A #1 screwdriver is a Phillips #1 (PH1), sized for small Phillips-head screws common in electronics and appliances.
If you grabbed a screwdriver set to fix a laptop, game console, or home theater receiver, the #1 driver is likely the one doing the work. A #1 screwdriver means a #1 Phillips tip, which fits Phillips screws gauged roughly 2 through 4. The catch: that numbering only works inside the Phillips drive family, so matching the screw head type matters just as much as the size.
What Size Is A #1 Screwdriver?
In the Phillips system, #1 is the tip size designation, often marked as PH1 or PH #1 on the handle or shaft. It sits between the smaller #0 and the larger #2, which is the most common size for household screws.
Real-world specs show the pattern clearly. Klein Tools lists its model 603-3 as a #1 Phillips with a 3-inch round shank and an overall length of 6.75 inches. Jonard’s equivalent driver uses the PH1 label and a 3-inch shaft that meets ASME B107.600 and ANSI ISO 2380 standards. Aven’s #1 driver offers a 150 mm working length. The shared label across these brands is exactly why “What is a #1 screwdriver?” has one simple answer: it’s a Phillips #1 tip.
What Are #1 Screwdrivers Used For?
Phillips #1 drivers handle small fasteners, which is why they show up in electronics and light assembly work. You will reach for one when opening a game controller, mounting a server rack, or tightening the screws that hold a wall plate onto a laptop.
That said, #1 is not a universal size. The numbering shifts entirely between drive styles:
- Phillips #1 fits Phillips recesses and matches screw gauges 2 through 4.
- Slotted #1 refers to blade width and thickness, not a Phillips-style recess.
- Pozidriv #1 (PZ1) looks similar to Phillips but has extra radial lines and demands its own driver.
This is the distinction that trips people up. A Phillips #1 driver will not properly seat in a Pozidriv screw, and slipping it into a slotted head only chews up the fastener. Always match the drive type first, then the size.
How To Avoid Stripping Screws With A #1 Driver
Stripping happens when the driver tip does not fully engage the screw recess. In practical terms, an undersized tip is the usual culprit, not a worn screw.
Follow these rules on the job:
- Match the recess. Only use PH1 on Phillips heads, never on slotted or PZ1 fasteners.
- Use the largest tip that fits. If a #1 driver wobbles in the recess, step up to #2; an undersized tip causes cam-out and damage.
- Inspect worn screws. If the screw head is already chewed up, a nominally correct tip can still slip.
The smaller the screw, the less force it tolerates. Press down firmly and turn slowly; Phillips drivers are designed to cam out under excessive torque, which protects the screw but ruins the head if you force it. When you need a full lineup of sizes for the toolbox, our roundup of the best #1 screwdriver sets covers options worth the money.
Fast Facts On The #1 Screwdriver
| Driver Spec | #1 Phillips Value | Notes |
|---|---|---|
| Tip designation | PH1 / PH #1 | Same driver, different labels |
| Screw gauge range | #2 to #4 | Small fasteners |
| Typical shank length | 3 inches | Varies by model |
| Compatible drives | Phillips only | Not for slotted or PZ1 |
| Common applications | Electronics, laptops, small appliances, server racks | Larger than #0, smaller than #2 |
When a #1 tip feels loose in the recess, stop and reassess the fastener before you round it out.
FAQs
Is a #1 screwdriver the same as a Phillips?
Not exactly. “Phillips” describes the cross-shaped drive style, while “#1” is a specific tip size within that family. A #1 screwdriver is a Phillips driver, but Phillips also makes #0, #2, and #3 sizes that fit larger or smaller screws, so the terms are not interchangeable.
What size screw does a #1 Phillips driver fit?
A #1 Phillips driver fits small screws gauged roughly #2 through #4 on standard size charts. These screws appear in laptops, controllers, and small appliance housings. For bigger screws, step up to a #2 tip, which is the most common size in general household use.
Can I use a #1 screwdriver on a Pozidriv screw?
You can force it, but you should not. Pozidriv heads look similar to Phillips but have extra radial lines, and a Phillips tip will cam out or strip the recess. Check the screw head closely; if you see secondary lines between the main cross slots, reach for a PZ1 driver instead.
References & Sources
- Klein Tools. “#1 Phillips Screwdriver, 3-Inch Round Shank.” Product specs confirming the #1 tip and 3-inch shank length.
- Jonard Tools. “Cushion Grip Screwdrivers: Phillips Screwdriver.” Lists PH1 designation and ASME/ISO standard compliance.
- Wikipedia. “List of Screw Drives.” Reference for Phillips sizing, gauge ranges, and drive-style geometry differences.
