How to Calculate Fire Rate

Rate of Fire (RoF) Calculator

Calculate rounds per minute (RPM) and cycle time

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How to Calculate Fire Rate

Calculating the Rate of Fire (RoF) is essential for ballistics engineering, competitive shooting, and verifying mechanical efficiency of firearms. The standard measurement for fire rate is Rounds Per Minute (RPM).

The Fire Rate Formula

To determine the RPM manually, you use the following mathematical formula:

RPM = (Total Rounds Fired ÷ Time in Seconds) × 60

Practical Example

If you fire a standard 30-round magazine and the elapsed time from the first shot to the last shot is 2.5 seconds, the calculation would look like this:

  • Step 1: 30 rounds ÷ 2.5 seconds = 12 rounds per second (RPS).
  • Step 2: 12 RPS × 60 seconds = 720 RPM.

Key Terms Explained

  • RPM (Rounds Per Minute): The theoretical number of shots fired if the weapon operated continuously for 60 seconds.
  • RPS (Rounds Per Second): The frequency of shots within a single second.
  • Cycle Time: The amount of time (usually in milliseconds) between each individual shot. This is calculated as 1000ms divided by the RPS.
function calculateFireRate() { var shots = document.getElementById("shotsFired").value; var time = document.getElementById("timeElapsed").value; var resultDiv = document.getElementById("rofResult"); // Validation if (shots === "" || time === "" || parseFloat(time) <= 0 || parseFloat(shots) <= 0) { alert("Please enter valid positive numbers for both shots and time."); return; } var shotsVal = parseFloat(shots); var timeVal = parseFloat(time); // Calculations var rps = shotsVal / timeVal; var rpm = rps * 60; var cycleTime = (1 / rps) * 1000; // Output Formatting document.getElementById("rpmOutput").innerHTML = "" + rpm.toLocaleString(undefined, {maximumFractionDigits: 2}) + " RPM (Rounds Per Minute)"; document.getElementById("rpsOutput").innerHTML = "Frequency: " + rps.toFixed(2) + " Rounds Per Second"; document.getElementById("cycleOutput").innerHTML = "Cycle Time: " + cycleTime.toFixed(2) + " ms between shots"; // Show result resultDiv.style.display = "block"; }

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