One of the big questions in DIY is choosing between nails and screws, and making sure you’re picking the right one for your project—it can be the difference between success and failure. Today, we’re going to talk about the pros and cons of nails and screws, tips for choosing the right length and thickness, and advice for working with your material and environment. 

When I started out DIYing, one of my biggest concerns was in picking the right nail or screw for the project. How did I know that it was going to hold? How did I know if it was long enough or thick enough? I was stuck always having to ask for advice on every project, and I wanted to be able to know for myself. While some of this is acquired knowledge and experience that takes time, there were a few helpful tips I got along the way and some perspective I’ve gained since then that will hopefully help you on your DIY journey.

First off, a good rule of thumb for picking screws or nails for your project is this: The length should be twice the thickness of the wood you’re driving through. So if you’re driving through a one-by-four board, which is ¾” thick, then you should opt for a 1 ½” long screw or nail. There are exceptions to this rule—like if you’re driving a screw through two one-by-four boards, chances are 1 ½” screws are just going to be a hair too long, so you’ll want to opt for 1 ¼” screws instead. 

I always like to test out the length of my screws against the thickness of the wood because wood varies. Sometimes I can get away with a longer screw, and sometimes I can’t. Always consider the thickness of any hardware you’ll be going through at this point, too. It can make a big difference.

The pros and cons of nails and screws

Why should you choose a nail over a screw or vice versa? We’re going to give you some of the pros and cons of nails and screws so you can decide for yourself: Nails are thinner and are less likely to cause splitting. They can also be less noticeable than even a very small screw, and they’re easier to cover up with wood putty. Screws make it easier to be precise with lining up materials, although you can get around this by pre-drilling for your nails. Nails are less expensive, while screws are becoming more diverse and accessible. Nails are easier to pull apart with a crow-bar (unless, of course, you’re using glue). Screws, however, allow you to take apart your project and reassemble it without wrecking it. 

Hammering in nails can mar your project, especially if you’re not experienced with a hammer. And hammering is also difficult when the mass of the project is too small. The hammer tends to bounce off the wood and you risk damaging the project (or yourself). Nails hold up well under force perpendicular to the nail (but not with force parallel to the nail), whereas screws hold up well under both.

How to choose a fastener that’s best for your material and environment 

As well as choosing between nails and screws, it’s also important to make sure that you’re making a decision that’s best for your material and environment. For example, don’t choose a thick screw for thin material—you’re just asking for the wood to split. 

Just like nails, screws come in different thicknesses as well as lengths. A common screw thickness is a #8 and they work well for most projects. A larger number, like #10 will be a thicker screw that might be used to fasten thick or heavy material like timbers or hardware. A smaller number, like #6, has a thinner shank that’s better for thin or delicate materials.

Choose a wood screw for wood projects over other screws, like machine screws or sheet metal screws—the threads are designed for wood, and you won't spend extra for a specialty screw. Galvanized nails or screws react with the tannins in cedar and create black bleeding. This doesn’t compromise the integrity of the project, but it’s not always the look you want and can be avoided by using stainless steel nails or screws. 

Always choose an exterior grade screw for outdoor usage and choose an interior grade screw to save money on indoor projects. If you’re driving screws with a hammer drill, make sure you’re using structural-grade screws that can handle the downward force of the drill.

If you’re unsure of what’s the best nail or screw for your project, it never hurts to ask! We're always here to answer your questions and share our trusted advice—check out our locations and drop by.

Hopefully, though, this blog gives you a better idea of what you’re dealing with and helps empower you to start figuring out the answers to your own questions. And remember, sometimes trial and error is the best way to learn!

For more tool how-tos, check out how to use a speed square and how to use a tape measure.