Surface Footage Calculator

Calculate surface area, linear footage, and SFM (Surface Feet per Minute) for machining, woodworking, and construction projects.

Calculator Mode

Unit System

Diameter (inches/mm)

RPM (Revolutions per Minute)

Material Type (for reference)

Calculate

Length

Width

Number of Pieces

Include Both Sides

Calculate surface area for panels, boards, sheets, or plates

Length

Length Unit

Number of Pieces

Output Unit

Convert length measurements to linear footage

Outer Diameter

Length

Number of Tubes

Include Ends

Calculate surface area of pipes, tubes, and cylindrical objects

Radius

Height

Number of Cylinders

Include Top & Bottom

Calculate surface area of cylinders (like columns, tanks, rollers)

Result

Calculation Summary

Reference Information

Step-by-Step Solution

Select a mode and enter values, then click "Calculate" to see the step-by-step solution.

SFM Reference Chart

Aluminum	300-600 SFM
Mild Steel	80-120 SFM
Stainless Steel	40-80 SFM
Brass	200-500 SFM
Hardwood	500-1000 SFM
Plastic	200-400 SFM

Formulas Used

SFM: (π × Diameter × RPM) ÷ 12
RPM: (SFM × 12) ÷ (π × Diameter)
Rectangle Area: Length × Width × Sides
Tube Area: π × OD × Length
Cylinder Area: 2πr × h + (ends if included)

Common Conversions

1 foot = 12 inches
1 yard = 3 feet
1 meter = 3.28084 feet
1 inch = 25.4 mm
1 board foot = 144 cubic inches

Frequently Asked Questions

What is SFM (Surface Feet per Minute)?

SFM (Surface Feet per Minute) is a measure of how fast the cutting surface of a tool moves across the workpiece. It's critical for determining proper cutting speeds in machining operations like milling, turning, and drilling.

How is SFM calculated?

SFM = (π × Diameter × RPM) ÷ 12

Where diameter is in inches and RPM is revolutions per minute. For metric, use mm and divide by 1000 for meters.

What is the recommended SFM for different materials?

Aluminum: 300-600 SFM
Mild Steel: 80-120 SFM
Stainless Steel: 40-80 SFM
Brass: 200-500 SFM
Hardwood: 500-1000 SFM

How do you calculate surface area of a tube?

The surface area of a tube (cylindrical surface) is: Area = π × Outer Diameter × Length. For total surface area including ends, add 2 × (π × r²).

How many board feet are in a 2x4x8?

A 2x4x8 board contains 5.33 board feet. Calculation: (2 × 4 × 8) ÷ 12 = 5.33 bd ft.

What is the difference between SFM and RPM?

RPM measures spindle rotation speed, while SFM measures the actual cutting speed at the tool's outer edge. For larger diameter tools, the same RPM produces higher SFM.