






📐 Elevate your craft with the Big 12 — precision that professionals swear by!
The Swanson Tool Co S0107 Big 12 is a 12-inch speed square that combines seven essential carpentry tools into one rugged, heavy-gauge aluminum alloy device. Featuring a patented layout bar, glare-resistant matte finish, and clear black gradations, it ensures precise measurements for framing, stairway building, and roofing. Included is the Swanson Blue Book, a comprehensive 62-page guide for expert layout instructions, making this tool a must-have for pros and serious DIYers alike.







| Best Sellers Rank | #1,669 in Tools & Home Improvement ( See Top 100 in Tools & Home Improvement ) #1 in Carpentry Squares |
| Brand | Swanson Tool Co., Inc |
| Color | Silver |
| Customer Reviews | 4.8 out of 5 stars 23,144 Reviews |
| Graduation Range | 1/4 Inches |
| Material | Aluminum |
| Product Dimensions | 12"L x 1"W |
| Style | 12" Speed Square |
K**.
The ultimate pocket-sized layout tool
I've owned several speed squares over the years (cheap knockoffs, bigger 12" versions, even some plastic ones), but the Swanson Tool Co. S0101 7 Inch Speed Square (Blue) is still the gold standard — it's the one I reach for almost every single time I need accurate, quick measurements on the jobsite or in my garage. After years of daily use, it's become one of those tools that feels indispensable. Build quality — built like a tank. Made of heavy-gauge aerospace aluminum alloy with a durable blue matte finish. It's tough — won't bend, warp, or rust even after getting banged around in a toolbox, dropped on concrete, or left outside in light weather. The black-filled gradations are sharp and easy to read against the blue background, no fading or wearing off. The edges are crisp for clean scribing, and the lip (heel) is perfectly square for reliable 90° marks. Features & versatility — does way more than a basic square. 7-inch size — compact enough to fit in a pocket or tool pouch, but large enough for most framing, roofing, and layout tasks. Built-in features of a framing square, tri-square, miter square, and protractor. Graduations for common, hip, valley, and jack rafters — perfect for roof pitches and angle cuts. Scribe notches for easy pencil marking. Degree scale for quick angle measurements. Comes with the famous pocket-sized Swanson Blue Book — a mini guide packed with rafter tables, conversion charts, and how-to info for roof framing. Super handy reference right on the tool. What I use it for Marking 90° cuts on lumber Checking square on frames, cabinets, decks Laying out stair stringers and roof rafters Finding angles for trim, brackets, or miter cuts Quick squaring of sheet goods or drywall As a saw guide for circular saws (the lip hooks over the board edge perfectly) Even basic measuring and scribing in tight spaces It's incredibly accurate out of the box — no need to calibrate or second-guess it. The combo of size, durability, and all-in-one functionality makes it perfect for carpenters, woodworkers, DIY homeowners, roofers, remodelers — anyone who builds or fixes things. Value is unbeatable. Usually around $10–15 (often on sale), and it lasts forever. With over 16,000+ reviews averaging around 4.8 stars, it's consistently one of the highest-rated and best-selling carpentry squares on Amazon for good reason. No gimmicks, no plastic parts that break — just a reliable, professional-grade tool at a homeowner price. If you're starting a tool collection, upgrading from a basic combo square, or just want the classic speed square that pros swear by, this Swanson S0101 is the one. It's earned a permanent spot in every tool belt I've owned. Zero complaints — highly recommend! 5 stars all day.
M**A
Makes My Measurements Look Professional
Solid, accurate, and does not bend or feel flimsy. This speed square made my DIY projects look way more legit than my skill level probably deserves. Easy to read markings and comfortable to use — no guessing, no eyeballing, no regret.
D**D
Full function speed square
Exactly like it’s big brother but small enough to fit in an apron. I checked it for square and 45 degrees and it right on the money. Weighs practically nothing because of its aluminum construction and clear markings. Excellent value and perfectly square. I can stop looking for squares now since I have four different sizes up to 18”.
M**Z
Swanson Speed Square
The Swanson speed square is an amazing tool, and a must have in your tool inventory. I use it for all of my DIY projects, that involves carpentry. The tool is of excellent quality that's built to last. Highly recommended!!!Two thumbs up. 👍 👍
A**Y
First Timer w/Rafters and "Birdsmouth."
I'm always trying to increase my knowledge of building and carpentry and recently decided to incorporate a rafter (with bird'smouth) design into my window awning project. The Swanson square was perfect for the job and with the book it came with I was able to learn the "One-Number" rule that makes it real simple to build your roof rafters. I'd advise all first timers to do it on a smaller project--such as dog house or small shed--before a home's roof. I'm not a natural numbers guy so only read the book in a few parts, watched a quick video on the Swanson square and then went to work. I went through three sets of 2x4 rafters templates until I got the angle just right for the rafter to sit up against the ledger against the wall and the birdsmouth to land on the lower 'sill plate' that would support the window awning. I think my "ONE" number for pitch was 9 (I was using degrees{36}) and from that number you can essentially build a real roof. It came out great and from this one project I''m pretty sure I can build a real roof for any structure I design at this point. If you know your 'one' number prior to building a new project but we didn't because of other concerns such as making the awning tall enough for my clients to walk under while slope had to be steep enough to provide sufficient shade to window. As a result, my assistant and I had to test angle cuts (and then hold them up against the framing structure) until we got the approximation of 36 degree-which makes all the rafters plumb cuts. Then using the square we got the pitch of 9. More importantly, you can use a simple formula to find the distance for your birdsmouth (where your 'seat' and 'heel' cuts meet the outer edge of your bulding/sill plate). Prior to this project I only used my squares for 90degree cuts. Now, it's opened up a whole world of building possibilities. Thanks for the book, Swanson.
C**S
Heavy duty
Great sturdy quality. Clear markings
I**O
Good balance of price and functionality
It's that need for me. This tool is absolutely worth the money. The build quality feels solid, and it’s very easy to handle even for longer projects. It has become indispensable for working with wood, but it’s also versatile enough for other tasks around the workshop. A great balance of price, functionality, and durability — I’m very satisfied with this purchase. Fit me, light.
A**L
Trusted name in speed squares!
Great product! Very glad to have bought one to keep in my tool bag for tight corners and smaller trim work.
Trustpilot
2 weeks ago
1 month ago