Quick verdict
A moulded post level that wraps around a corner of a post with three vials, reading plumb in both directions at once, and holds itself on with a magnetic strip on metal or a rubber strap on wood. Both hands are then free to brace or backfill. It fits 4x4 and 6x6 posts, pipe and railing uprights. It is the simplest tool in deck and fence building and one of the few that is used on every post.
Strengths
- Three vials read plumb both ways and level on top
- Magnetic strip holds on metal posts and pipe
- Rubber strap holds on wood posts
- Hands-free so you can brace and backfill alone
- Durable moulded frame from a long-established brand
Weaknesses
- Vials are small; read them close
- Strap perishes after years in sun
- No use on round posts smaller than the frame
The overall YardToolLab Score is out of 100. Section scores are out of 10.
Two Bubbles, No Hands
Setting a post alone means holding it plumb, holding a level against it and shovelling concrete, which is one hand short. A post level fixes that. IRWIN’s wraps around the corner of a post with three vials, two reading plumb in each direction and one reading level across the top, and holds itself on with a magnetic strip on steel or a rubber strap on wood. Both hands are free.
This review is based on the maker’s specifications and on how post levels are used in fence and deck building generally. We have not used this level ourselves.
How It Works
Strap or stick it to the post near the top, then move the post until both side bubbles centre. Brace it, check again, pour. Because it reads both directions at once, a post cannot be plumb one way and leaning the other, which is the common failure with a single spirit level. The top vial levels post caps and railings.
Attachment
On steel fence posts, pipe and metal railing uprights the magnet holds firmly. On 4×4 and 6×6 wood posts the rubber strap stretches around and holds without marking. Either way the level stays put while you shovel, which is the whole point.
Accuracy and Build
Fence and deck work needs a post within a sixteenth over its height, and the vials deliver that when read close. The moulded frame survives being dropped in gravel and left in the truck. The strap is the one perishable part; after years of sun it stretches, and a replacement band or a bungee serves.
Where It Is Used
Fence posts, deck posts, railing balusters, mailbox and sign posts, pergola uprights, pipe and conduit. Anywhere something must stand straight and you are working alone.
Who Should Buy It
- Anyone setting fence or deck posts.
- Solo builders who need both hands.
- Homeowners with a mailbox or sign post that leans.
Common Owner Complaints
Small vials and a strap that eventually loses its stretch. Read it close; replace the band.
Technique Tips
Fit the level near the top of the post where a small lean shows as a big bubble movement, and sight the post against a far reference as a second check. When bracing, set the first brace, re-read the level, then set the second; the first brace often pulls the post slightly. Leave the level on while the concrete or gravel goes in and give it a last look before walking away.
Care
Keep the vials out of direct sun in storage so they do not yellow, and wipe concrete splatter off the frame before it sets on the magnet. A level that lives in the truck door pocket is ready for every post.
Alternatives to Consider
The Johnson post level is the near-identical rival. Firecore sells a two-pack with reflective backing. A 4 foot level and a helper is the traditional method.
Verdict
A post level costs little and is used on every post you ever set. IRWIN’s version holds itself on, reads both directions and lasts; strap it on and your fence will be the straight one on the street.
Full specifications
IRWIN Tools 1794482 Magnetic Post Level with Rubber Strap FAQs
The L-shaped frame sits on two adjacent faces of the post. One vial reads plumb in each direction and the top vial reads level. Adjust the post until both side bubbles centre.
A spirit level checks one face at a time and needs a hand to hold it. A post level reads both at once and holds itself, which is what a single person setting posts needs.
Yes. The rubber strap stretches around 6x6 posts and the magnet handles steel posts of any size.
Accurate enough for fence and deck posts, where a sixteenth over 4 feet is invisible. It is not a machinist tool.
