Quick answer: A bow square (also called a T-square) is a small L- or T-shaped tool that clips onto your bowstring to measure two key things accurately: your brace height (string-to-grip distance) and your nocking point location. It is cheap, simple, and essential for tuning a bow correctly — getting these measurements right is the foundation of consistent, accurate shooting.
Tuning your bow and keep hearing that you need a bow square? This little tool is one of the most useful and affordable gadgets in archery — and one of the most overlooked by beginners. It looks like a small ruler with a clip, but it solves two problems that quietly wreck accuracy: setting your brace height and placing your nocking point in exactly the right spot. Get those wrong, and no amount of practice will fix your flyers.
Here is why it matters: a bow square clips onto your string and lets you measure precisely, instead of guessing. Where is the right spot to tie your nock? How far should the string sit from the grip? A bow square answers both with a quick, repeatable measurement. It is the kind of tool that pays for itself the first time you tune a bow.
In this guide, you will learn exactly what a bow square is, how to use it for brace height and nocking point, and why it matters. We will compare types in clear tables, walk through using one step by step, and share pro tips and common mistakes. By the end, you will tune with confidence. Let us measure up.
📚 What You Will Learn
What Is a Bow Square?
A bow square, often called a T-square, is a small measuring tool shaped like a T or L. One arm clips onto your bowstring, and the other arm extends out with a ruler scale. This lets you take accurate measurements from the string — most importantly your brace height and the exact position of your nocking point.
It matters because bow tuning depends on precise, repeatable measurements. Eyeballing your brace height or guessing where to tie your nock leads to inconsistent arrow flight. A bow square removes the guesswork, giving you the same accurate reference every time you set up or check your bow.
These tools are inexpensive and last for years. To compare options, you can see bow square options on Amazon. Want to understand the measurements first? See our brace height guide and arrow nocks guide.
“A bow square is the cheapest precision in archery. For the price of a couple of arrows, you get exact, repeatable tuning measurements — the foundation every accurate shot is built on.”
Why You Need One in 2026
As more archers learn to tune their own bows at home, the humble bow square has become a must-have first tool. It is cheap, simple, and unlocks two of the most important tuning measurements — which directly affect accuracy. There is no reason to skip it.
Here is why it stays essential:
- Accurate brace height. Setting and checking brace height keeps your bow in tune and shooting consistently.
- Correct nocking point. A precisely placed nock is critical for clean arrow flight — a bow square nails it.
- DIY tuning. Home tuners save shop trips by measuring accurately themselves.
- Repeatability. You can restore the exact same setup after a string change or new bow.
In short, a bow square is the small tool that makes all your other tuning possible. It belongs in every archer’s kit, beginner to expert.
Measuring Brace Height
Brace height is the distance from the deepest part of your grip (the throat) to the bowstring at rest. It affects your bow’s speed, forgiveness, and noise, and every bow has a recommended range. A bow square lets you measure it precisely so you can set the string to the right spot.
To measure: clip the bow square onto the string and let the ruler arm rest against the grip. Read where the throat of the grip lines up on the scale — that is your brace height. If it is outside the manufacturer’s recommended range, you adjust it (by twisting the string on a recurve, or having a shop adjust a compound).
Getting brace height right is one of the most important tuning steps. Too low or too high and your bow can be loud, harsh, or inconsistent. For the full explanation, see our brace height guide.
Setting Your Nocking Point
The nocking point is the spot on the string where you nock (clip) your arrow. It must be at the correct height so the arrow sits level (or very slightly nock-high) relative to the rest. If it is off, the arrow leaves the bow at a slight up or down angle, causing poor flight and vertical tuning issues.
A bow square is the perfect tool to set it. Clip the square on, rest the ruler arm on the arrow rest, and the scale shows you exactly where the string crosses at a 90-degree (square) reference. You then mark and tie your nocking point a small, precise distance above that square point — the exact amount depends on your setup.
This precision is why a bow square is essential: a nocking point set by eye is rarely right, but one set with a square is repeatable and correct. Learn more in our arrow nocks guide.
Types of Bow Squares
Bow squares are simple, but there are a few variations:
- T-square (clip-on): The classic. A T-shaped tool that clips on the string with a ruler arm. Cheap, light, and does brace height and nocking point. The go-to for most archers.
- L-square: An L-shaped version that does the same jobs; some prefer the shape.
- Combination/serving squares: Some have extra scales or features for serving and tiller measurements.
Recommendation: For nearly everyone, a basic clip-on T-square is all you need. It is inexpensive, accurate, and covers brace height and nocking point — the two measurements that matter most. Spend your money on arrows, not a fancy square.
