1.8mm / 2mm Round Top LED

1.8mm / 2mm round top LEDs are the smallest through-hole (DIP) LEDs we stock.

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1.8mm / 2mm round top LEDs are the smallest through-hole (DIP) LEDs we stock. At just under 2mm in diameter, these micro-sized emitters are barely larger than the head of a pin, making them the go-to choice for applications where a standard 3mm LED would be too large or visually disproportionate. Scale modelers, miniature wargaming painters, jewelry makers, and micro-electronics builders choose 1.8mm LEDs specifically because the light source needs to be as invisible as possible while still producing a visible and convincing glow. We carry 1.8mm round top LEDs in every standard color: red, orange, yellow, green, blue, white (warm and cool), pink, and UV. Each product page lists the peak wavelength, forward voltage, brightness in millicandela, viewing angle, and maximum drive current so you can spec the part precisely for your circuit.

N and Z scale model railroading is the flagship application for 1.8mm LEDs. At N scale (1:160), a 2mm LED represents a roughly 320mm (12.5-inch) real-world light source — proportionally correct for building interior ceiling lights, station platform fixtures, yard lamps, and signal heads. At Z scale (1:220), the 2mm LED is appropriately sized for larger building windows and platform lights. These are applications where even a 3mm LED would look comically oversized against the tiny structures. N scale modelers use warm white 1.8mm LEDs for building interiors, white for platform and yard illumination, red and green for block signals and crossing gates, yellow for caution signals, and blue for emergency vehicle roof lights. The LED’s standard two-lead through-hole form factor makes it easy to solder to fine hookup wire, route through a building shell, and connect to the layout’s accessory power bus. For DCC layouts, add a bridge rectifier and smoothing capacitor to convert track power to DC, then add a current-limiting resistor and connect the LED. See the AC/DCC wiring guide for full details. For analog DC layouts with a 12V accessory bus, just add the appropriate resistor — use our LED resistor calculator to find the value.

Wargaming miniature painting (Warhammer 40K, Age of Sigmar, Malifaux, Infinity, BattleTech) is the second largest market for 1.8mm LEDs. Hobbyists drill tiny holes into resin and plastic miniatures and embed 1.8mm LEDs for glowing eyes on Space Marine helmets, weapon-barrel energy effects on Tau rail rifles and Imperial Knight arm cannons, cockpit instrumentation on Aeronautica Imperialis aircraft, and reactor glow effects on Titan and Knight chest plates. The 2mm diameter fits into a 2mm drill hole with minimal material removal, preserving the structural integrity of the miniature. Fine enamel magnet wire (30–36 AWG) routes through limbs and torso cavities to a battery pack hidden in the base. A coin cell (CR2032 at 3V) can drive a 1.8mm LED through a small resistor for hours of tabletop play. LED-illuminated miniatures consistently win painting competition awards for the dramatic visual impact they create on display.

Jewelry, watch modding, and wearable electronics are growing applications for 1.8mm LEDs. Custom jewelry makers embed 1.8mm LEDs in resin pendants, wire-wrapped rings, and ear cuff designs where the LED must be nearly invisible when off but produce a stunning glow when powered by a concealed coin cell. Watch modders replace or add indicator LEDs in custom watch faces, using 1.8mm emitters that fit behind dial apertures without interfering with movement components. Wearable electronics prototypes use 1.8mm LEDs on flexible PCBs for compact indicator arrays on smart textile projects, fitness bands, and cosplay accessory circuits where every millimeter of size reduction matters.

Micro panel indicators and test equipment represent the industrial application for 1.8mm LEDs. Dense control panels with many status indicators in a small area benefit from the 1.8mm footprint — you can pack more indicators per square centimeter than with 3mm or 5mm LEDs. Test jigs, calibration fixtures, and diagnostic equipment use 1.8mm LEDs for pass/fail indicator arrays where dozens of status points must be visible simultaneously in a compact enclosure. The 2mm body fits standard 2mm panel-mount LED holders and bezels for clean, professional-looking installations.

