claude Sonnet 5.5 has a AA Intelligence Index result, 56.0.
Directional only
Web design
Design Arena: websites
No call
Only Claude Sonnet 5.5 has a Design Arena: websites result, 1327.
Directional only
General
Vals Index
No call
Only Claude Sonnet 5.5 has a Vals Index result, 70.8%.
Directional only
Long documents
Listed context window
Claude Sonnet 5.5
Claude Sonnet 5.5 takes 1M tokens against 262K.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
Seed 2.1 Turbo
Seed 2.1 Turbo $0.0018, Claude Sonnet 5.5 $0.0070 per turn.
List prices
At a glance
- Coding index
- Seed 2.1 Turbo not benchmarked, Claude Sonnet 5.5 87.3 from 5 benchmarks.
- Widest category
- None yet: no category has been tested on both models.
- Widest single gap
- None yet: no benchmark has tested both models.
- Output price
- Seed 2.1 Turbo $2.50 against Claude Sonnet 5.5 $10.00 per million output tokens, 4.0x apart.
- Context window
- Seed 2.1 Turbo takes 262K tokens, Claude Sonnet 5.5 1M.
Benchmark by benchmark
Every board either model has a result on, a category to a fold; bars are each result on a 0 to 100 scale. Only one model is measured on each, so no row names a leader.
CodingDirectional onlySix of these boards feed the Vibe Coding Index21 boards measured
| Benchmark | Seed 2.1 Turbo | Claude Sonnet 5.5 | Leader |
|---|---|---|---|
| LiveBench coding | Not measured | 94.7% | Only Claude Sonnet 5.5 measured |
| LMArena WebDev | Not measured | 1767 | Only Claude Sonnet 5.5 measured |
| Terminal-Bench 4 (Vals AI) | Not measured | 64.1% | Only Claude Sonnet 5.5 measured |
| Vibe Code Bench (Vals AI) | Not measured | 92.4% | Only Claude Sonnet 5.5 measured |
| Code migration (Vals AI) | Not measured | 69.8% | Only Claude Sonnet 5.5 measured |
| ProgramBench (Vals AI) | Not measured | 6.5% | Only Claude Sonnet 5.5 measured |
| IOI (Vals AI) | Not measured | 83.1% | Only Claude Sonnet 5.5 measured |
| Terminal-Bench 2.1 (Vals AI) | Not measured | 83.2% | Only Claude Sonnet 5.5 measured |
| SWE-bench Multimodal (Vals AI) | Not measured | 58.3% | Only Claude Sonnet 5.5 measured |
| CyberBench (Vals AI) | Not measured | 59.6% | Only Claude Sonnet 5.5 measured |
| SciCode | Not measured | 61.0% | Only Claude Sonnet 5.5 measured |
| FrontierCode | Not measured | 52.1% | Only Claude Sonnet 5.5 measured |
| FrontierSWE | Not measured | 61.9% | Only Claude Sonnet 5.5 measured |
| ALE-Bench | Not measured | 1819.1 | Only Claude Sonnet 5.5 measured |
| LMArena Text: coding | Not measured | 1510 | Only Claude Sonnet 5.5 measured |
| LMArena Text: software and IT | Not measured | 1501 | Only Claude Sonnet 5.5 measured |
| LMArena WebDev: React | Not measured | 1815 | Only Claude Sonnet 5.5 measured |
| LMArena WebDev: HTML | Not measured | 1738 | Only Claude Sonnet 5.5 measured |
| LMArena WebDev: from an image | Not measured | 1737 | Only Claude Sonnet 5.5 measured |
| SciCode | Not measured | 13.8% | Only Claude Sonnet 5.5 measured |
| SWE-Bench Pro V2 | Not measured | 95.8% | Only Claude Sonnet 5.5 measured |
| Neither model has a result on the other 22 boards here | |||
IntelligenceDirectional onlyPublic boards, shown as published, kept out of the index2 boards measured
| Benchmark | Seed 2.1 Turbo | Claude Sonnet 5.5 | Leader |
|---|---|---|---|
| AA Intelligence Index | Not measured | 56.0 | Only Claude Sonnet 5.5 measured |
