Rounds Per Minute Calculator

Rounds Per Minute (RPM) is an important performance measurement that helps describe a firearm’s firing rate and operational capacity. We have prepared a Rounds Per Minute (RPM) calculator that shows how many rounds a firearm would discharge in one minute under continuous operation. 

In simple words, RPM is a quick and useful method to measure a firearm’s firing rate during sustained fire.

In this article, I will go in depth, step by step, to explain what RPM is, how it works, why it matters for firearm performance, and how to calculate RPM for different firearms with some practical examples.

What does rounds per minute mean?

Rounds Per Minute (RPM) is a key metric that helps determine the performance of a firearm. In simple words, RPM means how many rounds a weapon can fire in 60 seconds under ideal conditions, depending on weapon is semi-automatic or fully automatic.

For example, if a rifle has a theoretical fire rate of 600 RPM, it means 600 rounds per minute under ideal conditions. In real-world cases, many factors constrain the sustained fire rate, such as reloading, overheating, and mechanical limitations.

Why Does RPM Matter:

RPM is an essential key metric in the weapon world. It helps in many cases such as:

• Equipment Comparison: It helps compare firearm theoretical firing rate capacities.
• Preparedness and training: RPM helps in planning for the demands of sustained firing, including ammunition consumption and heat management.
• Operational Use: Higher RPM can be useful in some cases, but it is not always beneficial—controlled fire and accuracy are often more important.

How to calculate rounds per minute — formula & example

You can use our precise Rounds Per Minute (RPM) calculator to gauge your firearm’s rate of fire, which can help you understand weapon capacity, efficiency, and performance.

Estimating RPM is simpler than you might think. You just need to determine:

• Total number of rounds fired
• How much time was taken (in seconds)

Once you have the data needed, divide the total number of rounds by the time taken in seconds, then multiply the result by 60 to calculate RPM.

Here’s the formula:

• RPM = (Number of Rounds / Time Taken in seconds) × 60

You no longer need to do the math manually; you can plug in values into the inputs to estimate RPM:

• Number of Rounds: How many total rounds were fired from the firearm.
• Time Taken: How much time it takes to fire them.
• Rounds per Minute (RPM):  Within half a second, this calculator computes and shows your firing rate in rounds per minute.

Likewise, you can fill in any two input values, and the remaining empty field will be automatically calculated based on those inputs—this is the power of the bidirectional feature.

Example 1: fully automatic rifle:

Let's assume you fire 90 rounds in the duration of 30 seconds. Now compute its RPM:

• Number of rounds: 90
• Time taken: 30 seconds

Plug in the formula:

• RPM = (90 / 30) × 60
• RPM = 3 × 60 = 180

This means the rifle’s performance is 180 RPM under continuous fire conditions.

Example 2: semi-automatic pistol:

For example, you fire 10 rounds with a pistol in 10 seconds:

• Number of rounds: 10
• Time taken: 10 seconds

Using the formula:

• RPM = (10 / 10) × 60
• RPM = 1 × 60 = 60

This example shows the pistol’s capacity is 60 RPM.

So far, we have demonstrated how to calculate the RPM of a rifle and a pistol. The RPM provides a practical benchmark for the firearm.

Convert RPM to rounds per second (RPS) and seconds-per-shot

If you want to convert RPM to rounds per second (RPS) and seconds per shot, here’s how to get both values from an RPM.

We use these equations:

• RPS = RPM / 60
• Seconds per Shot = 1 / RPS

An example is the simplest way to clearly explain the logic. We will explain it with examples to make things easier to understand about RPS and seconds per shot:

Example: convert 600 RPM to RPS and seconds per shot

In the following steps, we clearly explain how you can convert the 600 RPM to RPS and second per shot:

1. First, convert the RPM to RPS by dividing the 600 by 60:
   • RPS = 600 / 60 = 10.
2. This means 600 RPM equals 10 rounds per second (RPS).

Now it's time to evaluate the seconds per shot.

1. To calculate seconds per shot, divide 1 by 10:
   • Seconds per Shot = 1 / 10 = 0.1 seconds
2. So, we have calculated that at 600 RPM, one bullet is fired in every 0.1 seconds.

Sustained (practical) vs cyclic (theoretical) RPM — what affects sustained fire

Keep in mind, most weapons can't sustain their listed RPM if they continuously fire without interruption. Only some weapons can sustain their cyclic RPM because they are built to account for factors such as feeding, heat buildup, power problems, mechanical stress, and more.

There is a big difference between cyclic RPM and sustained RPM.

Cyclic RPM

It represents the maximum mechanical fire rate that a weapon could achieve under ideal conditions. Remember cyclic rpm assumes:

• No overheating
• No reloading time
• Continuous operation without interruption

Sustained RPM

This is the RPM when the weapon is used in a real-world scenario. The factors that affect it include:

• Magazine capacity
• Reloading time
• Barrel heat buildup
• Fire control
• Ammunition and feeding

The difference between cyclic RPM and sustained RPM makes sense because when a weapon is used in the real world it goes through many practical constraints.

Comparison table — common weapon RPMs (AK-47, Minigun, Pistol)

We have prepared a popular weapons comparison table showing cyclic and sustained RPM values, based on wikipedia:

Conclusion:

Rounds per minute (RPM) is a simple and highly informative metric for everyone who works with firearms, whether using it for personal, professional, or research purposes. Knowing rounds per minute gives you insights into weapon efficiency, ammunition usage, and heat management.