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How Arma Reforger Mortar Calculations Work: Range, Elevation, and Map Grid

Learn how to calculate mortar firing solutions in Arma Reforger — range from grid coordinates, elevation angle, and azimuth from observer to target using military map grid math.

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How Arma Reforger Mortar Calculations Work

Arma Reforger uses realistic military mortar procedures. To fire a mortar accurately, you need three values: 1. Range — distance from mortar to target (meters) 2. Azimuth — direction from mortar to target (mils or degrees) 3. Elevation — barrel angle setting (mils) for the correct range

Step 1: Calculate Range from Grid Coordinates

If you have mortar position and target position on the map:

Arma Reforger uses military grid coordinates (northing and easting in meters).

Range (m) = √((ΔEasting)² + (ΔNorthing)²)

Example: - Mortar position: Easting 5420, Northing 3180 - Target position: Easting 5680, Northing 3450

ΔEasting = 5680 − 5420 = 260 m ΔNorthing = 3450 − 3180 = 270 m

Range = √(260² + 270²) = √(67,600 + 72,900) = √140,500 = 374.8 m ≈ 375 m

Step 2: Calculate Azimuth (Direction)

Azimuth = arctan(ΔEasting / ΔNorthing)

From the example: Azimuth = arctan(260 / 270) = arctan(0.963) = 43.9° ≈ 44°

Adjust for quadrant: - ΔE positive, ΔN positive: azimuth = calculated value (NE quadrant) → 44° - ΔE positive, ΔN negative: azimuth = 180° − value (SE) - ΔE negative, ΔN negative: azimuth = 180° + value (SW) - ΔE negative, ΔN positive: azimuth = 360° − value (NW)

Convert degrees to mils: Mils = Degrees × 17.778 (NATO standard: 6,400 mils per circle) 44° × 17.778 = 782 mils

Step 3: Elevation from Range

Mortar elevation is read from a firing table specific to the ammunition and charge. In Arma Reforger, the M252 81mm mortar firing table (simplified):

Range (m)Elevation (mils) — Charge 1Elevation (mils) — Charge 4
1001,500
2001,425
3001,350
4001,2751,450
5001,400
6001,350
8001,275
1,0001,200
1,5001,075

*Values are representative — use in-game firing tables for accuracy*

At 375 m (interpolating between 300 and 400 m, Charge 1): Elevation ≈ 1,350 + 0.75 × (1,275 − 1,350) = 1,350 − 56 = ~1,294 mils

Adjusting for Height Difference

If target and mortar are at different altitudes, add or subtract:

Elevation adjustment ≈ arctan(ΔHeight / Range) × 1,018.6 mils/radian

For ΔHeight = +30 m uphill at 375 m range: Angle = arctan(30/375) = arctan(0.08) = 4.57° = 81 mils Add 81 mils to elevation setting.

Call for Fire Format

When radioing fire support: 1. Observer ID: "Alpha-1 to Fire Support" 2. Warning Order: "Adjust fire, over" (adjust) or "Fire for effect, over" (immediate) 3. Target Description: "Infantry in the open, 5 man" 4. Target Location: Grid coordinates or polar (direction + range from landmark) 5. Method of Engagement: Mortar, 3 rounds HE 6. Method of Control: At my command / Rounds complete

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Frequently Asked Questions

How do I calculate mortar range from grid coordinates in Arma Reforger?
Range = √((ΔEasting)² + (ΔNorthing)²). Subtract mortar easting from target easting for ΔE; mortar northing from target northing for ΔN. Example: mortar at (5400, 3200), target at (5700, 3500): ΔE=300, ΔN=300, Range = √(90,000+90,000) = √180,000 = 424 meters.
How do I calculate azimuth from mortar to target?
Azimuth (degrees) = arctan(ΔEasting / ΔNorthing), adjusted for quadrant. If target is northeast: azimuth = arctan value directly. Southeast: 180° − value. Southwest: 180° + value. Northwest: 360° − value. Convert to mils by multiplying by 17.778 (NATO 6,400 mil standard). Most Arma Reforger mortar calculators accept degree input and convert automatically.
What elevation should I set for my mortar in Arma Reforger?
Elevation comes from the ammunition firing table for your range. In Arma Reforger, open the mortar's in-game firing table interface, select your charge, and read the elevation in mils for your calculated range. Interpolate between table entries for ranges not listed. Higher elevation (closer to 1,600 mils) = shorter range; lower elevation = longer range.
What does mils mean in artillery and mortars?
Mils (milliradians) are angular measurement units used in military artillery. NATO standard uses 6,400 mils per full circle (compared to 360 degrees). 1 mil subtends approximately 1 meter at 1,000 meters distance — useful for quick offset calculations. Convert: degrees × 17.778 = mils; mils ÷ 17.778 = degrees.

Last updated 7/28/2026