LongCat Flash Chat — Hardware Requirements & GPU Compatibility
Chat
LongCat Flash Chat is a 561.9B-parameter open language model from Meituan in the LongCat family. It supports a context window of up to 131,072 tokens. At BF16 it needs about 1236.10 GB of VRAM — see which GPUs and Macs can run it below.
LongCat Flash Chat runs on a multi-GPU server
BF16 needs ~1.2 TB · about 8× B200 192 GB
MIT
Not set up for it?
Reference GPU · RTX 4090 24 GB
Estimates, ±20% · how we estimate
Run LongCat Flash Chat
One recommended way. Every other method, OS and quant is in the step-by-step guide.
Recommended
vllm serve meituan-longcat/LongCat-Flash-Chat --max-model-len 16384 --tensor-parallel-size 8Size the nodes from the table above
Download: Weights on Hugging Face
Other ways
each opens step-by-stepRun in cloud
Rent 8× B200 node · BF16
- Estimated hourly price
- ~$47.84/hr
- est., whole server
- GPUs
- 8 GPUs
- 1.5 TB of VRAM
How Much VRAM Does LongCat Flash Chat Need?
Select a quantization level; the listed hardware adheres to it.
| Quantization | VRAM | +32K | Runs on | |
|---|---|---|---|---|
| 1236.1 GB | 1254.2 GB | 16-bit · bfloat — Brain floating point 16 — preferred for training | Runs on 8× B200 192 GB |
Selected BF16
Brain floating point 161244.5GBat 16K context
- Weights
- 1234.6 GB
- KV cache
- 9.7 GB
- Overhead
- 0.3 GB
Server-class: ~1.2 TB at 16K context · about 8× B200 192 GB
Which Hardware Can Run LongCat Flash Chat?
BF16 · 1236.1 GBLongCat Flash Chat (BF16) requires 1236.1 GB of VRAM to load the model weights. For comfortable inference with headroom for KV cache and system overhead, 1607+ GB is recommended. No consumer GPU has enough memory.
Needs server-class hardware
LongCat Flash Chat runs on a multi-GPU server · BF16 needs ~1.2 TB
| Hardware | Quant | Memory | Context | Hardware page | |
|---|---|---|---|---|---|
| 8× B200 192 GB · 1.5 TB | BF16 | 1244.5 GB | 128K ctx | B200 → | BF16 · 1244.5 GB · 128K ctx |
By VRAM tier · typical GPUs and Macs at BF16
Consumer GPUs (up to 32 GB) and Macs up to 512 GB: too small for this model (needs ≥ 1.2 TB)8 GB tier →12 GB tier →16 GB tier →24 GB tier →Macs →
How good is LongCat Flash Chat?
llmrun Score blends public benchmark boards into one number; 100 = the average open model.
Not enough data yet for an llmrun Score.
A Score needs results on enough independent boards. How the Composite Score is built
Benchmarks
Here are all 2 boards that have results for this model, sorted by their weight in the llmrun Score; badges show who ran the test.
- LMArena Text
LMArena · Oct 2026Arena
Arena1400.6
#48/187 open
- MMLU-Pro
TIGER-LabIndependent
Independent82.7%
#16/145 open
Similar models
2| Model | Score | VRAM | tok/s | Why it is similar |
|---|---|---|---|---|
| NVIDIA Nemotron 3 Ultra 550B A55B BF16NVIDIA | 109.9 | 378.4 GB | —needs > 24 GB | same size |
| Ling 3.1 FlashInclusion AI | — | 344.9 GB | —needs > 24 GB | same size |
Specifications
- Publisher
- Meituan
- Family
- LongCat
- Parameters
- 561.9B
- Active parameters
- 29.2B per token
- Architecture
- LongcatFlashForCausalLM
- Context Length
- 131,072 tokens
- Vocabulary Size
- 131,072
- Release Date
- 2025-08-29
- License
- MIT
Frequently Asked Questions
How much VRAM does LongCat Flash Chat need?
LongCat Flash Chat requires 1236.1 GB of VRAM at BF16.
VRAM = Weights + KV Cache + Overhead
Weights = 561.9B × 16 bits ÷ 8 = 1123.7 GB
KV Cache + Overhead ≈ 112.4 GB (at 2K context + ~0.3 GB framework)
Fit ratings and hardware model lists check this model with room for a 16K-token context, which needs a little more memory.
VRAM usage by quantization
Can NVIDIA GeForce RTX 5090 run LongCat Flash Chat?
No — LongCat Flash Chat requires at least 1236.1 GB at BF16, which exceeds the NVIDIA GeForce RTX 5090's 32 GB of VRAM.
Can I run LongCat Flash Chat on a Mac?
LongCat Flash Chat requires at least 1236.1 GB at BF16. None of the 146 Macs we list has that much usable memory (the largest has 508.5 GB after macOS overhead).
Can I run LongCat Flash Chat locally?
Yes — LongCat Flash Chat can run locally on consumer hardware. Popular tools include Ollama, LM Studio, and llama.cpp.
What's the download size of LongCat Flash Chat?
At BF16, the download is about 1123.73 GB.
Which GPUs can run LongCat Flash Chat?
No single consumer GPU has enough VRAM to run LongCat Flash Chat at BF16 (1236.1 GB). Multi-GPU or professional hardware is required.
Which devices can run LongCat Flash Chat?
LongCat Flash Chat requires at least 1236.1 GB at BF16, which exceeds the usable memory of every unified-memory device we list (the largest has 508.5 GB).