V-Belt Size Calculator for Farm Drives

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V-Belt Size Calculator

Size pitch length, belt speed, and wrap angle for farm drives, pumps, augers, fans, and conveyor runs.

Use pitch diameters and shaft center distance for best accuracy. The calculator compares the result with standard belt sizes and section limits.
Imperial uses in and ft/min. Metric uses mm and m/min.
Open drives are typical for V-belts. Crossed drives are included for edge cases.
The section sets the minimum small pulley guidance.
Use the actual shaft speed at the driver pulley.
Measure the pitch diameter, not the outside diameter.
The driven pulley can be larger or smaller than the driver.
This is the distance between shaft centers.
This note is stored with the live result only.
Use pitch diameters for accurate belt length.
Calculated fit

Result Summary

Ready for belt sizing.
Pitch length
-
in / mm
Nearest standard
-
in / mm
Belt speed
-
fpm / m/min
Small pulley wrap
-
deg

🧰 Breakdown

🔧 Section Spec Grid

A
Top width1/2 in
Height5/16 in
Min small pulley3 in
Light drive
B
Top width21/32 in
Height13/32 in
Min small pulley5 in
General use
C
Top width7/8 in
Height17/32 in
Min small pulley7 in
Heavy load
D
Top width1 1/4 in
Height3/4 in
Min small pulley9 in
Large drive
3V
Top width3/8 in
Height7/32 in
Min small pulley2.6 in
Compact set
5V
Top width21/32 in
Height13/32 in
Min small pulley4.4 in
High power
SPZ
Top width10 mm
Height8 mm
Min small pulley50 mm
Metric light
SPA
Top width13 mm
Height10 mm
Min small pulley80 mm
Metric mid
SPB
Top width17 mm
Height14 mm
Min small pulley125 mm
Metric heavy
SPC
Top width22 mm
Height18 mm
Min small pulley200 mm
Metric max

📊 Reference Tables

📊 Standard Pitch Length Bands

BandFitDriveNote
20-40 inShortFansTight
42-72 inMidPumpsCommon
74-120 inLongAugersFarm
124-200 inExtraChippersBig

📊 Ratio and Wrap Guide

RatioWrapLayoutHint
1:1BestEasyLeast slip
1.5:1GoodCommonBalanced
2:1CheckLong spanUse idler
3:1TightShort spanWatch arc

📊 Section Quick Compare

SectionTypeMin pulleyUse
ALight3 inFans
BGeneral5 inPumps
CHeavy7 inAugers
SPZMetric50 mmCompact

💡 Tips

Tip: Measure pitch diameters, not outside diameters, or the belt will read long.
Tip: Pick the nearest standard length, then confirm tensioner travel and wrap angle.
The live result uses belt pitch geometry, compares standard lengths, and flags small pulley limits for the selected section.

Choose the right vbelt size well especially for lawn and garden machines and other farm tools. Various kinds of vbelts are available, for instance light duty for motors with fractional horsepower and classical heavy duty belts in many sizes

Vbelt cross sections you classify according to top width and depth. Every combination of width and depth marks by a letter. So, vbelts with 21/32 inch width and 7/16 inch depth are called “B” belt.

How to Choose the Right V-Belt Size

The standard 1/2 inch A vbelt stays the most reliable on the market. Many fan belts have 1/2 inch measure, but if it reaches 5/8 inches, you classify it as a type B belt. You call type AX vbelt cogged or notched.

Prefixes 2L, 3L, 4L and 5L point to light duty by the “L”. They are for motors under 1 HP. L style belts you commonly call light duty industrial or lawn and garden. A, B, C, D, E and AX, BX, CX, DX size belts are more industrial.

You do not measure belts by diameter nor folding them in half. The best way to estimate circumference of vbelt is by a vbelt measuring tool or flexible cloth tape, not a steel ruler. Otherwise you can wrap a small string around it and estimate the string.

Automotive belts measure in inches, with numbers according to outside circut.

The usual part number format for classical vbelts is the cross section size and inside length in inches. For instance B50 shows a B section of 50 inches. Classical vbelts will last in hard conditions.

Most stores sell them in two widths and lengths in half-inch steps.

To find the right belt, first identify the section, then check if it is wrapped or notched, and finally measure the length. Vbelt size charts describe top width, height and how to find a part number based on outside or inside circumference. Online calculators also help: enter distance between pulley, diameter of big pulley and small, and it gives the needed length.

Check the gear manual first. Searching for part numbers on the old belt also is usefull. Pulley size matters, namely outside diameter and width of the groove.

Spare belts you should hang on something with diameter no less than the smallest sheave for thosebelts.

V-Belt Size Calculator for Farm Drives

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