7+ Main precision formats used in AI:

Precision is very important in AI as it shapes how accurate and efficient models are. It controls how finely numbers are represented, approximating real-world values with formats like fixed-point and floating-point. A recent BF16 → FP16 study renewed attention to precision impact.
Here are the main precision types used in AI, from full precision for training to ultra-low precision for inference:

1. FP32 (Float32):
Standard full-precision float used in most training: 1 sign bit, 8 exponent bits, 23 mantissa bits. Default for backward-compatible training and baseline numerical stability

2. FP16 (Float16) → https://arxiv.org/abs/2305.10947v6
Half-precision float. It balances accuracy and efficiency. 1 sign bit, 5 exponent bits, 10 mantissa bits. Common on NVIDIA Tensor Cores and mixed-precision setups. There’s now a new wave of using it in reinforcement learning: https://www.turingpost.com/p/fp16

3. BF16 (BFloat16) → https://cloud.google.com/blog/products/ai-machine-learning/bfloat16-the-secret-to-high-performance-on-cloud-tpus
Same dynamic range as FP32 but fewer mantissa bits: 1 sign bit, 8 exponent bits (same as FP32), 7 mantissa bits. It was developed by the research group Google Brain as part of their AI/ML infrastructure work at Google. Preferred on TPUs and modern GPUs

4. FP8 (E4M3 / E5M2) → https://proceedings.neurips.cc/paper_files/paper/2018/file/335d3d1cd7ef05ec77714a215134914c-Paper.pdf
Emerging standard for training and inference on NVIDIA Hopper (H100) and Blackwell (B200) tensor cores and AMD MI300. Also supported in NVIDIA’s Transformer Engine: https://developer.nvidia.com/blog/floating-point-8-an-introduction-to-efficient-lower-precision-ai-training/
E4M3 = 4 exponent, 3 mantissa bits
E5M2 = 5 exponent, 2 mantissa bits

Read further below ⬇️
If you like this, also subscribe to the Turing post: https://www.turingpost.com/subscribe