Walk onto any site and you will see both on the floor: a combi drill and an impact driver, usually from the same battery platform. They look similar, both make holes in things and drive screws, and the price difference is small. So which one do you actually need, and is it worth carrying both?
What a Combi Drill Actually Does
A combi drill is the all rounder. It drills into wood, metal and, with hammer action engaged, masonry. It has a keyless chuck that takes round and hex shank bits, an adjustable clutch so you can drive screws without stripping heads, and two gear ranges: low for torque, high for speed.
The clutch is the underrated part. Set it correctly and you can drive hundreds of screws into softwood or plasterboard without burying a single head. For carcassing, stud work, kitchen fitting and general first and second fix, a decent combi covers most of the day.
What an Impact Driver Does Differently
An impact driver only drives fasteners, but it does it in a completely different way. Alongside rotation, an internal hammer and anvil deliver rapid rotational blows, typically over 3,000 impacts per minute. Each blow adds a burst of torque without twisting your wrist.
In practice that means three things on site:
- Long screws stop being hard work. 100mm+ timber screws, coach screws and TimberLOK type fixings go in without pilot holes in most softwood.
- No wrist snap. The blows happen inside the tool, so when a screw bites hard the tool does not wrench your arm the way a high torque drill can.
- Less cam out. The impact action keeps the bit seated, so you strip fewer heads, especially with Torx and Pozi screws.
The trade offs: impact drivers are loud, they only take 1/4 inch hex bits, there is no clutch, and the torque is too brutal for small or delicate fixings unless the driver has electronic speed modes.
Where Each Tool Wins
Reach for the combi when you are:
- Drilling holes of any kind, in any material
- Driving small screws, hinges, sockets and anything with a torque limit
- Working on finish sensitive jobs where a clutch protects the workpiece
- Doing occasional light masonry drilling with hammer action
Reach for the impact driver when you are:
- Driving long or large diameter screws all day, decking being the classic example
- Fixing joist hangers, coach screws and structural fixings
- Running self drilling tek screws into metal
- Doing repetitive second fix screwing where speed matters more than finesse
Do You Need Both?
If you drive screws for a living, yes, and most trades end up there. The pairing is the point: hole in one hand, fastener in the other, no bit swapping in and out of a single chuck all day. Bare tool prices make the second body cheap if you stay on one battery platform, which is also why our guide to the best cordless combi drills in the UK leans heavily on platform choice rather than individual specs.
If you only buy one:
- Buy the combi if your work is varied. It does 90 percent of what the impact driver does, just slower and with more wrist strain on big fixings.
- Buy the impact driver only if your day is almost entirely driving fasteners and you already have some way to drill holes.
For a current shortlist of impact drivers worth the money, see the independent round up of the best cordless impact drivers in the UK.
What About Torque Figures?
Manufacturers shout about newton metres, but the numbers are measured differently between drills and impact drivers, so do not compare them directly. A 60Nm combi is a strong drill; a 180Nm impact driver is mid range. What matters more in use is battery platform, brushless motors for runtime and lifespan, and electronic modes that tame the power for delicate work.
The Bottom Line
The combi drill is the tool you cannot do without. The impact driver is the tool that makes half your combi work faster and kinder on your body. Most tradespeople who try the two tool setup never go back to one, and because both usually come as twin kits on one platform, the second body costs less than a day rate.
Whichever way you go, price the kit into your work properly. If you are still writing quotes by hand at 9pm, that is the bigger time drain, and it is the one QuoteSmith fixes.