Support

A photo of your target (from the camera or your library), at least one known dimension on the target to set the scale (such as a 1" grid square, a printed circle, or the distance between two marks), the shooting distance in yards, and your scope's click value. Everything else — shooter, ammo, conditions — is optional but useful for the saved record.

After your target photo opens, drag across any dimension you know in real life — the width of a 1" grid square is ideal. When you lift your finger, enter the real-world length in inches. MOACalc uses this to convert pixel distances into physical measurements. You can drag either yellow endpoint to fine-tune the line, or tap Redraw Line to start over.

Almost always a scale issue. Make sure the dimension you entered matches the line you drew — for example, if you drew across two 1" squares and entered 1", the scale is off by 2×. Also confirm the shooting distance is correct in the session setup; MOA scales with distance.

Pinch to zoom on the canvas at any time. To pan while zoomed in, tap the scope icon in the top-right corner to switch to Pan Mode (hand icon) — single-finger drag then pans the image freely. Tap the icon again to switch back to Mark Mode to continue placing shots. Double-tap resets zoom to fit.

Yes. In Mark Mode, drag any existing shot circle to reposition it. The aiming point (green crosshair) can also be dragged at any time. Use Undo Shot to remove the most recently placed shot.

Extreme Spread is the maximum center-to-center distance between any two shots in the group — the standard measure of group size in precision shooting. MOACalc finds the two shots farthest apart and measures the distance between their centers, then converts to inches and MOA at your shooting distance.

The centroid is the average position of all your shots — the geometric center of the group. MOACalc measures the distance from the centroid to your aiming point to determine how far off zero you are. The scope correction is calculated from this offset, not from any single shot.

MOACalc converts the horizontal and vertical offset (centroid vs. aiming point) into your scope's adjustment unit (MOA or Mil), then divides by the click value you entered. For example, a 0.5 MOA horizontal offset with a ¼ MOA scope requires 2 clicks right. The result shows both the click count and the equivalent MOA or Mil value.

Both are angular units that describe size or offset at a given distance. 1 MOA ≈ 1.047" at 100 yards; 1 Mil = 3.6" at 100 yards. MOACalc displays results in both units. Choose the one that matches your scope's turrets — set the adjustment unit and click value in session setup.

Extreme Spread requires at least two points to measure. With only one shot, there's no group size to compute. The Calculate button is enabled once you've placed at least 2 shots and set your aiming point.

Yes. Profiles are stored in SwiftData on your device and are preserved across app updates using lightweight migration. Custom calibers you've added are stored separately in UserDefaults and also persist across updates.

Make sure the firearm profile has a caliber saved. Go to the Profiles tab, tap the firearm to edit it, and confirm a caliber is selected. Once a caliber is saved on the profile, selecting that firearm in session setup will fill both the caliber name and diameter automatically.

Yes — tap Save to Photos on the Results screen to export the fully annotated image (with all session data printed on it) to your Camera Roll at full resolution. From there you can share it, email it, or back it up like any other photo.

Tap the Open Settings button that appears below the error message. That takes you directly to MOACalc's entry in iOS Settings where you can enable Location access. Choose While Using the App. Location is only used to fetch weather conditions — it is never stored or transmitted.