Minute of Angle (MOA) Calculator
Calculate Minute of Angle (MOA) for shooting and optics. Enter distance, spread, or MOA to find the missing value using the exact angular measurement formula for riflescopes and ballistics analysis.
About This Calculator
The Minute of Angle (MOA) Calculator helps shooters, hunters, and precision marksmen compute the angular spread of their shots at any distance. MOA is the standard unit for measuring firearm accuracy and adjusting rifle scopes. Simply enter any two values — distance in yards, spread in inches, or MOA — and the calculator instantly determines the third using both the exact trigonometric formula and the shooter's approximation.
The exact formula used is: MOA = (Spread × 10800) / (π × Distance), where spread and distance are in the same units. This is derived from the fact that 1 MOA equals 1/60th of a degree, and the spread forms an arc on a circle with radius equal to the shooting distance. The calculator also provides the shooter's standard approximation (1 MOA ≈ 1 inch per 100 yards) alongside the exact value, plus a MIL (milliradian) conversion for shooters who use MIL-based scopes.
Two interactive charts help visualize the relationship: the MOA vs Distance chart shows how the MOA value changes with distance for a given spread, while the Spread vs Distance chart shows how the linear spread grows as distance increases for a given MOA. Understanding these relationships is essential for long-range shooting, scope adjustment, and ballistic compensation.
Regional Notes
United States: MOA is the most common unit for rifle scope adjustments and accuracy measurement. Most American-made scopes use 1/4 MOA or 1/2 MOA click adjustments. The standard shooting distance for MOA calibration is 100 yards.
United Kingdom: MOA is also widely used in UK shooting sports, particularly for fullbore rifle shooting at ranges like Bisley. Distances are typically measured in yards or meters, and MOA adjustments are standard on many target scopes.
International (Metric): In many countries, MIL (milliradian) scopes are more common than MOA. The calculator provides MIL conversion for easy cross-referencing. To convert MOA to MIL, divide by 3.438. Shooters can also use meters instead of yards by entering the equivalent spread in centimeters.
Frequently Asked Questions
What is MOA in shooting?
MOA stands for Minute of Angle, an angular measurement commonly used in shooting and optics. One MOA equals 1/60th of a degree. At 100 yards, 1 MOA corresponds to approximately 1 inch of spread, making it a standard unit for measuring rifle accuracy and adjusting scopes.
How do you calculate MOA?
MOA is calculated using the formula: MOA = (Spread × 10800) / (π × Distance), where spread and distance are in the same units. For a quick estimate, shooters use the approximation: 1 MOA ≈ 1 inch per 100 yards. Simply divide the spread in inches by the distance in yards and multiply by 100.
What is 1 MOA at 100 yards?
1 MOA at 100 yards equals approximately 1.047 inches using the exact formula, though shooters commonly round it to 1 inch for quick calculations. This means if your rifle shoots 1 MOA, all shots will land within a 1-inch circle at 100 yards.
How do I convert MIL to MOA?
To convert MIL (milliradians) to MOA, multiply the MIL value by approximately 3.438. Conversely, to convert MOA to MIL, divide the MOA value by 3.438. Some scopes use MIL adjustments while others use MOA, so this conversion is essential when switching between optic systems.
What is the difference between MOA and MIL?
MOA (Minute of Angle) and MIL (milliradian) are both angular measurements used in rifle scopes. MOA uses degrees (1/60th of a degree), while MIL is based on radians (1/6400th of a circle). MOA is more common in US shooting sports, while MIL is widely used in military and long-range precision shooting worldwide.
How can I measure my rifle's MOA accuracy?
To measure your rifle's MOA, shoot a group of 3-5 shots at a known distance (typically 100 yards). Measure the center-to-center spread of the widest two shots in inches, then divide by the distance in hundreds of yards. For example, a 1.5-inch group at 100 yards equals 1.5 MOA.
Why does MOA increase with distance?
MOA itself is a fixed angle, so 1 MOA is always the same angle regardless of distance. However, the linear spread that 1 MOA represents increases with distance. At 100 yards it equals about 1 inch, at 200 yards about 2 inches, and at 500 yards about 5 inches. This is why longer shots require finer accuracy.
What MOA should a good rifle shoot?
A good hunting rifle typically shoots 1-2 MOA, meaning a 1-2 inch group at 100 yards. Precision rifles can achieve sub-MOA accuracy (under 1 inch at 100 yards). Military snipers often require 0.5 MOA or better. Factory hunting rifles averaging 1.5 MOA are considered acceptable for most hunting applications.