How to make a sprint script is one of those fundamental skills that every aspiring game developer needs to tuck into their belt early on. Whether you are working in Roblox Studio, Unity, or even a custom engine, the core logic remains pretty much the same: you're essentially telling the game to listen for a specific key press and, while that key is held down, boost the character's movement speed. It sounds simple enough on paper, but if you want it to feel "right"—meaning it doesn't feel clunky or robotic—there are a few extra layers of polish you'll want to add.
When you're first starting out, you might think a sprint script is just a toggle. Press "Shift," go fast. But think about the games you actually enjoy playing. There's usually a bit of a wind-up, maybe a slight change in the camera's field of view, or a stamina bar that keeps you from running across the entire map without a break. In this guide, we're going to break down the logic of how to build this from the ground up, focusing on making it feel smooth and professional.
The Basic Logic: Speed and Input
Before we dive into the actual code, let's talk about what's actually happening behind the scenes. Every character in a game has a "WalkSpeed" or a "MoveSpeed" variable. For most games, this is a set number—let's say 16. When you want to make a sprint script, your goal is to change that 16 to something like 25 or 30 the moment the player hits the Left Shift key.
The most important part of this process is the input detection. You need the game to constantly "listen" for when a player interacts with their keyboard. In most modern game engines, you have two primary events to watch for: "InputBegan" and "InputEnded." If you only use "InputBegan," your character will start sprinting and never stop, which is probably not what you're going for unless you're making an infinite runner. You need that "InputEnded" trigger to return the speed back to normal the second the player lifts their finger off the key.
Setting Up Your Variables
To keep your code clean, you don't want to just type random numbers directly into your functions. That's a recipe for a headache later when you decide the sprint is too fast and have to hunt through fifty lines of code to find the number. Instead, you should define your variables at the very top.
You'll want a NormalSpeed variable, a SprintSpeed variable, and a reference to the Character or Player. By setting these up early, you can tweak the "feel" of your game in one central location. It's also a good idea to create a boolean (a true/false value) called isSprinting. This helps the game keep track of the player's state, which becomes incredibly useful once you start adding animations or stamina systems.
Writing a Simple Sprint Script (The Roblox Example)
Since so many people start their journey in Roblox, let's look at how this logic translates to Luau. You'll typically place this in a LocalScript inside the "StarterCharacterScripts" folder.
First, you grab the UserInputService. This is the service that handles all those keyboard presses we talked about. You'll set a variable for the humanoid, which is the part of the character that actually controls movement. Then, you connect a function to InputBegan. You check if the key pressed is Enum.KeyCode.LeftShift. If it is, you set Humanoid.WalkSpeed to your SprintSpeed.
Then, you do the exact same thing for InputEnded. When the shift key is released, you set the speed back to NormalSpeed. It's straightforward, it's effective, and it gets the job done. But, if you stop there, the transition might feel a bit jarring. The character just "snaps" to a higher speed instantly.
Adding "Juice" with Field of View (FOV)
If you really want to know how to make a sprint script that feels high-quality, you have to talk about visual feedback. When a character starts moving faster, the player needs to see that speed, not just feel it. One of the oldest tricks in the book is slightly increasing the Field of View (FOV) when sprinting.
When you zoom the camera out just a tiny bit—maybe from an FOV of 70 to 80—it creates an illusion of velocity. It makes the environment seem like it's rushing past the player faster. To do this, you'd use a "Tween" or a "Lerp" (Linear Interpolation). Instead of the FOV snapping to a new number, it should slide there smoothly over about 0.2 seconds. This small addition makes your script feel like it belongs in a triple-A game rather than a hobby project.
Incorporating a Stamina System
Let's be real: unlimited sprinting can break some games. If you're making a horror game or a survival sim, you want the player to feel vulnerable. This is where a stamina system comes into play.
To add this to your script, you need a few more variables: MaxStamina, CurrentStamina, and RegenRate. Inside your sprinting function, you need a loop that runs as long as the player is holding Shift. Every "tick" or "frame," you subtract a small amount from the CurrentStamina.
The key here is adding a check: if CurrentStamina > 0 then. If the player runs out of juice, you force the WalkSpeed back to normal, even if they are still holding the Shift key. Then, you need a separate logic block that slowly adds stamina back when they aren't sprinting. It adds a layer of strategy to the movement that players really appreciate.
Common Pitfalls to Avoid
When learning how to make a sprint script, it's easy to run into a few common bugs. One of the biggest is "Speed Stacking." This happens when a script doesn't properly check if the player is already sprinting. If they mash the Shift key, sometimes the script can get confused and keep adding speed until the character is flying across the map like a superhero. Always make sure your script checks the current state before applying a speed boost.
Another issue is Server-Side vs. Client-Side. In multiplayer games, if you only change the speed on the client (the player's computer), the server might think they are cheating because they are moving faster than allowed. This is called "rubber-banding." While the input detection must happen on the client for responsiveness, you often need to communicate with the server to let it know, "Hey, this player is supposed to be moving fast right now."
Making it Work for Mobile and Controllers
Don't forget about your players who aren't using a keyboard! If you're building a game today, there's a good chance someone will play it on a phone or with a PlayStation controller.
For controllers, you'll want to map the sprint to the Left Stick click (L3). For mobile, you'll probably need to create a GUI button on the screen. The beauty of a well-written script is that the "speed changing logic" is separate from the "input logic." You can have one function called StartSprinting() and another called StopSprinting(). Then, you just call those functions whether the player hits Shift, clicks a button on their screen, or presses a button on their controller.
Final Touches: Animations and Sounds
The very last step in mastering how to make a sprint script is adding the sensory details. A character running at 30 speed with a "walking" animation looks ridiculous—like they're sliding on ice. You'll want to trigger a specific "Run" animation when the isSprinting variable becomes true.
The same goes for sound. Footsteps should be faster and perhaps a bit louder when sprinting. You could even add a slight "wind" sound effect that fades in. These tiny details are what keep players immersed.
At the end of the day, a sprint script isn't just about changing a number in the code. It's about enhancing the player's connection to the character. By combining input detection, smooth transitions, stamina limits, and visual feedback, you turn a basic movement mechanic into a polished feature that makes your game world feel more dynamic and responsive. Once you've nailed this, you'll find that many other game mechanics follow a very similar pattern!