Luminance Converter for Nits Stilbs and Lamberts Online

Screen specifications quote brightness in nits, older lighting literature uses lamberts, and physics texts still mention stilbs. When the same quantity wears three different names, comparing two values turns into a small research project. A luminance converter removes that friction: enter a value in one unit and read it immediately in the others, so a display spec, a projector figure and a textbook number can finally be weighed against each other.

Understanding Luminance and Its Units

Luminance describes how bright a surface appears to the eye, measured as light intensity spread over an area. The standard unit is the candela per square metre, written cd/m², and in the display industry the very same unit is nicknamed the nit: one nit equals exactly one candela per square metre. The stilb is an older metric unit equal to one candela per square centimetre, which makes it ten thousand times larger than a nit. The lambert, named after the physicist Johann Heinrich Lambert, is also built on the square centimetre and equals about 3,183 candela per square metre.

Luminance is not the same as illuminance. Illuminance is the light falling onto a surface, measured in lux, while luminance is the light leaving that surface toward your eyes. If you are working with the incoming side of the equation, the Illuminance Converter covers lux and foot candles.

What This Luminance Converter Handles

• Three unit families: convert between candela per square metre (nits), stilbs and lamberts in either direction.
• Exact relationships: results follow the fixed definitions, 1 stilb = 10,000 cd/m² and 1 lambert ≈ 3,183.1 cd/m², so conversions are reproducible.
• Copyable results: the Copy button lets you lift the converted value straight into a report, spreadsheet or spec sheet.
• Decimal friendly: small values, common with lamberts, and large ones, common with stilbs, are handled without rounding away the detail you need.

Steps to Convert a Luminance Value

1. Find the value you need to convert and note which unit it was published in.
2. Enter the number in the converter and select that unit as the source.
3. Select the unit you want to compare or report in.
4. Click Convert and read the result.
5. Click Copy if you need the figure in a document or calculation.
6. For a second comparison, change the target unit and convert again from the same starting value.

A Worked Example With a Laptop Screen

Suppose a laptop panel is rated at 300 nits and you need that brightness in lamberts for an older reference table. Dividing 300 by 3,183.1 gives about 0.0942 lamberts. In stilbs the same screen is 300 divided by 10,000, which is 0.03 stilbs. Running the numbers the other way, a cinema era figure of 10 lamberts equals roughly 31,831 nits, which shows how much brighter the lambert scale's everyday numbers are compared with the screen values most people meet today.

Conversions like these come up when calibrating monitors for video work, comparing projector output against screen gain figures, checking photographic exposure notes, or translating values between modern datasheets and older lighting handbooks. If your project also involves the physical dimensions of a screen or surface, the Area Converter handles the square metre side of related calculations.

Practical Advice, Limits and Frequent Errors

Mind the per area basis. The classic trap is mixing per square metre units with per square centimetre ones. A stilb is not a slightly different nit; it is ten thousand of them, and glossing over the area basis produces results that are wildly wrong while looking plausible.

Do not confuse brightness with light output. A lamp's total output in lumens and a screen's luminance in nits describe different things. This converter only translates between luminance units; it cannot turn a lumen figure into nits without knowing the area and direction involved.

Keep sensible precision. Display measurements themselves carry tolerances, so quoting a converted value to six decimal places implies accuracy the original measurement never had. Two or three significant figures are usually honest for real world work.

Luminance Questions Answered

Is a nit the same as a candela per square metre?

Yes. Nit is simply the informal industry name for one candela per square metre, so a 400 nit display has a luminance of 400 cd/m².

What is a stilb used for?

The stilb appears in older scientific and lighting literature. It equals one candela per square centimetre, or 10,000 cd/m², which is why everyday screen values look tiny when expressed in stilbs.

How many nits is a typical laptop screen?

Many everyday laptops fall roughly in the 250 to 400 nit range, while brighter models aimed at well lit rooms go higher. Converting a quoted figure lets you compare it fairly against other units in older references.

What is the difference between luminance and illuminance?

Illuminance is light arriving at a surface, measured in lux. Luminance is light leaving a surface toward the viewer, measured in candela per square metre. They are related but not interchangeable.

Why does the lambert conversion use an approximate number?

The lambert is defined through pi: one lambert equals 10,000 divided by pi candela per square metre. Because pi is irrational, the practical factor 3,183.1 is a rounded form of an exact definition.

One Brightness, Any Unit

Brightness figures should be comparable at a glance, whatever era or industry published them. This luminance converter bridges nits, stilbs and lamberts with the exact unit relationships, so the number in front of you is the one you can actually use.