Screen Brightness Explained: What Nits Mean for Outdoor Work

If you read the screen outdoors for a good part of the day, buy brightness. As our own rough guide, around 700 nits or more reads in direct sun. Something from 500 to 699 nits copes with a bright day if you angle it. Below 500 nits is an indoor, cab and under cover screen for most of the year, and no brightness setting will lift it into direct sun. In our range that puts the Tuga A8 at 800 nits and the Tuga W8 at 700 in the first group, the Tuga A6 at 560 in the second, and the Tuga A10 at 350 and the Tuga WH6 at 400 in the third. The Tuga W10 does not list a brightness figure, so we do not give one.

What a Nit Is

A nit is a unit of brightness, properly called luminance. One nit is one candela per square metre of lit surface, and a candela is roughly the intensity of a single candle. The figure on a spec sheet is normally the panel's peak brightness.

One rough anchor: ordinary office screens and budget tablets are built for rooms, not roofs, while a rugged tablet sold as sunlight readable should be somewhere around 700 nits or above. If the seller cannot give you a number, treat "sunlight readable" as a slogan rather than a spec.

Why Sunlight Is Really a Reflection Problem

A screen is never going to outshine the sun. Daylight falling on a white page is many times brighter than any tablet panel. What you are actually trying to do outdoors is make the content on the screen stand out against the daylight reflecting off the front of the glass.

Think of the picture as two layers. The backlight pushes the image out through the glass. The sky pushes a reflection back off it. Your eye sees both at once. If the reflection is as bright as the image, you see a mirror with a faint picture behind it. If the image is clearly brighter than the reflection, you can read it. Brightness raises the first layer. Anti-reflective coatings, matte finishes and bonding the panel directly to the glass with no air gap all lower the second. Two screens with the same nits can behave quite differently in sun, and our spec sheets list brightness but not reflectance or coatings.

This is why a 350 nit screen can be perfectly good on a grey February morning and hard going on a south facing roof in June. The panel has not changed. The reflection has.

It is also why the quickest fix for a screen you cannot read is to change what it is reflecting. Turn so your body takes the sun and the glass reflects something dark rather than the sky, or put your own shadow across the screen, and the reflected layer drops to a fraction of what it was. A shoulder turn often does more than a brightness setting.

350 vs 800 Nits: What the Gap Means on Site

Eyes do not judge brightness in a straight line. 800 nits is about 2.3 times as bright as 350, though your eye reads it as a step up rather than a doubling, and in strong sun the reflection takes much of that advantage back. What the extra buys you is margin: the difference between reading a drawing with the sun over your shoulder and needing to find a wall to stand against.

These three bands are our own rule of thumb, not a standard:

• 700 nits and above. Readable in direct sun with the screen tilted sensibly. Still hard work at midday with the sun straight onto the glass, but you can get the job done without hunting for shade. The A8 is 800 nits and the W8 is 700.
• 500 to 699 nits. Fine on bright days if you angle the screen and keep it clean. In full sun you will be using your body for shade more often. The A6 is 560 nits.
• Below 500 nits. Good indoors, in a vehicle, in a site cabin and under cover. Outdoors in sun, readable only with effort. The A10 is 350 nits and the WH6 is 400.

The A10 Is 350 Nits

The A10 is the device in our Android range with the big screen: 10.1 inches at 1920 x 1200, which is the one to pick if you spend the day inside PDF plans, BIM viewers and spreadsheets. It is also 350 nits, and that is a real limit. On a bright day it belongs in the van, in a vehicle dock, in the site office or under a roof. Out on an open roof or a lawn in July, it will be harder to read than the A8, and no amount of resolution makes up for that.

The A8 at £379 has the brighter screen, a 10000mAh battery and glove mode, but at 1280 x 800 drawings need more zooming. The A10 at £449 has the Full HD screen and dual SIM 4G, but 350 nits and an 8000mAh battery. Mostly reading drawings under cover: the A10. In your hand outdoors most of the day: the A8.

