Shotgun Choke Calculator

Pattern spread at distance from choke and load.

Choke type (0-6)

Distance (yards)

Shot size (#)

Payload (oz)

Tab to move between fields

Pattern diameter (in)

28.8

Pellets in 30" circle323

Total pellets in load461

Density (pellets/sq in)0.5

Effective range (yds)56

Pattern percentage (%)70%

How to Use This Calculator

Select Choke Type (0=Cylinder through 6=Extra Full) using the number input.
Enter Distance to the target in yards and Shot Size (e.g., #8 for skeet, #6 for field).
Set Payload in ounces (standard field load is 1 to 1.25 oz).
Review Pattern Diameter, Pellets in 30-inch Circle, Pattern Density, and Effective Range.
Use Pattern Percentage to select the optimal choke for your target distance.

How the result changes with Distance (yards)

Choke type (0-6): 0=Cylinder, 1=Skeet, 2=IC, 3=Modified, 4=IM, 5=Full, 6=Extra Full.
Distance (yards): Distance from muzzle to target in yards.
Shot size (#): Shot size number (e.g. #8 for skeet, #6 for field).
Payload (oz): Total shot weight in ounces.

Pattern diameter (in): Approximate diameter of the shot pattern at the given distance.
Pellets in 30" circle: Estimated pellets landing within a 30-inch circle.
Total pellets in load: Approximate number of pellets in the shot charge.
Density (pellets/sq in): Pellet density within the effective pattern.
Effective range (yds): Estimated maximum effective range for this choke/load combination.
Pattern percentage (%): Percentage of pellets landing in the 30-inch circle at this distance.

Identify Input Parameters
4 parameters
Choke type (0-6) = 5, Distance (yards) = 40, Shot size (#) = 8, Payload (oz) = 1.125 = 4 input(s) provided
Calculate Pattern diameter
Pattern diameter = spreadRateInPerYd * distanceYds
28.8 = 28.8
Calculate Pellets in 30
Pellets in 30 = round(totalPellets * (adjustedPct / 100))
323 = 323
Calculate Total pellets in load
461 = 461