Despite all the comments around here about 9mm or 11mm not existing, I’ve used every size from 8mm to 19mm. And no question things have changed over time, too - those 12mm became more useful with Japanese cars, and the 16mm flange head bolt rather than 17mm plain hex is more a thing today than years ago. But if I ever need a 61mm I will probably use a Creacent…
I got curious and asked Gemini AI ; I am going to put this in my toolbox. I have all the sizes, but you only use a few on any particular job. I agree with you that you need every wrench.
common __________ metric wrench sizes
European = 8mm, 10mm, 13mm, 15mm, 17mm, and 19mm. The 10mm and 13mm sizes are arguably the most essential for modern vehicles.
American = 8mm, 10mm, 12mm, 13mm, 14mm, 15mm, 17mm, 19mm, 21mm, and 24mm. The "must-have" sizes for everyday tasks are 10mm, 12mm, 13mm, 15mm, and 17mm
Asian Japanese = 8mm, 10mm, 12mm, 14mm, 17mm, and 19mm the "must-have" sizes for everyday tasks are 10mm, 12mm, 13mm, 15mm, and 17mm. Other common sizes include 13mm, 15mm, 21mm, and 24mm
Chinese =
10mm, 13mm, and 17mm
Here are the common metric wrench sizes, typically categorized by usage:
1. Essential Daily-Use Sizes (8-19mm)
These are the most common sizes for general maintenance, bicycles, furniture, and smaller automotive parts:
- 8mm (Common for M5 nuts/bolts)
- 10mm (Extremely common, M6 fasteners)
- 12mm (Common for M8, especially on Japanese motorcycles)
- 13mm (Common for M8, widely used)
- 14mm (Common for M10)
- 15mm (Common for bicycle pedals/axles)
- 17mm (Common for M12, wheel lug nuts)
- 19mm (Common for M12, lug nuts)
2. Large/Heavy Duty Sizes (20mm+)
Used for larger machinery, heavy automotive, and specialized, heavy-duty applications:
- 21mm (Common for lug nuts/spark plugs)
- 22mm (Common for oxygen sensors, heavy machinery)
- 24mm (Common for large nuts, trucks)
- 27mm
- 30mm
- 32mm (Often used for machinery/heavy equipment)
3. Common Allen Key/Hex Key Sizes (1.5mm - 10mm)
Common in Chinese-manufactured kits (e.g., Qil Lang Tools) for socket-head fasteners:
- 1.5, 2, 2.5, 3, 4, 5, 6, 8, & 10mm
Common Set Configurations
- Small Sets: Often 6mm - 14mm
- Medium Sets: Typically 8mm - 19mm
- Large Sets: Include up to 24mm, 27mm, or 32mm