# What is Batch Size? Definition & Technical Mechanics

> **Source:** [SPIDITS AI AI Glossary](https://spidits.com/ai-glossary)  
> **Category:** Model Training  
> **Canonical Citation:** [https://spidits.com/ai-glossary/batch-size](https://spidits.com/ai-glossary/batch-size)

## Definition
Batch Size is a model training hyperparameter defining the number of training examples processed in a single forward and backward pass before the model's internal parameter weights are updated.

## Architectural Mechanics & Deep Dive
Batch size is a critical training hyperparameter that defines the number of training samples processed in one forward and backward pass before the model's internal weights are updated. A smaller batch size provides a noisier gradient estimate, which can help escape local minima, but is less computationally efficient. A larger batch size offers smoother gradients and better utilizes parallel GPU processing power but can sometimes result in poorer generalization.

## Industry Applications & Real-World Use Cases
Gradient updates, training optimization, and GPU memory allocation.

## Frequently Asked Questions

### What is the tradeoff of using a large batch size?
Large batch sizes utilize GPU parallel processing efficiently, accelerating epoch training speeds. However, they consume more VRAM and can lead to poorer generalization performance compared to smaller batches.

### What is the difference between batch and epoch?
A batch size is the subset of data processed before weights are updated. An epoch is completed when the model has processed the entire dataset exactly once.

## Related Terminology
- [epoch](https://spidits.com/ai-glossary/epoch)
- [gpu](https://spidits.com/ai-glossary/gpu)
- [gradient-descent](https://spidits.com/ai-glossary/gradient-descent)
- [hyperparameter](https://spidits.com/ai-glossary/hyperparameter)

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*From the SPIDITS AI Knowledge Base (336+ terms indexed). Explore full technical definitions: [https://spidits.com/ai-glossary](https://spidits.com/ai-glossary)*