Here's how to calculate RPM (Rounds Per Minute) for weapon fire rate in Godot 4 (in GDscript)

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The name’s Demetrius Dixon. I’m the creator of the PvP arena shooter, Monkanics.

I wanted to give out this quick tip for any shooter game developer looking for a way to convert their weapon fire rate to RPM (Rounds Per Minute), instead of Seconds Per Round (SPR) within the actual codebase itself.

For context, RPM is the standard unit of measurement for most shooter game fire rates. As it gives a large, readable number instead of a really small decimal (i.e. 0.00032 SPR). Seconds Per Round is also really cumbersome to work with in my opinion.

But the solution and formula are actually really simple to implement.

To calculate RPM (Rounds Per Minute), use the following formula:

60 / Your_Desired_RPM

For example, if I wanted a fire rate of 500 RPM, you can save a fire rate variable like this:

var Fire_Rate = 60 / 500

await get_tree().create_timer(Fire_Rate).timeout

This equals to 0.12 Seconds Per Round, but it’s in a much more readable format for the developer.

If you wanted a crazy fire rate like 10,000 RPM in SPR, you’d have to type 0.006.

That sounds pretty simple, but making changes is very inefficient. As unless you’re a math prodigy, you’ll have to use a calculator EVERY SINGLE TIME you want to make a change to a fire rate value, no matter how big or small.

So if you wanted to update 0.006 fire rate to be faster, you have to subtract 0.001 or 0.0005. Decreasing the fire rate? Add 0.00001 or 0.002. It’s backwards!

You get the picture! the logic is very unintuitive and is a hassle to maintain. RPM is simply easier to develop day-to-day.

But there’s an even better way to calculate RPM!

Simply create your own formula function that returns your fire rate like so:

func calculate_fire_rate_delay(Rounds_Per_Minute) -> float:
	
	# Formula for calculating RPM for easy fire rate implementation
	return 60 / Rounds_Per_Minute

Then, put this into your fire rate delay timer like so (The example I’m using is 500 RPM):

await get_tree().create_timer(calculate_fire_rate_delay(500)).timeout

You can change that float value all you like, then Godot will handle the all the annoying decimal math for you. Work smarter, not harder.

For those of you who prefer Rounds Per Second (RPS), the formula is the following:

1.0 / Your_Desired_RPS

func calculate_fire_rate_delay(Rounds_Per_Second) -> float:
	
	# Formula for calculating RPS for easy fire rate implementation
	return 1.0 / Rounds_Per_Second

await get_tree().create_timer(calculate_fire_rate_delay(10)).timeout

This was for 10 rounds per second. Which equates to 60 RPM.

I still find RPS annoying to work with, so I stick with RPM.

I hope this small guide helps a least 1 fellow Google searcher and game developer with implementing fire rates easier.

– Demetrius Dixon

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