Understanding the coefficient of friction can help greatly when selecting materials for mechanical design, whether you’re working with metals, plastics, or composites. Engineers often reference a friction coefficient chart or a coefficient of friction table to determine how different surfaces interact under load. For example, the coefficient of friction steel on steel can vary depending on surface finish and lubrication, making accurate data critical in design calculations.
This guide provides a practical overview of friction values for common materials, along with a calculator to help simplify your project planning.
Friction Force Calculator
Coefficient of Friction Table
Common Material Combinations (Dry Conditions at Room Temperature)
| Material Combination | Static (μₛ) | Kinetic (μₖ) | Notes |
|---|---|---|---|
| Rubber on Dry Concrete | — | 0.6-0.85 | Tire applications, high grip |
| Rubber on Wet Concrete | — | 0.45-0.75 | Reduced friction when wet |
| Rubber on Dry Asphalt | 0.9 | 0.5-0.8 | Car tires, temperature dependent |
| Rubber on Wet Asphalt | — | 0.25-0.75 | Significant reduction when wet |
| Rubber on Rubber | 1.16 | — | Very high static friction |
| Steel on Steel (Clean) | 0.5-0.8 | 0.42 | Dry, clean surfaces |
| Steel on Steel (Grease) | 0.16 | — | Lubricated surfaces |
| Steel on Steel (Oil) | 0.11-0.23 | 0.081-0.084 | Various oil types (castor, mineral, lard) |
| Aluminum on Aluminum (Clean) | 1.05-1.35 | 0.4 | High friction when clean |
| Aluminum on Aluminum (Lubricated) | 0.3 | — | Significantly reduced with lubrication |
| Aluminum on Mild Steel | 0.61 | 0.47 | Common engineering combination |
| Cast Iron on Cast Iron | 1.1 | 0.15 | High static, low kinetic friction |
| Cast Iron on Cast Iron (Grease) | — | 0.07 | Machine tool applications |
| Cast Iron on Steel | 0.4 | 0.23 | Common in machinery |
| Copper on Copper | 1.6 | — | Extremely high static friction |
| Copper on Copper (Grease) | 0.08 | — | Lubricated copper surfaces |
| Copper on Steel | 0.53 | 0.36 | Electrical contacts, bearings |
| Copper on Cast Iron | 1.05 | 0.29 | High static friction combination |
| Copper on Glass | 0.68 | 0.53 | Metal on glass interface |
| Brass on Steel (Clean) | 0.51 | 0.44 | Bearing applications |
| Brass on Steel (Lubricated) | 0.11-0.19 | — | With grease or castor oil |
| Glass on Glass (Clean) | 0.9-1.0 | 0.4 | Clean, dry surfaces |
| Glass on Glass (Grease) | 0.1-0.6 | 0.09-0.12 | Lubricated glass surfaces |
| Glass on Metal | 0.5-0.7 | — | Clean surfaces |
| Glass on Metal (Grease) | 0.2-0.3 | — | Lubricated interfaces |
| Iron on Iron | 1.0 | — | Pure iron surfaces |
| Iron on Iron (Grease) | 0.15-0.20 | — | Lubricated iron surfaces |
| Nickel on Nickel | 0.7-1.1 | 0.53 | Clean nickel surfaces |
| Nickel on Nickel (Grease) | 0.28 | 0.12 | Lubricated nickel surfaces |
| Silver on Silver | 1.4 | — | Clean precious metal surfaces |
| Silver on Silver (Grease) | 0.55 | — | Lubricated silver contacts |
| Platinum on Platinum | 1.2 | — | Precious metal contacts |
| Platinum on Platinum (Grease) | 0.25 | — | Lubricated platinum surfaces |
| Wood on Wood (Clean) | 0.25-0.5 | — | Varies with grain direction |
| Wood on Wood (Wet) | 0.2 | — | Moisture reduces friction |
| Oak on Oak (Parallel grain) | 0.62 | 0.48 | Wood grain parallel |
| Oak on Oak (Cross grain) | 0.54 | 0.32 | Wood grain perpendicular |
| Wood on Clean Metal | 0.2-0.6 | — | Construction applications |
| Wood on Wet Metal | 0.2 | — | Moisture present |
| Wood on Concrete | 0.62 | — | Construction interface |
| Wood on Brick | 0.6 | — | Building materials |
| Leather on Oak | 0.61 | 0.52 | Belt drive applications |
| Leather on Metal | 0.4-0.6 | — | Belt drives, brake applications |
| Leather on Cast Iron | 0.6 | 0.56 | Industrial belt systems |
| Ice on Ice (0°C) | 0.1 | 0.02 | Forms water film |
