Choosing the correct screwdriver size is essential for any repair, maintenance, or DIY project. Using the right size helps prevent stripped screw heads, improves fastening strength, and makes your work safer and more efficient.
This guide includes common screwdriver size charts, explains the different screwdriver types, and provides practical tips for selecting the correct size for any job.
Screwdriver Size Chart
Flat Head Screwdriver Sizes
| 0.8 mm | |
| 1 mm | |
| 1.2 mm | |
| 1.5 mm | |
| 1.8 mm | |
| 2 mm | |
| 3/32″ | 2.5 mm |
| 1/8″ | 3 mm |
| 3.5 mm | |
| 5/32″ | 4 mm |
| 3/16″ | |
| 4.5 mm | |
| 5 mm | |
| 7/32″ | 5.5 mm |
| 6 mm | |
| 1/4″ | 6.5 mm |
| 5/16″ | |
| 3/8″ |
Hex Key Screwdriver Sizes
| .7 mm | |
| .9 mm | |
| 3/64″ | 1.2 mm |
| 1.3 mm | |
| 1.5 mm | |
| 1/16″ | 1.6 mm |
| 5/64″ | 2 mm |
| 3/32″ | 2.4 mm |
| 2.5 mm | |
| 7/64″ | 2.8 mm |
| 3 mm | |
| 1/8″ | 3.2 mm |
| 9/64″ | 3.5 mm |
| 5/32″ | 4 mm |
| 11/64″ | 4.4 mm |
| 4.5 mm | |
| 3/16″ | 4.8 mm |
| 5 mm | |
| 13/64″ | 5.2 mm |
| 7/32″ | 5.5 mm |
| 15/64″ | 6 mm |
| 1/4″ | 6.4 mm |
| 7 mm | |
| 5/16″ | 8 mm |
| 9 mm | |
| 3/8″ | 9.5 mm |
| 10 mm | |
| 1/2″ | 12.7 mm |
Robertson Screwdriver Sizes
| Orange | #00 | 1-2 |
| Yellow | #0 | 3-4 |
| Green | #1 | 5-7 |
| Red | #2 | 8-10 |
| Black | #3 | 12, 1/4″ |
| Brown | #4 | 5/16″, 3/8″ |
Phillips Screwdriver Sizes
| #0000 | 1 mm | |
| #000 | 1.5 mm | |
| #00 | 2 mm | |
| #0 | 2.5 mm | 0-1 |
| #1 | 3 mm | 2-4 |
| #2 | 3.5 mm | 5-9 |
| #3 | 5 mm | 10-14, 16 |
| #4 | 6 mm | 18, 20, 24 |
| #5 | 8 mm | 5/8″ and 3/4″ (machine screws) |
Torx Screwdriver Sizes
| T1 | .031″ | .81 mm |
| T2 | .036″ | .93 mm |
| T3 | .046″ | 1.10 mm |
| T4 | .050″ | 1.28 mm |
| T5 | .055″ | 1.42 mm |
| T6 | .066″ | 1.70 mm |
| T7 | .078″ | 1.99 mm |
| T8 | .090″ | 2.31 mm |
| T9 | .098″ | 2.50 mm |
| T10 | .107″ | 2.74 mm |
| T15 | .128″ | 3.27 mm |
| T20 | .151″ | 3.86 mm |
| T25 | .173″ | 4.43 mm |
| T27 | .195″ | 4.99 mm |
| T30 | .216″ | 5.52 mm |
| T40 | .260″ | 6.65 mm |
| T45 | .306″ | 7.82 mm |
| T50 | .346″ | 8.83 mm |
| T55 | .440″ | 11.22 mm |
| T60 | .519″ | 13.25 mm |
| T70 | .610″ | 15.51 mm |
| T80 | .690″ | 17.54 mm |
| T90 | .784″ | 19.92 mm |
| T100 | .871″ | 22.13 mm |
Why Screwdriver Size Matters
Selecting the correct screwdriver size is about more than convenience. A properly fitted screwdriver:
- Reduces the chance of stripping screw heads
- Improves grip and control
- Allows proper torque without slipping
- Protects both the screw and surrounding materials
- Makes fastening and removal much easier
Using a screwdriver that’s too small or too large can damage screws, increase repair time, and sometimes make the fastener impossible to remove.
Types of Screwdriver Heads
Different screws require different drivers. Understanding the most common types makes choosing the correct tool much easier.
Flat Head (Slotted)
One straight slot across the screw head. Common on older furniture, electrical devices, and woodworking projects.
Phillips
Cross-shaped design that offers better grip than slotted screws. One of the most widely used screw types for household applications.
Robertson (Square)
Square recess that provides excellent grip and reduces cam-out. Popular in woodworking and construction.
