# Safety Factor Calculator

Calculate the static safety factor n = σ_limit / σ_applied against yielding (σ_y) or ultimate tensile strength (σ_uts). Built-in typical strengths for carbon/alloy steel, aluminum, copper, austenitic stainless and titanium, plus a custom σ_limit option. Assessment: n<1 failure, 1≤n<1.5 marginal, n≥1.5 safe.

> Canonical page: https://elysiatools.com/en/tools/safety-factor-calculator

- **Category:** Math & Numbers

- **Keywords:** safety factor, factor of safety, n = sigma_limit/sigma, yield strength, ultimate tensile strength, allowable stress, static design, ductile design, mechanical design

## Overview

The Safety Factor Calculator computes the static safety factor using n = σ_limit / σ_applied. Choose a built-in material and strength limit, or enter a custom material limit, then receive a safety factor and assessment of failure, marginal, or safe.

## Inputs

- **Material** (select): Material preset supplies typical σ_y / σ_uts. Choose 'Custom' to enter σ_limit yourself.
- **Limit Type** (select): Use yield strength σ_y (ductile design, recommended) or ultimate tensile strength σ_uts.
- **Material Limit σ (MPa)** (number): Material limit σ (MPa). Required only when Material is 'Custom'; otherwise derived from the preset.
- **Applied Stress σ (MPa)** (number): Actual working stress in the part, in MPa.
- **Decimal Places** (number)

## When to use

- Check whether a part has sufficient static strength under a known applied stress.
- Compare a working stress with yield strength for ductile mechanical design.
- Evaluate a design against ultimate tensile strength using a selected material preset or custom limit.

## How it works

- Select a material preset or choose Custom and enter the material limit in MPa.
- Choose Yield or Ultimate as the limit type.
- Enter the applied working stress in MPa and select the desired number of decimal places.
- The tool calculates n = σ_limit / σ_applied and classifies the result as failure, marginal, or safe.

## Use cases

- Static strength checks for mechanical parts and assemblies.
- Preliminary ductile component design using yield strength.
- Comparing applied stress with material limits during design reviews.

## Frequently asked questions

### What is the safety factor formula?

The calculator uses n = σ_limit / σ_applied, where σ_limit is the selected material strength and σ_applied is the working stress.

### Which material options are available?

Presets are available for carbon steel, alloy steel, aluminum alloy, copper, austenitic stainless steel, and titanium alloy. A Custom option is also available.

### Should I use yield or ultimate strength?

Use Yield for ductile design, which is the recommended option in the tool, or Ultimate to calculate the factor against ultimate tensile strength.

### How is the result classified?

A factor below 1 is failure, 1 to below 1.5 is marginal, and 1.5 or higher is safe.

### When is a custom material limit required?

Enter a custom material limit in MPa only when the Material selection is Custom. Preset materials supply their own typical strength values.

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