| Ice on Ice (-12°C) | 0.3 | 0.035 | Temperature dependent |
| Ice on Ice (-80°C) | 0.5 | 0.09 | Very cold conditions |
| Ice on Wood | 0.05 | — | Very low friction |
| Ice on Steel | 0.03 | — | Extremely low friction |
| PTFE on PTFE | 0.04 | 0.04 | Teflon on Teflon |
| PTFE on Steel | 0.05-0.2 | — | Non-stick coating applications |
| Waxed Wood on Snow (Wet 0°C) | 0.14 | 0.1 | Skiing conditions |
| Waxed Wood on Snow (Dry) | — | 0.04 | Optimal skiing conditions |
| Ski Wax on Snow (Wet 0°C) | 0.1 | — | Wet snow conditions |
| Ski Wax on Snow (Dry 0°C) | 0.04 | — | Dry powder snow |
| Ski Wax on Snow (Dry -10°C) | 0.2 | — | Cold, dry snow |
| Nylon on Nylon | 0.15-0.25 | — | Plastic on plastic |
| Nylon on Steel | 0.4 | — | Plastic bearing applications |
| Polyethylene on Polyethylene | 0.2 | — | Low friction plastic |
| Polyethylene on Steel | 0.2 | — | Consistent with/without grease |
| Polystyrene on Polystyrene | 0.5 | — | Consistent with/without grease |
| Polystyrene on Steel | 0.3-0.35 | — | Plastic on metal interface |
| Plexiglas on Plexiglas | 0.8 | — | Acrylic plastic surfaces |
| Plexiglas on Steel | 0.4-0.5 | — | Consistent with/without grease |
| Graphite on Steel | 0.1 | — | Solid lubricant |
| Graphite on Graphite | 0.1 | — | Self-lubricating material |
| Graphite on Graphite (Vacuum) | 0.5-0.8 | — | Higher friction without air/moisture |
| Tungsten Carbide on Steel | 0.4-0.6 | — | Hard material applications |
Note: Values are approximate and can vary significantly based on surface conditions, temperature, humidity, load, and material quality. Always consult specific material data for critical applications.
Coefficient of Friction Equation/Formula
The coefficient of friction (μ) is a dimensionless value that describes the resistance to sliding between two surfaces. It is calculated using a simple formula:
μ = Fₓ / Fₙ
Where:
- μ = coefficient of friction
- Fₓ = frictional force (in newtons or pounds)
- Fₙ = normal force (the force perpendicular to the surfaces in contact)
The frictional force is the force resisting motion between surfaces, while the normal force is typically the object’s weight or any force pressing the surfaces together. By dividing the frictional force by the normal force, this equation gives you a value that helps predict how difficult it will be to slide one material across another.
There are two types of friction coefficients commonly used:
- Static coefficient of friction (μₛ): Used when the object is at rest and just about to start moving.
- Kinetic coefficient of friction (μₖ): Used once the object is already in motion.
Example:
If it takes 10 N of force to start moving an object that weighs 20 N, then:
μ = 10 / 20 = 0.5
Parting Thoughts
If you have questions about selecting the right materials or tackling a specific design challenge, our team of product experts and engineers is here to help. MISUMI USA offers a wide range of industrial and automation components—including aluminum extrusions, linear shafts, and metal materials—to support your manufacturing needs. Be sure to explore our extensive catalog, and don’t forget to visit the MechLab Blog for more helpful resources. You’ll find data-driven tools like our Linear Thermal Expansion Coefficient Chart, Metal Melting Points Chart, and other technical calculators to support your next project.
Author: Scott Bredemann | Updated: 8/15/2025
Disclaimer:
The content on this webpage is for informational purposes only. MISUMI makes no guarantees, expressed or implied, regarding the accuracy, completeness, or validity of the information. Performance parameters, tolerances, designs, materials, or processes should not be assumed to reflect third-party suppliers’ or manufacturers’ deliverables within MISUMI’s network. Buyers are responsible for specifying their part requirements