Blur a number plate

Why a plate is worth covering

A registration number is a short public identifier attached to a specific vehicle, and in many places it can be tied back to a person or at least a neighbourhood through a chain of lookups, forums, and enthusiast databases. On its own that is usually harmless. Combined with the other things visible in the same photo, it stops being harmless.

The three situations where this consistently bites people are the same three every time:

• Marketplace listings. You photograph the car on your own driveway. The listing now shows the plate, the house, and roughly where you live, to everyone browsing.
• Dashcam uploads. Posting a clip of someone else’s bad driving publishes their plate to an audience that sometimes decides to go looking for them.
• Holiday and event photos. A hire car outside an apartment, with the rental sticker and the building number in shot.

Pixelate, do not blur

This is the single most important choice on this page. Number plates are engineered to be legible: bold characters, strong contrast against a plain background, consistent spacing, and a small fixed alphabet. Every one of those properties helps someone reconstruct the text from a weak cover.

A moderate Gaussian blur keeps the rough light and dark pattern of each character. With a known font and a known character set, that pattern narrows the possibilities dramatically, and a plate is short enough that a human can brute-force the rest by eye. Pixelation at a large tile size collapses whole characters into single flat blocks and leaves nothing to work from. A solid black bar leaves even less.

The same reasoning applies to any short high-contrast string, which is why card numbers get the same treatment.

Cover the whole plate, plus a margin

Place the box a little wider and taller than the plate itself. Two things sit just outside the characters and both give information away: the country or state identifier strip down one side, and the dealer frame or sticker around the edge, which often names the town where the car was bought.

Angled shots need extra care. A plate photographed from the side becomes a narrow parallelogram, and a rectangular box that looks like it fits in a small preview often leaves a sliver of the first or last character exposed at the corner. Zoom in before you export.

Do not forget the second plate. Most three-quarter shots of a car show the front plate clearly and a slice of the rear plate reflected in a window or visible through the cabin. Photos of a queue of traffic can contain a dozen plates, not one.

Plates in video need a different approach

On the Video tab you place a box and mark when the blur starts and stops. There is no automatic per-frame tracking, so a plate that moves through the frame is the hard case. Two workable options:

1. Make one box big enough to cover the plate’s entire path for the window it is visible. Cruder, but it cannot slip.
2. Chain several short timed blurs, repositioning the box as the vehicle moves. Cleaner, more work, and more opportunity to leave a gap.

Then watch the clip back at normal speed with your eyes on the plate rather than the box. Video is unforgiving here because any viewer can pause on the one frame you missed, and on a dashcam clip that frame is often the moment the car is closest to the camera and the plate is at its most readable.

Check the rest of the frame before you post

Once the plate is covered, look at everything else. House numbers and street signs, a school badge in a rear window, a parking permit with an address on it, a satnav screen showing home, and the reflection of the street in the paintwork. On a marketplace listing the plate is rarely the only identifying detail, just the most obvious one.

If the photo came from a phone camera rather than a screenshot, it may also carry GPS coordinates in its metadata. Exporting a new PNG from a canvas editor drops that, but it is worth understanding which files keep location data before you upload the original anywhere.