The W10 is the other 10.1 inch device. We do not list a brightness figure for it, so we cannot say how it reads in sun. If you need to use it outdoors, check the screen in your own conditions before relying on it.

Glare, Fingerprints and the State of the Glass

Reflection is not only about the sky. A screen covered in fingerprints, dust and dried rain scatters light across the whole surface, and that haze sits on top of your content like a net curtain. Outdoors, a dirty screen throws away much of the advantage that extra nits give you. A cloth in the door pocket is the cheapest readability upgrade there is.

A few other things that help, in rough order of how much difference they make:

• Angle. Tilt until the reflection shows something dark, such as your jacket, rather than the sky.
• Light theme, not dark. In sunlight you want as much of the screen emitting light as possible. Dark text on a white background reads far better outdoors than white text on black. Switch the app to a light theme if it has one.
• Bigger text. Fine lines on a drawing vanish first in glare. Zoom in further than feels natural, or raise the system text size for the day.

Auto Brightness: Check It Exists, Then Watch the Lag

Auto brightness uses a light sensor to raise the backlight when it is bright and lower it when it is not. We do not list a light sensor on our spec sheets, so check the display settings on your device. If it is there, it is worth leaving on for a device that moves between a van, a building and a yard all day.

The caveat is lag. Walking out of a plant room into sun, the sensor can take a moment to catch up, and it may settle a notch below what you would pick. You can nudge the slider, or set it manually: high outdoors, low in the van.

Brightness and Battery

The backlight is usually the biggest single drain on a tablet. Running a panel at full brightness all day can cost a large share of the battery, which is why a tablet that lasts a full shift in a site cabin may be looking for a charger mid afternoon on a sunny roof.

That has a few practical consequences:

• Bigger batteries buy margin. The A8 carries 10000mAh behind its 800 nit screen and the A6 carries 10600mAh behind 560 nits. The A10 has 8000mAh. The Windows devices have smaller batteries: 5000mAh in the W8 and W10 and 4000mAh in the WH6. If you run a W8 at 700 nits outside all day, plan to charge it during the day.
• Dark mode will not save power on the IPS models (A10, WH6, W8, W10). The A6 and A8 do not list a panel type. Turning brightness down is what saves power.
• Charge on the move. The 12V DC Car Charger at £26 fits every device in the range. For the A8, A10, W8 and W10, the Vehicle Mounting Dock at £109 holds the tablet and keeps it charged on the road.

Cold makes all of this worse, because a cold battery delivers less than it holds. Our winter battery guide covers that side, including the one charging mistake to avoid.

Which Screen for Which Job

• Outdoors most of the day, Android: Tuga A8, £379. 8 inch, 800 nits, listed as sunlight readable, with glove mode and a 10000mAh battery.
• Outdoors most of the day, Windows software: Tuga W8, £629. 8 inch IPS at 700 nits, listed as sunlight readable, running Windows 11 Pro. Smaller 5000mAh battery, so charge during the day. At £250 more than the A8, only worth it if your software needs Windows; our Android or Windows guide helps you check.
• In and out of a pocket: Tuga A6, £299. 6.78 inch at 560 nits. The pocket option; on a bright day, angle it and use your body for shade.
• Drawings under cover, outside now and then: Tuga A10, £449. 10.1 inch Full HD at 350 nits. Pair it with the vehicle dock if it lives in the van.
• Windows in a pocket: Tuga WH6, £699. 6.5 inch IPS at 400 nits, in the indoor and cab band.
• Full ports and Ethernet: Tuga W10, £649. 10.1 inch IPS. No brightness figure listed, so check it in your own conditions before relying on it outdoors.

If you are not sure which of those is you, the which Tuga page asks a few questions and narrows it down, and for the wider picture of what a site does to a tablet, see our guide to the best rugged tablets for construction. Prices above are as listed, with no VAT to add, and delivery is free to UK addresses in 7 to 10 working days. For a quote on more than one device, use the contact form.