Sprocket and Chain Calculator

Calculation setup

Calculation mode

Unit system

Decimal precision

Automatically recalculate after input changes

Sprocket and speed inputs

Driver sprocket teeth

Driven sprocket teeth

Minimum preferred teeth

Driver speed

RPM

Desired output speed

RPM

Used by the driven-teeth mode.

Center distance

Known chain links

Used by the center-distance mode.

Chain standard and dimensions

Chain family

Chain size preset

Presets fill common nominal dimensions.

Chain strands

Chain pitch

Roller diameter

Roller or inside width

Chain mass per length, per strand

kg/m

Working-load rating, per strand

Breaking strength, per strand

Power, load, and duty inputs

Motor power

Input torque

N·m

Used when power is left blank.

Drive efficiency

Driven-machine duty

Starting condition

Shock level

Operating hours per day

Custom service factor

Overrides the calculated service factor.

Maximum allowable shaft load

Installation and maintenance options

Lubrication method

Drive orientation

Operation type

Reversing drive

Idler sprocket

Wear allowance

Maximum chain elongation

Center adjustment allowance

Formula used

Speed ratio
Ratio = driven teeth ÷ driver teeth

Driven speed
N₂ = N₁ × driver teeth ÷ driven teeth

Pitch diameter
D = pitch ÷ sin(180° ÷ teeth)

Chain speed
v = pitch × driver teeth × RPM ÷ 60

Chain length in pitches
L = 2C + (T₁ + T₂) ÷ 2 + (T₂ − T₁)² ÷ (4π²C)
Center distance C is measured in chain pitches.

Torque
Torque = power ÷ angular speed

Effective chain pull
Pull = design power ÷ chain speed

How to use this calculator

Select the required calculation mode and unit system.
Enter both sprocket tooth counts and driver speed.
Choose a chain preset or enter custom dimensions.
Provide center distance or a known link count.
Enter power, duty, rating, and maintenance information.
Review results, warnings, and required manufacturer checks.
Export the result as CSV, PDF, or printed output.

Example calculation data

Input	Example value	Purpose
Driver sprocket	18 teeth	Defines the driving pitch circle.
Driven sprocket	54 teeth	Creates a 3:1 speed reduction.
Driver speed	1,450 RPM	Calculates output speed and chain velocity.
Chain pitch	12.7 mm	Matches a common half-inch chain pitch.
Center distance	600 mm	Determines the required number of links.
Motor power	5.5 kW	Supports torque and tension calculations.

Common ANSI chain pitch reference

Chain	Pitch	Nominal roller diameter	Nominal inside width
#25	0.250 in	0.130 in	0.125 in
#35	0.375 in	0.200 in	0.188 in
#40	0.500 in	0.312 in	0.312 in
#50	0.625 in	0.400 in	0.375 in
#60	0.750 in	0.469 in	0.500 in
#80	1.000 in	0.625 in	0.625 in
#100	1.250 in	0.750 in	0.750 in
#120	1.500 in	0.875 in	1.000 in

Dimensions are nominal references. Confirm the exact selected standard.

Design guidance

Tooth count More teeth generally reduce articulation and chordal speed variation.

Center distance Moderate spacing supports wrap, adjustment, and stable chain travel.

Lubrication Higher speed and load usually require more controlled lubrication.

Ratings Use manufacturer working loads rather than breaking strength alone.

Alignment Keep shafts parallel and sprocket faces correctly aligned.

Inspection Check elongation, tooth wear, tension, guards, and lubrication regularly.

Frequently asked questions

How is sprocket ratio calculated?

Divide driven sprocket teeth by driver sprocket teeth.

Does a larger driven sprocket reduce speed?

Yes. It reduces output speed and increases available torque.

Why does the calculator round chain links?

Roller chains normally use whole pitches and even link counts.

What is adjusted center distance?

It is the spacing matching the selected whole link count.

What is a service factor?

It increases design power for duty, shock, starts, and hours.

Can torque replace motor power?

Yes. Enter torque and RPM while leaving power blank.

Why is wrap angle important?

Adequate wrap lets more sprocket teeth share transmitted load.

When should multiple chain strands be used?

Use them when one strand cannot meet required capacity.

Are estimated sprocket diameters final manufacturing dimensions?

No. Final tooth geometry must follow the selected standard.

Can this replace a manufacturer selection guide?

No. Always verify ratings, speed limits, lubrication, and safety.

Important design limitation

This calculator provides preliminary engineering estimates. Chain capacity depends on manufacturer ratings, environment, alignment, lubrication, temperature, corrosion, and dynamic loading. A qualified designer should confirm every safety-critical installation before equipment operation.