AI21 LabsJamba 1.5 Large
Jamba 1.5 Large is an AI21 Labs open-weights model, released 22 Aug 2024. Its best configuration ranks #603 of 785 on the BenchLeader Index at 42.2 ±4.8, in the lower half. The ± is the point: 306 other configurations score within that range, so they and this one cannot be told apart on quality alone — price and speed are what separate them. It scores highest in human preference (44) and lowest in knowledge (33). At $3.50 per million tokens blended it is among the most expensive ranked models. Last measured 22 Oct 2026.
- Blended price
- $3.50/M
- $2.00 in · $8.00 out
- Output speed
- –
- First answer
- –
- Context
- 256k
- Full answer
- –
- Cost per run
- –
- Released
- 22 Aug 2024
- Overall index42
- Reasoning42
- Coding42
- Maths41
- Knowledge33
- Human preference44
- Composite36
Versions
AI21 Labs has shipped 5 models under this name. Each is ranked on its own results; a newer version often has fewer results so far, which holds its index nearer the average until more arrive.
| Model | Released | Index | Rank |
|---|---|---|---|
| Jamba 1.7 Large | 7 Jul 2025 | 41.3 | #634 |
| Jamba Large | 3 Jul 2025 | – | – |
| Jamba 1.5 Largethis page | 22 Aug 2024 | 42.2 | #603 |
| Jamba Large 1.6 | – | 26.0 | #784 |
| Jamba Large 1.7 | – | – | – |
How its index has moved
9 Sept 2026 to 21 Oct 2026The index is recomputed from scratch every day, so a line moves when a new benchmark result lands, when a publisher revises a score, or when the models it is normalised against change. Early movement usually means the score is still settling.
Benchmark results
See all LLM benchmarks. One column per reasoning effort. Rank is among every configuration of every model on that benchmark. Hover a score for the run it came from.
Reasoning
| Benchmark | not stated | Source | Trend |
|---|---|---|---|
| Arena Hard Prompts | 1284#269 | Arena (LMArena) | |
| GPQA Diamond (AA)not in index | 42.7%#464 | Artificial Analysis | |
| Humanity's Last Exam (AA)not in index | 4.1%#546 | Artificial Analysis |
Coding
| Benchmark | not stated | Source | Trend |
|---|---|---|---|
| Arena Coding | 1312#269 | Arena (LMArena) |
Maths
| Benchmark | not stated | Source | Trend |
|---|---|---|---|
| Arena Maths | 1245#271 | Arena (LMArena) |
Knowledge
Instruction following
| Benchmark | not stated | Source | Trend |
|---|---|---|---|
| Arena Instruction Followingnot in index | 1267#269 | Arena (LMArena) |
Human preference
| Benchmark | not stated | Source | Trend |
|---|---|---|---|
| Arena Text | 1290#262 | Arena (LMArena) | |
| Arena Creative Writingnot in index | 1261#257 | Arena (LMArena) | |
| Arena Multi-turnnot in index | 1266#269 | Arena (LMArena) | |
| Arena Longer Queriesnot in index | 1261#286 | Arena (LMArena) |
Composite
| Benchmark | not stated | Source | Trend |
|---|---|---|---|
| AA Intelligence Index v4.3.2 | 6.0#545 | Artificial Analysis |
What a task costs
Estimates from list price, output speed and time to first answer for the best configuration. “With caching” assumes three-quarters of the input is served from the prompt cache. Reasoning tokens are not modelled.
| Workload | Tokens in / out | Cost | With caching | Time |
|---|---|---|---|---|
| Chat reply | 400 / 300 | $0.0032 | – | – |
| Summarize a 30-page report | 12,000 / 600 | $0.029 | – | – |
| Code edit | 6,000 / 1,500 | $0.024 | – | – |
| Agentic coding session | 60,000 / 4,000 | $0.152 | – | – |
| Structured extraction | 2,000 / 200 | $0.0056 | – | – |
More from AI21 Labs
See also
Questions people ask
- What are Jamba 1.5 Large's benchmark scores?
- As of 25 Oct 2026, Jamba 1.5 Large scores 42.2 ±4.8 on the BenchLeader Index, strongest in human preference (44) and weakest in knowledge (33). That rests on 9 independent benchmark results, and every score on this page links to its publisher.
- How does Jamba 1.5 Large rank?
- Jamba 1.5 Large is #603 of 785 ranked configurations on 25 Oct 2026. 306 other configurations score within its margin, so the exact position matters less than the band. The leader is Claude Opus 5.5 (max effort) at 72.6.
- How much does Jamba 1.5 Large cost per 1M tokens?
- As of 25 Oct 2026, Jamba 1.5 Large costs $2.00 per 1M input tokens and $8.00 per 1M output tokens, $3.50 blended (three input tokens per output token).
- When was Jamba 1.5 Large released?
- AI21 Labs released Jamba 1.5 Large on 22 Aug 2024.
Data as of 25 Oct 2026. Compare with another model.
Cite as: BenchLeader, “Jamba 1.5 Large: benchmarks, pricing, speed and rank”, data as of 25 Oct 2026, https://www.benchleader.com/models/jamba-1-5-large.