| Epoch Capabilities Index | Not measured | 166.2 | Only Claude Sonnet 5.5 measured |
Agentic workDirectional onlyPublic boards, shown as published, kept out of the index18 boards measured
| Benchmark | Seed 2.1 Turbo | Claude Sonnet 5.5 | Leader |
|---|---|---|---|
| Design Arena: agents building web apps | Not measured | 1305 | Only Claude Sonnet 5.5 measured |
| Design Arena: agents building mobile apps | Not measured | 1262 | Only Claude Sonnet 5.5 measured |
| Design Arena: spreadsheets | Not measured | 1272 | Only Claude Sonnet 5.5 measured |
| LiveBench research | Not measured | 83.6% | Only Claude Sonnet 5.5 measured |
| LiveBench browser | Not measured | 84.0% | Only Claude Sonnet 5.5 measured |
| LiveBench long agentic | Not measured | 78.8% | Only Claude Sonnet 5.5 measured |
| SREBench (Vals AI) | Not measured | 30.1% | Only Claude Sonnet 5.5 measured |
| Finance Agent (Vals AI) | Not measured | 58.1% | Only Claude Sonnet 5.5 measured |
| Tax Agent Bench (Vals AI) | Not measured | 42.0% | Only Claude Sonnet 5.5 measured |
| Legal Research Bench (Vals AI) | Not measured | 48.1% | Only Claude Sonnet 5.5 measured |
| Harvey's Legal Agent Benchmark (Vals AI) | Not measured | 10.4% | Only Claude Sonnet 5.5 measured |
| Excel Modeling Benchmark (Vals AI) | Not measured | 75.7% | Only Claude Sonnet 5.5 measured |
| BioMysteryBench (Vals AI) | Not measured | 81.1% | Only Claude Sonnet 5.5 measured |
| Terminal-Bench-Science (Vals AI) | Not measured | 47.1% | Only Claude Sonnet 5.5 measured |
| Vals Science Index | Not measured | 59.1% | Only Claude Sonnet 5.5 measured |
| APEX-Agents | Not measured | 75.5% | Only Claude Sonnet 5.5 measured |
| SpireClimb | Not measured | 1.3% | Only Claude Sonnet 5.5 measured |
| Vending-Bench 2 | Not measured | $11,165 | Only Claude Sonnet 5.5 measured |
| Neither model has a result on the other 24 boards here | |||
ReasoningDirectional onlyPublic boards, shown as published, kept out of the index12 boards measured
| Benchmark | Seed 2.1 Turbo | Claude Sonnet 5.5 | Leader |
|---|---|---|---|
| LiveBench reasoning | Not measured | 91.6% | Only Claude Sonnet 5.5 measured |
| MysteryMechanism (Vals AI) | Not measured | 49.1% | Only Claude Sonnet 5.5 measured |
| Humanity's Last Exam (Artificial Analysis run) | Not measured | 55.0% | Only Claude Sonnet 5.5 measured |
| GPQA Diamond (Epoch AI run) | Not measured | 95.6% | Only Claude Sonnet 5.5 measured |
| Chess puzzles | Not measured | 59.0% | Only Claude Sonnet 5.5 measured |
| Mystery game puzzles | Not measured | 65.0% | Only Claude Sonnet 5.5 measured |
| LMArena Text: hard prompts | Not measured | 1493 | Only Claude Sonnet 5.5 measured |
| LMArena Text: expert | Not measured | 1530 | Only Claude Sonnet 5.5 measured |
| LMArena Text: hard prompts in English | Not measured | 1502 | Only Claude Sonnet 5.5 measured |
| LMArena Vision: diagrams | Not measured | 1329 | Only Claude Sonnet 5.5 measured |
| LMArena Vision: homework | Not measured | 1331 | Only Claude Sonnet 5.5 measured |
| Humanity's Last Exam (Scale run) | Not measured | 37.5% | Only Claude Sonnet 5.5 measured |
| Neither model has a result on the other 11 boards here | |||
MathDirectional onlyPublic boards, shown as published, kept out of the index6 boards measured
| Benchmark | Seed 2.1 Turbo | Claude Sonnet 5.5 | Leader |