Torx
Six-point star-shaped design that allows higher torque and minimizes slipping. Frequently used in automotive, electronics, and machinery.
Hex (Allen)
Hexagonal socket commonly found in furniture assembly, bicycles, machinery, and equipment.
How to Choose the Correct Screwdriver Size
The easiest way to choose the right screwdriver is to match the driver tip to the screw head.
A properly sized screwdriver should:
- Fit snugly inside the screw recess
- Have little to no side-to-side movement
- Reach full depth inside the screw head
- Stay engaged while turning
If the screwdriver rocks or slips, try the next size up or down until you find the best fit.
Screwdriver Size Chart
| Screw Type | Most Common Sizes |
|---|---|
| Phillips | #0, #1, #2, #3 |
| Flat Head | 3 mm–6.5 mm |
| Torx | T10, T15, T20, T25, T30 |
| Robertson | #1, #2, #3 |
| Hex | 2 mm–8 mm |
These sizes cover most household repairs and general DIY projects.
Choosing Between Metric and Imperial Sizes
Depending on where your tools or hardware were manufactured, screwdriver sizes may be listed in either metric (millimeters) or imperial (inches).
Generally:
- European products commonly use metric measurements.
- North American hardware may use either metric or imperial sizing.
- Precision electronics frequently use metric sizing.
Keeping a screwdriver set that includes both systems ensures you’re prepared for most repair jobs.
Specialized Screwdriver Sizes for Unique Applications
Certain tasks require specialized screwdriver sets.
Precision Screwdrivers
Designed for eyeglasses, watches, smartphones, cameras, and other electronics.
Automotive Screwdrivers
Built to withstand higher torque and commonly include Torx, Phillips, and Hex drivers.
Electrician Screwdrivers
Often feature insulated handles for working around electrical systems.
Security Screwdrivers
Designed for tamper-resistant screws commonly found on appliances, gaming consoles, and public equipment.
Common Mistakes When Choosing Screwdriver Sizes
Avoid these common errors:
- Guessing the screwdriver size
- Using worn or rounded screwdriver tips
- Applying excessive force with the wrong driver
- Mixing Phillips and Pozidriv screwdrivers
- Using one screwdriver for every screw type
Choosing the proper size saves both time and frustration.
Tips for Maintaining Screwdriver Size Accuracy
Good maintenance extends the life of your tools.
- Keep screwdriver tips clean.
- Store tools in a dry toolbox or organizer.
- Replace worn or chipped tips.
- Avoid using screwdrivers as pry bars or chisels.
- Wipe tools after use to prevent corrosion.
Well-maintained screwdrivers provide better grip and more accurate performance.
DIY Projects Requiring Various Screwdriver Sizes
For most homeowners, these sizes cover the majority of repair tasks:
- Phillips #1
- Phillips #2
- Phillips #3
- Slotted 3 mm
- Slotted 6 mm
- Torx T15
- Torx T20
- Torx T25
- Hex 3 mm
- Hex 5 mm
A quality multi-piece screwdriver set containing these sizes is suitable for most household repairs.
Conclusion
Using the correct screwdriver size makes every repair safer, faster, and more effective. Whether you’re assembling furniture, repairing electronics, maintaining a vehicle, or completing home improvement projects, matching the screwdriver to the screw head helps prevent damage while improving overall efficiency.
Keeping a complete screwdriver set and referring to a reliable screwdriver size chart ensures you’ll always have the right tool for the job.
FAQs
What is the most common Phillips screwdriver size?
Phillips #2 is the most commonly used size for household repairs, furniture assembly, and general construction.
What happens if I use the wrong screwdriver size?
Using the wrong size can strip the screw head, damage the screwdriver tip, and make the screw difficult or impossible to remove.
Are Torx and Allen screwdrivers the same?
No. Torx drivers have a six-point star-shaped tip, while Allen (Hex) drivers fit hexagonal sockets.
Which screwdriver sizes should every homeowner own?
A basic toolkit should include Phillips #1, #2, and #3, several flat-head sizes, Torx T15–T25, and a few common Hex drivers.
How do I know if my screwdriver fits correctly?
A properly fitted screwdriver fills the screw recess with minimal movement and doesn’t slip while turning.
Why do some screws require Torx instead of Phillips?
Torx screws allow greater torque with less slipping, making them ideal for automotive, machinery, and heavy-duty applications.
Can one multi-bit screwdriver replace a full screwdriver set?
A quality multi-bit screwdriver works well for many everyday tasks, but a dedicated screwdriver set often provides better comfort, durability, and access in tight spaces.
How often should I replace screwdrivers?
Replace screwdrivers when the tips become rounded, chipped, bent, or no longer grip screws securely.