Light Bulb Base and Size Guide

U.S. Voltage & Power Standards

Before selecting a base, verify the electrical supply of the fixture. Residential, landscape, and industrial applications in the USA utilize three distinct voltage tiers.

Tier 01: Residential 🏠 120V Line Voltage

The standard for American homes. Powers E26 bulbs, GU10 track lights, and integrated LED ceiling fixtures.

Tier 02: Low Voltage 12V Low Voltage

Requires a transformer. Primary standard for MR16 track lighting, under-cabinet pucks, and landscape path lights.

Tier 03: Industrial 🏭 277V Commercial

Common in US warehouses and office troffers. Essential for T8 linear tubes and high-bay warehouse LED retrofits.

Professional Base Directory

Click any base below to browse our specific collection of LED replacements.

U.S. Shape & Size Matrix

Identify your bulb's shape and diameter code (Diameter in 1/8ths of an inch). Use the links below to shop the exact profile.

Shape Profile US Diameter Typical Voltage Action
A19 (Standard Pear) 2.375" 120V Shop A19
B10 / CA10 (Bullet) 1.25" 120V Shop B10
G25 (Vanity Globe) 3.125" 120V Shop G25
BR30 (Indoor Flood) 3.75" 120V Shop BR30
PAR38 (Outdoor Flood) 4.75" 120V Shop PAR38
T8 (1" Linear Tube) 1.0" 120-277V Shop T8
MR16 (Track Spot) 2.0" 12V / 120V Shop MR16