Output Shaft Speed Calculator

Analyze RPM reduction, torque multiplication, and linear velocity for gears, chains, and belts.

Please enter RPM and Component Sizes.

Output Shaft Speed 0 RPM

Input

Output

Input RPM

Output RPM

Speed Ratio: 0.00:1

Output Torque: —

Efficiency Loss: 0%

Effective Slip: 0 RPM

Surface Speed: 0 fpm

Configuration: —

Engineering Note: —

What is an Output Shaft Speed Calculator?

An Output Shaft Speed Calculator is a tool that tells you how fast a driven shaft will rotate after power passes through gears, sprockets, chains, or belts.

You start with a known input speed, usually from a motor or engine. The calculator then applies the mechanical ratio, efficiency, and slip to show what happens at the output shaft.

In simple terms, it answers questions like:

If my motor runs at 1750 RPM, how fast will the output shaft turn?
How much torque do I gain or lose?
Does belt slip change the final speed?
Am I reducing speed or increasing it?

This calculator is built for real-world use. It goes beyond basic math by including efficiency losses, belt slip, torque change, and even surface speed.

Why Output Shaft Speed Matters

Shaft speed directly affects how a machine behaves. If the speed is wrong, the system can fail, wear out faster, or never work as intended.

Here are common situations where output shaft speed matters:

Conveyors that need steady, slow movement
Fans and pumps that require higher speed
Lifting systems where torque matters more than RPM
Belt-driven machines where slip reduces real output

Using a calculator helps you design smarter instead of guessing.

What This Calculator Can Do

This Output Shaft Speed Calculator is designed to be practical, not theoretical. It provides several useful results at once.

Core outputs

Output shaft speed (RPM)
Speed ratio (reduction or overdrive)
Output torque (if input torque is provided)

Advanced insights

Efficiency loss
Belt slip impact
Linear surface speed (for belt systems)
Configuration type (reduction, overdrive, or 1:1)

It also includes visual bars and engineering notes to make results easier to understand at a glance.

Drive Systems Supported

The calculator supports two common mechanical systems.

Gears and sprockets

Uses number of teeth
Assumes no slip
Very high efficiency
Common in gearboxes and chain drives

Belts and pulleys

Uses diameter
Allows slip percentage
Slightly lower efficiency
Common in fans, compressors, and machinery

You choose the system type first, and the calculator adjusts the inputs automatically.

How the Calculation Works (Plain English)

You do not need to know formulas to use the tool, but understanding the logic helps.

Step 1: Speed ratio

The ratio compares the driven component to the driver.

Larger driven part → speed goes down, torque goes up
Smaller driven part → speed goes up, torque goes down

Step 2: Theoretical output speed

The input RPM is multiplied by the inverse of the ratio.

This gives an ideal speed with no losses.

Step 3: Slip adjustment

For belts, slip reduces real speed.
For gears and chains, slip is zero.

The calculator subtracts this loss automatically.

Step 4: Torque calculation

If you enter input torque, the calculator increases or decreases torque based on the ratio and efficiency.

Lower speed almost always means higher torque.

Step 5: Linear velocity

For belt systems, the tool estimates surface speed in feet per minute.
This helps check if belt speed is within safe limits.

Understanding the Results