How Does Geofencing Time Tracking Work?
Geofencing draws a virtual boundary around a job site and checks a worker's phone location before allowing a clock-in. Here is how it works, and how Clox blocks off-site punches instead of only warning about them.
You have heard that geofencing can stop your crew from clocking in before they reach the job, or from a truck two blocks away. You want to know what that actually means before you put it in front of your people. This is the plain version. No jargon, no promises it cannot keep.
Geofencing time tracking has three parts: a virtual fence you draw around a location, a phone that reports where it is, and an app that checks whether the phone is inside the fence before it lets someone clock in. That is the whole idea. The rest is how each part behaves in the real world, where GPS is imperfect and phones lose signal.
The three parts, one at a time
1. The virtual fence
A geofence is a boundary drawn on a map. In practice it is a point (the job site) and a radius (how far from that point still counts as being on site). Draw a circle around a warehouse, and anyone standing inside that circle is inside the fence. Step outside it and you are not. The word sounds technical, but it is just a circle on a map with a job attached to it.
2. The phone that reports its location
The location comes from the worker's phone, using the same GPS chip that runs their maps app. When someone opens the app to clock in, the phone works out where it is and hands that position to the app. This is the part worth being honest about from the start: the app does not see the worker with its own eyes. It trusts the coordinates the phone reports. That matters, and we come back to it below.
3. The app that checks before the punch
When the worker taps to clock in, the app compares the phone's reported position against the fence. Inside the circle, the punch is allowed. Outside it, the app has a decision to make. Some tools let the punch through and quietly add a note. Others block it. What a tool does at that moment is the real difference between one geofencing product and another.
How Clox implements it
Clox is time tracking for field and trade crews. One-tap clock-in, overtime and breaks calculated automatically, and payroll-ready exports for QuickBooks, Gusto, ADP, and Paychex. Geofencing is one setting on top of that, and here is how it behaves.
You draw a radius around each worksite
In Clox, a manager draws a radius around a job site on a map. That is a worksite. The radius is per worksite and you can adjust it, with a sensible default around 200 meters. A tight urban lot and a sprawling yard do not need the same circle, so you set each one to fit.
You choose who it applies to
Enforcement is per employee. You decide which crews the geofence applies to. A framer who stands on one site all week can be held to the fence, while a service tech who hits six addresses a day is left free so the tool does not fight them all day. You are not forced to switch it on for everyone or no one.
Off-site clock-ins are blocked, not just flagged
This is the part that separates Clox from tools that only warn. When the geofence is enforced for a worker and they try to clock in from outside the fence, Clox blocks the punch at the moment it happens. The off-site punch is never created. There is no bad record to catch later at approval, because it was never written. Most other tools let the clock-in through and leave a note for you to find. Clox stops it at the door.
There is an accuracy grace for honest near-misses
GPS is not exact, so a hard line at the edge of the circle would punish honest workers standing right at the fence. Clox handles this with a grace based on the accuracy the phone reports. A punch just outside the radius can still land if it falls within the phone's own reported accuracy, capped at 100 meters. Those allowed-but-marginal punches are flagged for you with an "Off the worksite" readout, so you can review them at approval instead of arguing about them in the field. A fix too coarse to trust, worse than about 500 meters or wider than the fence itself, is rejected as too inaccurate to make a call on.
It works offline
Job sites lose signal. When a phone is offline, Clox saves the punch on the device with its real timestamp, and the geofence is checked at the moment of the punch, not later. When signal returns, the punch syncs. The location check does not wait for a connection, so a dead-zone basement does not become a loophole.
Review flags surface the punches worth a second look
When a punch is allowed but something about it is off, Clox raises a flag for you to see at approval. There are three, in priority order:
- mock_location: the device reported a fake or mock GPS provider, which is the signal you care about most.
- impossible_travel: the punch is impossibly far from the same worker's previous punch, given the time between them.
- low_accuracy: a coarse but in-fence fix that was allowed and is worth a glance.
You are not sifting every punch. The clean ones stay quiet, and the flags point you at the handful that deserve a question.
Kiosk mode uses a shared tablet and a PIN, with no GPS
Not every crew clocks in from a personal phone. Clox has a kiosk mode: a shared tablet mounted on site where each worker punches with a PIN. Kiosk mode captures no GPS at all. Identity there comes from the on-site tablet plus the worker's PIN, not from location. If the tablet is bolted to the site trailer, the location is settled by where the tablet is.
Be honest about what geofencing can and cannot do
Geofencing is a strong deterrent. It is not a guarantee, and any tool that tells you otherwise is overselling. Here is the honest boundary.
The location comes from the worker's phone. The app trusts what the phone reports. A determined person can try to feed the phone a fake position, and no consumer app can promise it will catch every attempt. What Clox does is make that hard and make the attempt visible: off-site punches are blocked outright, a reported mock-location provider raises the mock_location flag, and a jump that is physically impossible raises impossible_travel. That turns casual fudging into a real effort that leaves a trail. It is a deterrent that changes behavior, not a tamper-proof seal.
If you want the deeper comparison of what location data can and cannot prove, the time-theft guide walks through where the real leaks are and which ones geofencing actually closes.
Common questions
Does the app track my crew all day?
No. Clox checks location at the punch, when someone clocks in or out. It is not following the phone around between punches. The point is to confirm a clock-in happened on site, not to watch anyone through the workday.
What happens if a worker is right at the edge of the site?
That is what the accuracy grace is for. A punch just outside the radius can still land if it falls within the phone's reported accuracy, up to 100 meters, and it is flagged for you to review. An honest worker standing at the fence line gets clocked in. You still see that it was close.
What if there is no cell signal on site?
The punch is saved on the phone with its real timestamp, the geofence is checked at that moment, and it syncs when signal returns. Losing signal does not skip the check and does not shift the time.
My techs drive between sites all day. Will this get in their way?
Only if you turn it on for them. Enforcement is per employee, so you can leave your mobile crews unfenced and apply the fence only where people stay put. Geofencing is a tool you point at the situations that need it.
Do I have to give everyone a company phone?
No. Workers can clock in from their own phone through a browser at app.getclox.com, and the iPhone app is available on a TestFlight beta. If you would rather not involve personal phones at all, kiosk mode with a shared tablet and PINs covers the crew from one device on site.
Trying it on your own sites
The fastest way to understand geofencing is to draw one circle around a real job and watch a clock-in behave. Clox is free for 14 days, with no credit card to start and a 30-day money-back guarantee. You can start a free trial and set up your first worksite in a few minutes, and the plans are on the pricing page if you want to see them first. If you run mixed crews, the field-crews guide covers the rest of what Clox does beyond the fence.