What Is a 9-Segment Display? 9 vs 7, 14 and 16-Segment Displays

Last updated: September 24, 2026

Most engineers know the 7-segment display, and many know the 14- and 16-segment alphanumeric types. The 9-segment display gets less attention. Think of it as a 7-segment digit with two extra diagonal segments: the figure-8 stays exactly as it is, two diagonals go inside it, and there is usually a decimal point (DP) as well. Those two diagonals let each digit draw a few strokes a 7-segment digit cannot, and the wiring stays much simpler than a 14- or 16-segment display. The name counts the light-emitting segments in one character and leaves out the decimal point, the same way 7-segment and 16-segment are counted.

What does a 9-segment display look like?

Start with the figure-8 everyone knows from a 7-segment digit: top, middle and bottom bars, and two vertical segments on each side. A 9-segment display keeps all seven and adds two diagonals inside the figure-8, one in the upper half and one in the lower half. The round decimal point sits at the lower right, in the same place as on 7-segment and 16-segment displays.

Take our OPD-S5030(1) 0.5″ single-digit 9-segment display as an example. It uses this layout, with diamond-cut segments. If names like 7-segment, 14-segment and 16-segment are new to you, or you want to see how the segments are wired inside the package, start with Inside a 7-Segment Display: Internal Structure & Pinout.

9-segment vs 7-segment vs 14-segment vs 16-segment displays

More segments per digit means more characters you can draw. It also means more pins and more driver outputs, and that cost should be counted together when you select a display. The table puts the four common layouts side by side.

So which characters can a 9-segment digit actually show? The three example images below cover Arabic numerals, uppercase letters and lowercase letters, followed by a truth table engineers can work from when writing the driver code. For 7-segment and 16-segment displays, the full truth tables are in 16-Segment vs 7-Segment Displays: What Each Can Show.

Start with the Arabic numerals 0 to 9. They look exactly the same as on a 7-segment digit and neither diagonal is used, so a font written for a 7-segment display carries straight over.

Next, capital letters. A 9-segment digit can show 16 of the 26. A, C, E, F, G, H, I, J, L, O, P, S and U can also be drawn on a 7-segment digit. N, Q and R are the ones the diagonals make possible: N is the two side segments joined by the full H+I diagonal, Q is an O with the lower diagonal (I) as its tail, and R is a P with I as its right leg. Note that I, O and S come out identical to 1, 0 and 5, but inside a word (LINE, OPEN, CLOSE) they still read correctly, and the 7-segment article uses them the same way, so they stay. B and D are different: B is simply an 8, and D cannot be told apart from 0 or O, while lowercase b and d are easy to read, so the uppercase forms are marked N/A and the lowercase ones are used instead. K, M, V, W, X, Y and Z need a diagonal in the / direction, and T needs a centre bar. A 9-segment digit has neither, so those letters call for a 14- or 16-segment display.

Lowercase letters do better: 20 of the 26, because many lowercase letters only use the lower half of the figure-8. b, c, d, n, o, r and u can already be drawn on a 7-segment digit. The one the diagonal adds is k: the left-hand segments and the middle bar, with the lower diagonal (I) as the angled leg. g looks the same as 9 and s the same as 5, so the reader relies on context. Lowercase l uses the left-hand segments, which keeps it apart from the number 1 and capital I on the right, and y gets a bottom bar so it does not look like a 4. There is no usable lowercase f, so an uppercase F is used instead. As with uppercase, m, v, w, x and z need a / diagonal or a centre bar, so they are N/A.

As on a 7-segment display, words on a 9-segment display usually mix upper and lower case: letters that do not work in uppercase are filled in with lowercase, such as b, d and t, while N and R, which a 7-segment digit struggles with, can be shown in uppercase. This works for a fixed set of short words decided in advance, such as OPEN, CLOSE, ON or OFF; check each one against the two images above. If the text cannot be chosen in advance, for example anything the user types in, go to a 14- or 16-segment display.

Finally, the truth table. It uses the same format as the 7-segment one: one row per character, one column for each of the nine segments A to I, and a V where the segment lights (V : TURN ON LED), with the segment drawing and the OPD-S5030 and OPD-S5031 pin numbers at the top right. It lists 0 to 9 plus N, Q and R, the characters that use the diagonals. The other letters do not touch the diagonals and are mostly written the same way as in the 7-segment truth table. For lowercase k, light E, F, G and I.

When should you choose a 9-segment display?

In short, the 9-segment display sits between the 7-segment and the alphanumeric families. The product mostly shows numbers, but the interface needs one or two characters or symbols a 7-segment digit cannot draw, and a 14- or 16-segment display would add segments, pins and driver outputs the design never uses. In that case, 9-segment is the more economical choice.

• 7-segment: the display only needs numbers and a few simple letters, such as a timer, a counter or a temperature readout.
• 9-segment: mostly numeric, with a few diagonal strokes a 7-segment digit lacks. Before you decide, take the segment drawing from the datasheet and check it against every character you plan to show, one by one.
• 14-segment: the display must spell words in uppercase, for example menu names or scrolling status messages. Our 14-segment range is SMD, which suits compact, reflow-soldered boards.
• 16-segment: you need uppercase plus most lowercase letters, or a larger through-hole character that can be read from a distance. Our 16-segment range goes up to a 2.2″ single-digit display.

One more reminder: a 9-segment display cannot show the complete A-Z alphabet. If the character list keeps growing during design, it is better to move to a 14- or 16-segment display early than to work around missing strokes, because a board change later costs more. You can compare every size and digit count on our alphanumeric LED display page.

OPD-S5030(1) 9-segment display specifications

The OPD-S5030(1) is a single-digit 9-segment display with a 0.5″ (12.7 mm) digit height and diamond-cut segments. It is a through-hole (THT / DIP) part, 18.90 mm x 12.60 mm, 8.00 mm thick. All seven colors are tested at 20 mA.

Of the seven colors, Pure Green is the brightest at 250 mcd. Note that the forward voltage falls into two groups: Blue and Pure Green need about 3 V, while Red, Orange Red, Amber, Yellow and Yellow Green run at about 2 V. So when you change color, recalculate the current-limiting resistor instead of reusing the old value. The datasheet for each color is on the product page. If you want to know what each column on a datasheet means, see How to Read an LED Specification Table. If you have not settled on a color yet, we covered how the cost differs between emitting colors in How to Choose the Lowest-Cost LED Color for Your Product.

9-segment display FAQ