What Size Combination Wrench Set Do You Need?

What "size" means on a combination wrench

A combination wrench has an open end on one side and a box end on the other. Both ends are the same size, and that size is the distance across the flats of the nut or bolt head it fits. A 13 mm wrench fits a 13 mm fastener, and a 1/2 inch wrench fits a 1/2 inch fastener.

There are two measuring systems. SAE sizes are inch-based and shown as fractions, like 3/8 or 7/16. Metric sizes are shown in millimeters, like 10 or 13. They are close in places but not interchangeable. Using a nearly right wrench is the quickest way to round off a fastener.

Which size range fits your work

Many mechanics find the middle of each range does most of the work, and the extreme ends are used less often. Even so, a set that skips a size you need is frustrating, so scan the full size list before you buy.

How to read piece counts and size ranges

Notice that the two largest sets reach 32 mm, while the ratcheting sets stop at 19.05 mm. Our best combination wrench set page lays out these ranges next to steel, finish and storage so you can match them to your needs.

A simple way to choose

Work through these steps before you compare any sets:

• List the machines and projects you expect to work on, and note whether they use inch or metric fasteners.
• If you are unsure, plan on both systems. Cars and tools from different makers often mix them.
• Pick the smallest and largest sizes you realistically need, then add a little room at the top for surprises.
• Check the size list for gaps. Some sets skip common sizes, like 9 mm or 11/32 in.
• Decide on a box end style. A 12-point box end engages at more angles, and a six-point grips flats better on stubborn nuts.
• Choose storage that suits you. A roll-up pouch is compact, while a hard case protects the wrenches and shows what is missing.

Extras that change what you need

A ratcheting box end speeds up work in open areas and can help in tight ones, though it adds moving parts. The CRAFTSMAN set lists a 90-tooth mechanism and the ELEAD set lists 72 teeth with a 5° swing arc. A 15° offset lifts the handle so your knuckles clear the work.

A standard combination set cannot reach every fastener. Fittings such as brake lines and fuel lines are often better served by a different tool. If you work on those, see our best crowfoot wrench set page for a tool that suits those tight spots.

Safety notes

Wrenches look simple, but they slip, and a slip can hurt your hand or face. A few habits help:

• Wear safety glasses. Rusted fasteners can snap, and debris can fall when you work overhead.
• Pull the wrench toward you rather than pushing it, so your hand is not driven into a sharp edge if it slips.
• Make sure the wrench is fully seated on the fastener. Never use a loose or wrong-size wrench.
• Do not add a pipe to the handle for extra leverage. It can break the wrench or the fastener.
• Support a raised vehicle with jack stands, never a jack alone.
• Disconnect the battery before working near electrical connections, and never use a metal wrench on live circuits.

Frequently asked questions

Should I buy SAE, metric or a combined set?

A combined set is the safer choice if you work on a mix of machines. Choose one system only if you are sure every fastener you touch uses it, such as a compact metric-only roll for a single type of equipment.

Are 12-point or six-point box ends better?

It depends. A 12-point end engages at more angles, which helps in tight spots. A six-point end grips the flats better and suits stubborn or worn fasteners.

Do I need every size in the range?

Not always. Many people use a core of common sizes most of the time. A set with fine size steps costs you less trouble when you meet an odd size, but only buy the range your work actually needs.

What does ANSI B107.6 on a listing mean?

It is a quality standard that some makers cite for wrench sets. We report that the EFFICERE listing says its set exceeds it, but we compare published claims and have not verified them.