You can rent an auger in three forms: a handheld one or two person unit for fence posts in cooperative soil, a towable hydraulic digger for hard or stony ground, and an auger drive hung off a skid steer or mini excavator for volume work. Ground condition and hole count pick the drive, not the hole diameter.
One person, two person or machine mounted
A one person auger drills six to eight inch holes in soft soil and fights you in anything firmer. A two person unit manages up to about twelve inches. Beyond that diameter, or beyond roughly a dozen holes, take the drive on a machine: the hydraulics do the work and your shoulders do not.
What each drive costs for a day
Counter rates for a handheld unit commonly land near $60 to $110 a day, with bits charged separately by diameter. A towable hydraulic digger sits nearer $150 to $250. An auger drive taken with a skid steer is priced as an attachment on top of the machine rate, usually a modest daily addition.
The bit is chosen by the ground, not the post
Standard flighting works in loam and clay. Rocky fill, caliche and frozen ground want a rock bit or carbide tipped flighting, and a yard that stocks them will say so on the phone. Arriving with the wrong bit costs a whole day, so describe the soil when you book and ask what is available for it.
Get the utility marks down before you book the day
Every buried service is somewhere, and an auger finds them quickly. Free utility locating is available nationwide and takes a couple of working days, so schedule the hire for after the marks appear. Rental contracts put what you hit squarely on you, usually in plain words near the signature.
Questions people ask about rent an auger
Is it worth renting an auger for a single post?
Rarely. One hole in reasonable soil is faster with a shovel and a clamshell digger, which the same counter hires for a few dollars. The auger earns its rate somewhere around the fifth hole, or on the first hole if the ground is hard enough to defeat hand tools.
Does the rate include the auger bit?
Usually not. The powerhead and the flighting are separate line items, priced by diameter and sometimes by length. Confirm which diameters the yard actually has in stock when you reserve, because the common sizes go out first on a fencing weekend.
What hole size do I need for a 4x4 post?
About three times the post width if it is being set in concrete, so a nine to twelve inch bit for a 4x4. Depth is normally a third of the post length or below the local frost line, whichever is deeper, and the yard can advise what depth its flighting reaches in one pass.