7-Segment Display Decoder
Enter 0–F and see which segments light up — common-cathode and common-anode both supported.
What it does: Translate a digit into which 7-segment display segments light up.
When to use it: When driving a 7-segment display, looking up segment codes, or building an MCU display.
MEANS The lit segments form the displayed glyph; the segment bit string can go straight into an MCU segment lookup table.
No history yet. Each calculation is automatically saved to this device.
How to use the 7-segment decoder
Enter a digit, see the segments.
- 01
Enter a digit
0–9 or hex A–F.
- 02
Pick the drive type
Common-cathode (1 = lit) or common-anode (0 = lit).
- 03
See which segments light up
Shows visually which of segments a–g are on, plus the segment bit string and hex.
Common questions, answered in 3 minutes
How do I tell common-cathode from common-anode?
On a common-cathode display all segment cathodes go to ground, so a HIGH on a segment lights it; on a common-anode display all anodes go to VCC, so a LOW lights a segment. Pick the wrong drive direction and the digit stays dark or lights up entirely.
How are segments a–g laid out?
Top bar = a, top-right vertical = b, bottom-right vertical = c, bottom bar = d, bottom-left vertical = e, top-left vertical = f, middle bar = g. This tool follows that standard.
How do I show the decimal point?
Most displays have an 8th segment DP (decimal point) driven by its own pin; this tool only illustrates the main 7-segment body.
Standards and sources referenced by this tool
| Item | Value / Formula | Source |
|---|---|---|
| Segment map | a–g standard layout | Common 7-segment convention |
Standard a–g segment map, no external API.