If you've been working on a project and realized your world feels a bit static, adding a roblox custom clock script is one of the easiest ways to breathe some life into your environment. Whether you want a digital display on the player's HUD or a physical grandfather clock ticking away in a spooky mansion, getting the timing logic right is key. It's not just about showing the time; it's about creating an atmosphere that makes the game feel like a living, breathing place.
Why Bother With a Custom Clock?
You might be thinking, "Doesn't Roblox already have a lighting system that handles time?" Well, yeah, it does. But the default system is pretty bare-bones. If you want to show the player exactly what time it is—maybe because you have a shop that only opens at night or a specific event that triggers at noon—you need a script that can communicate that data clearly.
A custom clock gives you total control. You can make time move faster than real life (which is usually a good idea, because nobody wants to wait twelve actual hours for nightfall), and you can format it exactly how you want. Plus, it's a great way to practice your Luau scripting skills without getting bogged down in overly complex physics or data stores.
Getting the Foundation Ready
Before we even touch the code, we need a place for the time to show up. You've basically got two choices here: a ScreenGui for a head-up display or a SurfaceGui if you want the clock to exist on a part in the 3D world.
If you're going with a HUD, just pop a ScreenGui into StarterGui, add a TextLabel, and name it something like "TimeLabel." If you want a physical clock, create a part, add a SurfaceGui to one of its faces, and put your TextLabel inside that. It's the same logic for both, which is the beauty of how Roblox handles UI.
One thing I always recommend is to style your TextLabel a bit before you start scripting. Pick a font that matches your game's vibe—maybe something blocky for a sci-fi game or something elegant for a simulator. It makes the testing process a lot more satisfying when the clock actually looks good.
Writing the Basic Script
Now for the meat of the project. We're going to use a LocalScript if the clock is just for the individual player's UI, or a regular Script if you're trying to sync the time across the whole server. For most "game time" scenarios, a server-side script is better so everyone sees the same time.
In your script, you're going to want to use a loop. But please, don't use a while true do loop without a task.wait(). That's a one-way ticket to crashing your Studio. We want the clock to update frequently enough to look smooth, but not so fast that it eats up performance. Updating once per second is usually plenty.
You'll be looking at the Lighting service a lot. Specifically, the ClockTime property. This property is a number between 0 and 24. For example, 13.5 means it's 1:30 PM. To turn that number into a string of text that a human can actually read, we have to do a little bit of math.
Formatting for Humans (12 vs 24 hours)
This is where people usually get a bit tripped up. Taking a decimal like 14.25 and turning it into "2:15 PM" takes a couple of steps. First, you isolate the hours by flooring the number. Then, you take the remainder, multiply it by 60, and that gives you your minutes.
If you're a fan of military time (24-hour format), your job is pretty much done. But if you want a standard 12-hour clock with AM and PM, you'll need an if statement. If the hour is greater than 12, subtract 12 and set a variable to "PM." If it's 0, call it 12 AM. It sounds a bit tedious, but once you write it once, you can just copy-paste it into any future project.
Another pro tip: use string.format to make sure your minutes always have two digits. There's nothing that looks more amateur than a clock that says "4:5 PM" instead of "4:05 PM." Using "%02d" in your string formatting will handle those leading zeros for you automatically.
Connecting the Clock to the Sky
A roblox custom clock script is even cooler when it actually drives the environment. If you want your game's sun and moon to move in sync with your UI clock, you'll want to increment the Lighting.ClockTime within your loop.
Let's say you want a full day-night cycle to last 20 minutes in real life. You'd figure out how much the ClockTime needs to change every second to make that happen. It's just a bit of division. Once you have that "time step" value, you just add it to the current time every second. Now, when your UI says it's midnight, your game world will actually be dark. It creates a much more immersive experience for the players.
In-World Clocks vs. UI Clocks
If you're building a physical clock—like a watch on a character's wrist or a big clock tower in the town square—you might want to skip the TextLabel entirely and use moving parts. This is a bit more advanced but looks amazing.
Instead of changing text, your script would rotate the "hands" of the clock. You'd use CFrame.Angles to spin the hour hand and the minute hand based on the current time. The math is similar—you're just converting the time into degrees (0 to 360) rather than strings of text. It's a small detail, but players really notice when the hands on a wall clock actually move correctly.
Making It Look Good
Don't settle for a plain white box. Once you have the logic working, spend some time on the "juice." You could add a slight glow to the text if it's a digital clock, or maybe have the color change slightly depending on the time of day. Perhaps it turns a soft orange during sunset and a cool blue at night.
Using UIGradient is a quick way to make your clock look professional. You can also use TweenService to make the numbers fade in or out when the time changes, though for a clock that updates every second, simple text changes are usually fine. If you're feeling fancy, you can even add a ticking sound effect that plays every time the second hand moves. Just make sure the sound is subtle, or it'll get annoying pretty fast.
Common Mistakes and Fixes
One mistake I see all the time is scripts that run way too fast. You don't need your clock to update every single frame (Heartbeat). That's just a waste of resources. Unless you're showing milliseconds for a racing game, task.wait(1) is your best friend.
Another issue is time desync. If you run the clock logic entirely on the client (the player's computer), different players might see different times if they joined at different moments. To fix this, always calculate the time based on the server's os.time() or a value stored in a NumberValue in ReplicatedStorage. That way, when one player says, "Meet me at the fountain at 8 PM," everyone is looking at the same 8 PM.
Lastly, watch out for the 24-to-0 jump. When your time reaches 24, you need to make sure it resets back to 0 cleanly. Most of the time, Roblox handles this naturally with ClockTime, but if you're using your own custom variables, you'll need a simple if time >= 24 then time = 0 check.
Wrapping It Up
Building a roblox custom clock script is one of those projects that feels really rewarding because the results are so visible. It's a perfect blend of UI design and logical scripting. Once you get the hang of the Lighting service and basic string formatting, you can customize your clock to fit literally any genre.
So, go ahead and give it a shot. Start simple with a basic TextLabel and work your way up to a full day-night cycle with rotating clock hands. It's those little details that really separate a hobby project from a polished game that players want to spend time in. Happy scripting!