# Specific Strength & Specific Modulus Calculator

Specific strength = σ/ρ and specific modulus = E/ρ (optional E). Enter strength in MPa and density in g/cm³; output in N·m/kg (also as kN·m/kg). The figure of merit for lightweight design — a material with high strength but high density (e.g. tungsten) often loses to a lighter alloy. Typical values: Ti-6Al-4V ≈ 210 kN·m/kg, Al 7075 ≈ 180, carbon steel ≈ 50–90, CFRP ≈ 1000+.

> Canonical page: https://elysiatools.com/en/tools/specific-strength-calculator

- **Category:** Math & Numbers

- **Keywords:** specific strength, strength-to-weight ratio, specific modulus, modulus-to-weight ratio, lightweight material, figure of merit, Ti-6Al-4V, aerospace material, materials science, N·m/kg

## Overview

Calculate specific strength from strength and density, and optionally calculate specific modulus from Young's modulus and density. Enter strength in MPa, density in g/cm³, and optional Young's modulus in MPa to receive results in N·m/kg and kN·m/kg.

## Inputs

- **Strength σ (MPa)** (number): Tensile or yield strength in MPa. E.g. Ti-6Al-4V ≈ 950, Al 7075-T6 ≈ 503, AISI 4340 ≈ 1280, carbon-fiber composite ≈ 1500.
- **Density ρ (g/cm³)** (number): Density in g/cm³. E.g. titanium ≈ 4.43, aluminum ≈ 2.81, steel ≈ 7.85, CFRP ≈ 1.5, tungsten ≈ 19.3.
- **Young's Modulus E (MPa, optional)** (number): Young's modulus in MPa. Optional — when given, specific modulus E/ρ is also reported. E.g. titanium ≈ 114000, aluminum ≈ 71700, steel ≈ 200000, CFRP ≈ 150000.
- **Decimal Places** (number)

## When to use

- Compare materials for lightweight structural design using strength-to-weight performance.
- Calculate specific strength from tensile or yield strength and material density.
- Calculate specific modulus when Young's modulus is also available.

## How it works

- Enter strength σ in MPa and density ρ in g/cm³.
- Optionally enter Young's modulus E in MPa to calculate specific modulus.
- The calculator computes specific strength as σ/ρ and specific modulus as E/ρ.
- Results are returned in N·m/kg, with specific strength also shown in kN·m/kg and specific modulus in MN·m/kg.

## Use cases

- Screen titanium, aluminum, steel, and composite materials for lightweight designs.
- Compare strength-to-weight ratios during preliminary aerospace or mechanical material selection.
- Evaluate both load-carrying strength and stiffness relative to density when modulus data is available.

## Frequently asked questions

### What is specific strength?

Specific strength is strength divided by density: σ/ρ. It indicates strength relative to material weight.

### What units should I enter?

Enter strength and optional Young's modulus in MPa, and density in g/cm³.

### Is Young's modulus required?

No. Strength and density are required; Young's modulus is optional and enables the specific modulus result.

### What does the calculator return?

It returns specific strength in N·m/kg and kN·m/kg. If Young's modulus is entered, it also returns specific modulus in N·m/kg and MN·m/kg.

### Can I control the displayed precision?

Yes. Set Decimal Places from 0 to 6; the default is 2.

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