Why the numbers are worth ten minutes
A specification sheet is the only written record of what you are buying. Quotations change, sales calls are forgotten, and the sheet is what arrives at site. That makes it worth checking before anyone signs.
The check does not need specialist software. Most LED display sheets are internally consistent or internally contradictory, and two arithmetic relationships expose which one you are holding. Both come from the geometry of the panel, so they hold whatever the supplier claims.
The practical reason to do it early is that errors compound. If the pixel density figure is wrong, the brightness per square metre, the power load and the viewing distance recommendation built on top of it are all unreliable too.
The two checks that cover most of a sheet
The first is pitch. Pixel pitch equals module size divided by module pixel count, and it should come out the same on both axes. A module listed as 320 by 160 mm with 64 by 32 pixels gives 320 divided by 64, which is 5.0 mm, and 160 divided by 32, which is also 5.0 mm. Both axes agree, so the pitch figure of 5.0 mm is sound.
The second is density. Pixel density equals total pixels divided by area in square metres. The same module holds 64 times 32, which is 2,048 pixels, over an area of 0.32 by 0.16, which is 0.0512 square metres. Dividing gives 40,000 pixels per square metre.
Run both checks on every line you care about. They take about a minute each and they do not require the supplier to confirm anything, because both relationships are geometric. There is nothing commercial to confirm.
Where sheets most often disagree with themselves
The common cause is a mix-up between module figures and cabinet figures. A module is the small serviceable tile; a cabinet is the assembled frame holding several modules. Both have sizes and both have pixel counts, and a sheet that labels one with the other's numbers will fail the pitch check immediately.
The second cause is a straightforward transcription error. One widely circulated indoor sheet lists a 1.875 mm module as 128 by 64 pixels, which gives 1.875 mm across one axis and 3.75 mm across the other. The density figure on the same line, 284,442, only reconciles with 128 by 128. The pixel count was mistyped; the density was right.
The third cause is units and labels. Brightness written as cdm² should read cd/m². Sheets that put a distance in metres under a heading asking for an angle, or the reverse, are more common than they should be, and they make a viewing recommendation impossible to read correctly.
Module figures and cabinet figures
Transparent LED screens show how confusing this gets. One sheet describes a 3.91 mm product with a module of 500 by 125 mm carrying 256 by 64 pixels. Run the pitch check and you get 1.95 mm, which contradicts the 3.91 mm headline.
The figures only reconcile once you read them as cabinet dimensions. A cabinet of 1,000 by 500 mm with 256 by 64 pixels gives 3.906 mm across and 7.812 mm down, matching the stated 3.91 and 7.82, and the density of 32,768 per square metre resolves as well.
The lesson is not that the sheet was dishonest. It is that you have to establish which physical unit a row describes before you can check anything on it. Ask that question first, and the rest of the sheet becomes readable.
Read brightness, power and viewing range as ranges
Realistic sheets give intervals instead of single figures, and that is a sign of quality. A single figure on a sheet that depends on drive current is a figure somebody chose. Indoor modules commonly sit between 600 and 1,500 candelas per square metre depending on lamp type and drive current. Outdoor modules typically run from 3,500 up to 7,500, because direct sun demands a different order of output.
Power follows the same pattern and matters more than buyers expect. Indoor products cluster around 400 watts per square metre average and 800 peak. Outdoor products tend to run 450 to 500 average and 800 to 1,000 peak. Those numbers decide cable sizes, breaker capacity and heat load, so a range is more useful than a single figure.
Viewing distance on a sheet is a recommendation, not a hard limit. The stated range reflects where the pixel grid stops resolving for most people, and it moves with content type. Dense text needs a shorter distance than video, and the sheet rarely says so.
When a number is missing
Some sheets carry a line such as parameters available on request. Treat that as information, not as an oversight to be worked around. It usually means the configuration is not fixed, or the product is still being finalised, and either way you cannot design around it.
Ask for the figure in writing before you commit to anything that depends on it. Cabinet weight and thickness, maintenance access, and peak power are the three that most often sit behind that line, and all three change what the structure and the electrical design have to carry, not only what the screen does.
If a supplier cannot put a number in writing, the honest read is that the number is not settled. Plan for the upper end of the range and make the final value a condition of the order.
A ten-minute checklist
Confirm for each row whether the size given is a module or a cabinet. Divide size by pixel count on both axes and check both match the stated pitch. Multiply total pixels and divide by area to confirm the density figure.
Check that brightness carries units of cd/m² and that power distinguishes average from peak. Confirm whether the ingress rating applies to the front only or to both faces, because outdoor installations need both.
Finally, list every figure you still need and send it back as one written request. One consolidated question gets a faster and more accurate answer than six separate emails, and it leaves you with a document to check the delivery against.
A transcription error exposed by the pitch check
One circulated indoor sheet lists a 1.875 mm module as 128 by 64 pixels. The maths gives 1.875 mm on one axis and 3.75 mm on the other. The contradiction is the signal that the row was copied wrongly.
Transparent screens need the cabinet read
A 3.91 mm transparent product with a 500 by 125 mm module carrying 256 by 64 pixels yields 1.95 mm and 3.91 mm, which does not match the stated pitch. The numbers only reconcile when read as a 1,000 by 500 mm cabinet with 256 by 64 pixels, giving 3.906 mm across and 7.812 mm down.
Applying this on site: read an led display specification sheet
- Run the pitch check Divide module size by module pixel count; the result must match on both axes. A 320 by 160 mm module with 64 by 32 pixels gives 5 mm across and 5 mm down, which is internally consistent. When the two axes disagree, the rest of the sheet is suspect.
- Run the density check Divide total pixels by area in square metres. The same module holds 64 times 32, which is 2,048 pixels, over an area of 0.0512 m2, giving about 40,000 pixels per square metre. Both relationships are geometric, so neither needs the supplier to confirm anything.
- Establish the unit before you check Most contradictions come from mixing module figures with cabinet figures, or metres with angles. State which physical unit each row describes before checking anything on it; the figures only reconcile once the unit is fixed.
Beliefs worth rechecking on read an led display specification sheet
“A single brightness or power figure is precise.” — Realistic sheets give ranges. A single figure on a specification that depends on drive current is a number someone chose; indoor modules cluster around 400 W/m2 average and 800 W/m2 peak, and outdoor products tend to run 450 to 500 average.
The decision in one line: read an led display specification sheet
Two arithmetic checks, pitch against module geometry and density against area, will tell you whether a specification sheet is trustworthy. Establish whether each row describes a module or a cabinet first, read brightness and power as ranges, and get any missing figure in writing before the order is placed.