Yi-Lightning 1.5B: pricing, context window and benchmarks
Yi-Lightning 1.5B is a small open-weight model from 01.AI. It offers a 4,096-token context window, costs $0.54 per million input tokens and $2.52 per million output tokens, and averages 50.0 across the index's benchmark suite.
Pricing
Yi-Lightning 1.5B costs $0.54 per million input tokens and $2.52 per million output tokens. A blended 3:1 input-to-output mix works out to about $1.04 per million tokens. Cached input is listed at $0.08 per million tokens.
| Item | Price | Notes |
|---|---|---|
| Input | $0.54 | per 1M tokens |
| Output | $2.52 | per 1M tokens |
| Cached input | $0.08 | per 1M tokens |
| Blended 3:1 | $1.04 | estimate per 1M tokens |
| 1M in + 1M out | $3.06 | estimate |
Benchmarks
Scores below are modelled estimates on a 0–100 scale. Use them to compare relative position, not as official vendor results.
| Benchmark | Score | Rank | Percentile | Relative |
|---|---|---|---|---|
| MMLU-Pro | 58.2 | 549 | 9th | |
| GPQA Diamond | 48.1 | 538 | 10th | |
| SWE-bench Verified | 35.8 | 547 | 9th | |
| HumanEval | 51.0 | 567 | 6th | |
| MATH-500 | 49.2 | 561 | 7th | |
| AIME 2025 | 35.0 | 570 | 5th | |
| LiveCodeBench | 35.8 | 566 | 6th | |
| IFEval | 62.0 | 554 | 8th | |
| TruthfulQA | 56.6 | 560 | 7th | |
| HellaSwag | 69.7 | 539 | 10th | |
| MMMU | 48.4 | 560 | 7th | |
| Arena Elo | 1209.1 | 544 | 9th |
What Yi-Lightning 1.5B is good for
Yi-Lightning 1.5B is a small model. That makes it a good fit for classification, extraction, routing, summarization and other high-volume jobs where latency and cost dominate. It is not the right pick for open-ended frontier reasoning, but at $0.54 per million input tokens it can handle a large share of production traffic.
Strengths
- Input price of $0.54 per million tokens is at or below the index median.
- Open weights make self-hosting, fine-tuning and data-residency review possible.
Trade-offs
- Context window of 4,096 tokens is small for long-document work.
- Average benchmark score is below the index median; test it on your own task.
- Less reliable on open-ended reasoning and complex multi-step instructions.
How it compares
| Model | Provider | Context | Input / 1M | Avg score |
|---|---|---|---|---|
| Llama 3.1 Cerebras 1.5B | Cerebras | 4096 | $0.48 | 50.2 |
| Command R+ 1.5B | Cohere | 32768 | $0.51 | 50.0 |
| Llama 3.3 Groq 1.5B | Groq | 4096 | $0.46 | 50.0 |
| Yi-Lightning 1.5B | 01.AI | 4096 | $0.54 | 50.0 |
| Codestral 1.5B | Mistral AI | 8192 | $0.52 | 49.9 |
| Molmo 8B | Allen Institute for AI | 32768 | $0.44 | 49.9 |
FAQ
How much does Yi-Lightning 1.5B cost?
Yi-Lightning 1.5B is listed at $0.54 per million input tokens and $2.52 per million output tokens. Cached input is $0.080 per million tokens. A blended 3:1 input-to-output mix is about $1.04 per million tokens.
What is the context window of Yi-Lightning 1.5B?
Yi-Lightning 1.5B has a context window of 4,096 tokens and can emit up to 4,096 output tokens per request in this index.
Is Yi-Lightning 1.5B open weights?
Yes. Yi-Lightning 1.5B is listed as an open-weight model under a open weights licence.
How does Yi-Lightning 1.5B score on benchmarks?
Yi-Lightning 1.5B averages 50.0 across the scored benchmarks in this index, ranking #556 of 600 models. Its strongest relative result is Arena Elo at 1209.1.
What is Yi-Lightning 1.5B best for?
Yi-Lightning 1.5B is a small model. That makes it a good fit for classification, extraction, routing, summarization and other high-volume jobs where latency and cost dominate. It is not the right pick for open-ended frontier reasoning, but at $0.54 per million input tokens it can handle a large share of production traffic.