Electrical specifications for 1.8mm LEDs follow the same conventions as all our through-hole DIP LEDs. Forward voltage depends on color: red/orange/yellow/amber at approximately 2.0–2.2Vf; blue/green/white/UV/pink at approximately 3.0–3.2Vf. Maximum drive current is 20mA. The two leads have standard polarity: the longer lead is the anode (+), the shorter is the cathode (−). Viewing angle is typically 20–30° for the clear-lens round top body. Despite the small size, the LED die inside a 1.8mm LED is often the same chip used in 3mm and 5mm LEDs, so absolute light output is comparable — it is simply focused into a narrower viewing cone. A current-limiting resistor is required for all bare 1.8mm LEDs — use our LED resistor calculator to find the correct value for your supply voltage.

1.8mm vs. 0402 SMD: if you need an even smaller LED, our 0402 SMD LEDs measure just 1.0mm × 0.5mm — half the size of a 1.8mm DIP LED. The trade-off is that 0402 SMDs are surface-mount components requiring SMD soldering technique (or purchase our pre-wired SMD LEDs with leads already attached). The 1.8mm DIP LED has standard through-hole leads that are much easier to solder with a basic iron, making it the better choice for hobbyists who want the smallest possible LED without entering SMD territory. If your project can accommodate a slightly larger LED and you want even more brightness, our standard 3mm DIP LEDs are the next step up. New to LEDs? Our pre-wired LEDs come with the resistor already attached — just connect power and ground, no calculations needed.

Frequently Asked Questions

1.8mm LEDs are the smallest through-hole LEDs available, used primarily for N and Z scale model railroad lighting (building interiors, signals, platform lamps), Warhammer and wargaming miniature illumination (glowing eyes, weapon effects, cockpit instruments), micro jewelry and watch modding, wearable electronics, and dense indicator panels on test equipment. Any application where a 3mm LED would be too large or visually disproportionate calls for a 1.8mm.
A 1.8mm LED is about 60% the diameter of a 3mm LED and 36% the diameter of a 5mm LED. In practical terms, it is slightly larger than a pinhead. The lens body is roughly the width of two stacked credit cards. Despite the tiny size, 1.8mm LEDs are still through-hole components with standard wire leads, so they are much easier to solder than SMD LEDs. For an even smaller option, our 0402 SMD LEDs measure just 1.0mm × 0.5mm but require surface-mount soldering technique.
Yes. Like all bare LEDs, 1.8mm emitters require a current-limiting resistor to prevent overcurrent damage. Use our LED resistor calculator to find the correct value for your supply voltage and the LED’s forward voltage (listed on each product page). For a 3V coin cell (CR2032), the required resistor is small — often 47–100Ω. For 12V sources, a larger resistor is needed. If you want zero-math installation, our 12V built-in resistor LEDs and pre-wired LEDs include the resistor already.
Yes, but DCC track power must be converted to DC first. Add a bridge rectifier and smoothing capacitor, then connect the 1.8mm LED through a current-limiting resistor. See the AC/DCC wiring guide for the complete wiring diagram. For analog DC layouts, just add the appropriate resistor between your accessory power bus and the LED.
Yes — 1.8mm LEDs are the most popular through-hole LED size for miniature illumination. Drill a 2mm hole in the miniature (resin or plastic), insert the LED, and route fine magnet wire (30–36 AWG) through the body to a battery pack hidden in the base. A CR2032 coin cell (3V) through a small resistor drives the LED for hours. Popular effects include glowing helmet eyes, weapon-barrel energy glow, cockpit instruments, and reactor effects. For even smaller emitters that require no drilling, our 0402 SMD LEDs can be surface-glued directly.
A 1.8mm DIP LED is a through-hole component with two wire leads — easy to solder with a standard iron. An 0402 SMD LED is a surface-mount component measuring just 1.0mm × 0.5mm with no leads — it must be soldered to PCB pads using SMD technique (or buy our pre-wired SMD LEDs with leads pre-attached). The 0402 is roughly half the size of a 1.8mm DIP but much harder to work with. Choose 1.8mm DIP if you want the smallest LED you can solder with a basic iron. Choose 0402 SMD if absolute minimum size matters and you have SMD soldering capability.