|---|---|---|---|
| OTIS Mock AIME | Not measured | 100.0% | Only Claude Sonnet 5.5 measured |
| FrontierMath, tiers 1 to 3 | Not measured | 88.8% | Only Claude Sonnet 5.5 measured |
| FrontierMath, tier 4 | Not measured | 80.5% | Only Claude Sonnet 5.5 measured |
| ProofBench | Not measured | 100.0% | Only Claude Sonnet 5.5 measured |
| LMArena Text: math | Not measured | 1498 | Only Claude Sonnet 5.5 measured |
| LMArena Text: mathematical work | Not measured | 1511 | Only Claude Sonnet 5.5 measured |
| Neither model has a result on the other 8 boards here | |||
KnowledgeDirectional onlyPublic boards, shown as published, kept out of the index6 boards measured
| Benchmark | Seed 2.1 Turbo | Claude Sonnet 5.5 | Leader |
|---|---|---|---|
| MedCode (Vals AI) | Not measured | 52.9% | Only Claude Sonnet 5.5 measured |
| SimpleQA Verified | Not measured | 46.5% | Only Claude Sonnet 5.5 measured |
| LMArena Text: science | Not measured | 1486 | Only Claude Sonnet 5.5 measured |
| LMArena Text: medicine and healthcare | Not measured | 1467 | Only Claude Sonnet 5.5 measured |
| LMArena Text: legal and government | Not measured | 1480 | Only Claude Sonnet 5.5 measured |
| LMArena Text: business and finance | Not measured | 1468 | Only Claude Sonnet 5.5 measured |
| Neither model has a result on the other 14 boards here | |||
Web designDirectional onlyPublic boards, shown as published, kept out of the index7 boards measured
| Benchmark | Seed 2.1 Turbo | Claude Sonnet 5.5 | Leader |
|---|---|---|---|
| Design Arena: websites | Not measured | 1327 | Only Claude Sonnet 5.5 measured |
| Design Arena: UI components | Not measured | 1369 | Only Claude Sonnet 5.5 measured |
| Design Arena: game dev | Not measured | 1470 | Only Claude Sonnet 5.5 measured |
| Design Arena: data viz | Not measured | 1382 | Only Claude Sonnet 5.5 measured |
| Design Arena: 3D | Not measured | 1400 | Only Claude Sonnet 5.5 measured |
| Design Arena: all code categories | Not measured | 1357 | Only Claude Sonnet 5.5 measured |
| LiveBench design | Not measured | 85.0% | Only Claude Sonnet 5.5 measured |
| Neither model has a result on the other 2 boards here | |||
GeneralDirectional onlyPublic boards, shown as published, kept out of the index27 boards measured
| Benchmark | Seed 2.1 Turbo | Claude Sonnet 5.5 | Leader |
|---|---|---|---|
| Vals Index | Not measured | 70.8% | Only Claude Sonnet 5.5 measured |
| LiveBench data analysis | Not measured | 59.5% | Only Claude Sonnet 5.5 measured |
| Public Benefits Bench (Vals AI) | Not measured | 67.2% | Only Claude Sonnet 5.5 measured |
| SAGE (Vals AI) | Not measured | 51.8% | Only Claude Sonnet 5.5 measured |
| MedScribe (Vals AI) | Not measured | 91.1% | Only Claude Sonnet 5.5 measured |
| Long context reasoning (AA-LCR) | Not measured | 82.7% | Only Claude Sonnet 5.5 measured |
| DTBench | Not measured | 97.3% | Only Claude Sonnet 5.5 measured |
| LMCA | Not measured | 68.3% | Only Claude Sonnet 5.5 measured |
| Furniture assembly | Not measured | 75.0% | Only Claude Sonnet 5.5 measured |
| LMArena Text | Not measured | 1473 | Only Claude Sonnet 5.5 measured |
| LMArena Text: instruction following | Not measured | 1491 | Only Claude Sonnet 5.5 measured |
| LMArena Text: creative writing | Not measured | 1468 | Only Claude Sonnet 5.5 measured |
