Inner Diameter – What It Means for Coil Builds & Vape Performance

Definition

Inner Diameter (often shortened to I.D.) is the internal width of a vapecoil, measured in millimetres across the centre of the coil. It dictates how much cotton wick can pass through and how much surface area is available for e-liquid to vaporise. A larger inner diameter produces more vapour and a looser draw, while a smaller one intensifies flavour and gives a tighter, cigarette-like Inhale Style. For rebuildable atomisers, the inner diameter also influences ramp-up time and battery strain, making it a critical variable for both beginner and advanced Australian vapers.

Technical Details

How It Works

The inner diameter of a coil directly affects its electrical resistance. Using the same Wire Type”>wire type and coil height, a 3 mm I.D. coil will read lower in ohms than a 2 mm I.D. coil because the wire length increases as the diameter grows. Common I.D. sizes range from 2 mm to 4 mm in rebuildables, while stock IGET pods and other closed-system devices use proprietary micro-coils often below 1.5 mm. Measured with precision callipers or coil rods, the I.D. must remain consistent to avoid hot spots or uneven wicking. Variations include half-millimetre steps (2.5 mm, 3.5 mm) and specialty sizes for mesh strips.

Common Specifications

• 2 mm: Best for high-nicotine salts and tight MTL draws.
• 2.5–3 mm: Balanced flavour & vapour for restricted DL.
• 3.5–4 mm:Cloud chasing and low-resistance builds.
• 4 mm+: Rare; used in stacked coils or exotic builds.

Usage & Tips

Practical Guidance

Choose your inner diameter based on your Inhale Style and device power. If your integrated batterymod caps at 60 W, stay between 2.5 mm and 3 mm to avoid overloading the internal battery. Always check that cotton fills the coil snugly—if it slides through without resistance, the I.D. is too large and may leak or spit. Conversely, jam-packed wicks choke airflow and mute flavour. When rebuilding, use ceramic rods or coil jigs to keep the inner diameter perfectly round and prevent shorts against the insulator.

History & Context

Early cig-a-like coils from 2010 had an inner diameter under 1 mm, limiting vapour and flavour. The rise of sub-ohmvaping in 2014 pushed diameters past 2.5 mm, and today’s high-wattage devices commonly use 3 mm–4 mm coils. Australian regulations on nicotine imports have increased DIY coil building, making inner diameter knowledge essential for safe, cost-effective vaping.