HUD speedometer guide

Written by Muneeb Rana · Last updated 26 October 2026

Quick answer: This HUD speedometer guide explains heads-up displays: what they are, how factory HUDs work, how a phone app mirrors its screen so the reflection reads correctly on the windscreen, and how to set one up at night. It links our HUD articles, the HUD mode feature and a comparison of HUD speedometer apps.

TL;DR

• What a HUD is.
• Phone mirror mode.
• Night setup.
• App comparison.
• Safety.

HUD speedometer guide: articles

• Speedometer HUD mode for your windshield: Speedometer PRO's speedometer HUD mode mirrors the display so your speed reflects on the windshield at night. How it works, setup and its limits.
• How to use HUD mode: How to use HUD mode in a speedometer app: mirror the display, place the phone under the windscreen, cut glare and night reflections, and stay safe.
• What is a HUD?: What is a HUD? A head-up display projects information into your line of sight. How car HUDs, aircraft HUDs and phone HUD apps work, and their limits.
• HUD display for car: your options: HUD display for car options compared: built-in HUDs, OBD and GPS plug-in units, and free phone HUD apps, with honest pros, cons and safety notes.

Feature and comparisons

• Speedometer HUD mode for your windshield: Speedometer PRO's speedometer HUD mode mirrors the display so your speed reflects on the windshield at night. How it works, setup and its limits.
• Best HUD speedometer apps: Best HUD speedometer apps: which App Store apps mirror speed onto your windscreen, with trip and alert features, checked 26 Oct 2026.

How mirror mode works

A windscreen reflects the phone's screen like a mirror, flipping it left to right. HUD mode pre-flips the display so the reflection reads normally. Because the glass is angled and laminated, you may see a faint double image; HUD films reduce this by giving a single reflective layer.

Factory HUD vs phone HUD

Factory head-up displays project an image that appears to float some distance ahead of the car, so your eyes need less refocusing. A phone reflection appears on the glass itself and is dimmer in daylight. It is a simple, low-cost approximation, best at night.

Before you drive

Set brightness to maximum, lay the phone on a non-slip mat where it won't slide under braking, and keep it clear of airbag deployment zones and the driver's view of the road.

Is a phone HUD legal?

Rules vary. Some places restrict anything placed on the dashboard or windscreen that blocks the driver's view, and some have rules about screens visible to the driver. A phone lying flat on the dash usually doesn't block the view, but check local law and keep the phone secured.

Tip

HUD works best at night with the phone flat on a non-slip mat, brightness up.

Related: Speedometer PRO: a GPS speedometer app with HUD and trip stats · GPS speedometer guide · Odometer guide: odometers and trip meters

Get Speedometer PRO on Google Play · Download on the App Store · Set it up before you move; never handle your phone while driving.

Sources

• Head-up display (Wikipedia): en.wikipedia.org (accessed 26 October 2026)