| LMArena Vision | Not measured | 1287 | Only Claude Sonnet 5.5 measured |
| LMArena Text: English | Not measured | 1486 | Only Claude Sonnet 5.5 measured |
| LMArena Text: non-English | Not measured | 1456 | Only Claude Sonnet 5.5 measured |
| LMArena Text: Chinese | Not measured | 1535 | Only Claude Sonnet 5.5 measured |
| LMArena Text: Japanese | Not measured | 1460 | Only Claude Sonnet 5.5 measured |
| LMArena Text: French | Not measured | 1495 | Only Claude Sonnet 5.5 measured |
| LMArena Text: Spanish | Not measured | 1446 | Only Claude Sonnet 5.5 measured |
| LMArena Text: Russian | Not measured | 1458 | Only Claude Sonnet 5.5 measured |
| LMArena Text: multi-turn | Not measured | 1465 | Only Claude Sonnet 5.5 measured |
| LMArena Text: longer queries | Not measured | 1495 | Only Claude Sonnet 5.5 measured |
| LMArena Text: writing and language | Not measured | 1476 | Only Claude Sonnet 5.5 measured |
| LMArena Text: entertainment and media | Not measured | 1462 | Only Claude Sonnet 5.5 measured |
| LMArena Vision: English | Not measured | 1289 | Only Claude Sonnet 5.5 measured |
| LMArena Vision: reading text | Not measured | 1297 | Only Claude Sonnet 5.5 measured |
| LMArena Vision: creative writing | Not measured | 1242 | Only Claude Sonnet 5.5 measured |
| Neither model has a result on the other 21 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
Seed 2.1 Turbo$0.0018Fits in one request
Claude Sonnet 5.5$0.0070Fits in one request
Seed 2.1 Turbo costs less
Repository review
50K input + 3K output tokens
Seed 2.1 Turbo$0.033Fits in one request
Claude Sonnet 5.5$0.130Fits in one request
Seed 2.1 Turbo costs less
Agent loop
200K input + 10K output tokens
Seed 2.1 Turbo$0.125Fits in one request
Claude Sonnet 5.5$0.500Fits in one request
Seed 2.1 Turbo 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 | ByteDance Seed Seed 2.1 Turbo | Anthropic Claude Sonnet 5.5 |
|---|---|---|
| Maker | ByteDance Seed | Anthropic |
| Weights | No public weights listed | No public weights listed |
| Released | August 12, 2026 | September 28, 2026 |
| Context window | 262K | 1M |
| Input $/Mtok | $0.50 | $2.00 |
| Output $/Mtok | $2.50 | $10.00 |
| Coding index | Not benchmarked | 87.3 |
| Independent measurements behind it | 0 | 5 |
| Cost per solved task | Not computable | Not computable |
| Source | OpenRouter listing | OpenRouter listing |
Questions
Is Seed 2.1 Turbo better than Claude Sonnet 5.5 for coding?
Only Claude Sonnet 5.5 has a coding score, 87.3 on the Vibe Coding Index; Seed 2.1 Turbo has none, so the two cannot be ranked on coding. Pick Seed 2.1 Turbo for output tokens 4.0x cheaper ($2.50 vs $10.00 per million).
Which is cheaper, Seed 2.1 Turbo or Claude Sonnet 5.5?
Seed 2.1 Turbo costs $0.50 per million input tokens and $2.50 per million output tokens; Claude Sonnet 5.5 costs $2.00 and $10.00. Cost per solved task is known for neither of them.
Which has the bigger context window, Seed 2.1 Turbo or Claude Sonnet 5.5?
Claude Sonnet 5.5, with 1M tokens against 262K.
Has any benchmark tested both Seed 2.1 Turbo and Claude Sonnet 5.5?
No benchmark has tested both yet. Seed 2.1 Turbo has none yet; Claude Sonnet 5.5 on LiveBench coding, LMArena WebDev and Terminal-Bench 4 (Vals AI). Compare them on price and context instead. Data as of October 23, 2026.