What a Bow Square Measures
| Measurement | What It Is | Why It Matters |
|---|---|---|
| Brace height | String-to-grip distance | Speed, forgiveness, noise, tune |
| Nocking point | Arrow position on string | Clean vertical arrow flight |
| Square reference | 90° from the rest | Accurate nock placement |
| Tiller (some) | Limb balance check | Recurve tuning |
Bow Square vs Other Tuning Tools
| Tool | Main Job | Need It? |
|---|---|---|
| Bow square (T-square) | Brace height + nocking point | Yes (essential) |
| Bow press | Compress limbs for service | Pro shop / advanced |
| Arrow rest/level | Center shot, leveling | Helpful |
| Allen wrench set | Adjust accessories | Yes |
Building a tuning kit? Take our gear finder quiz for matched gear.
Step-by-Step: How to Use It
- Clip the square onto the string just above the arrow rest area.
- For brace height: rest the ruler arm against the grip throat and read the string distance on the scale.
- Compare to your bow’s spec and adjust if needed (twist the string on a recurve; shop for a compound).
- For the nocking point: rest the ruler arm on the rest and find the square (90°) point on the string.
- Mark and tie your nock the recommended small distance above square.
- Re-check after shooting and fine-tune with a paper or bare-shaft test.
Common Mistakes (and Fixes)
- Mistake: Eyeballing the nocking point. Poor arrow flight. Fix: Set it with a bow square every time.
- Mistake: Ignoring brace height. Loud, harsh, inconsistent bow. Fix: Measure and set it to spec.
- Mistake: Not re-checking after a restring. Fix: Re-measure brace height and nock after any string work.
- Mistake: Clipping the square crooked. Bad reading. Fix: Seat it square and steady before reading.
- Mistake: Skipping the tune test. Fix: Confirm with paper/bare-shaft after setting measurements.
Pro Tips
- Record your numbers — ideal brace height and nock position — so you can restore them instantly.
- Re-check after every string change, since strings stretch and settle.
- Use it to diagnose vertical flight problems (porpoising) by verifying nock height.
- Keep it in your kit alongside Allen wrenches and string wax.
- Confirm with a tune test — the square gets you close, the test confirms.
“Measure twice, shoot once. A bow square turns ‘I think that looks right’ into ‘I know that is right’ — and that certainty is what makes tuning repeatable.”
Real-Life Examples
The porpoising fix. Jordan’s arrows wobbled up and down in flight. He clipped on a bow square, found his nocking point was set too low, raised it to the correct height, and his arrows flew clean.
The restring restore. Maria got a new string and her bow felt off. She used her bow square to reset brace height to her recorded number and re-tie the nock — instantly bringing her bow back to its known tune.
The new tuner. Sam wanted to stop paying for shop tuning. A cheap bow square let him set his brace height and nocking point accurately at home, the foundation for learning to tune the rest himself.
Frequently Asked Questions
What is a bow square used for?
A bow square (T-square) clips onto your bowstring to accurately measure brace height (the string-to-grip distance) and to set your nocking point in the correct spot. These two measurements are essential for tuning a bow and getting clean, consistent arrow flight.
Do I really need a bow square?
Yes, if you want to tune or maintain your own bow. It is cheap and makes setting brace height and the nocking point accurate and repeatable. Eyeballing those measurements leads to poor arrow flight, so a bow square is one of the most worthwhile basic tools an archer can own.
How do I set my nocking point with a bow square?
Clip the square on the string and rest its ruler arm on the arrow rest to find the 90-degree (square) point. Then mark and tie your nocking point a small recommended distance above square so the arrow sits level or slightly nock-high. Confirm with a paper or bare-shaft test.
What is the difference between a bow square and a T-square?
They are the same thing — “T-square” describes the common T shape of a bow square. Some are L-shaped instead, but they all do the same jobs: measuring brace height and setting the nocking point. The name simply refers to the tool’s shape.
Can a bow square measure brace height?
Yes. Clip it onto the string, rest the ruler arm against the deepest part of the grip, and read where the string falls on the scale — that is your brace height. Compare it to your bow’s recommended range and adjust if needed for the best tune.
How much does a bow square cost?
Very little — bow squares are among the cheapest archery tools, typically costing about the same as a couple of arrows. Given how essential they are for accurate brace height and nocking-point setup, they are one of the best-value purchases in archery.
Final Verdict + Checklist
A bow square (T-square) is a small, cheap tool that delivers big accuracy by letting you set brace height and your nocking point precisely. It is the foundation of bow tuning and belongs in every archer’s kit. Measure accurately, record your numbers, and confirm with a tune test — and your bow will shoot consistently.
Your quick checklist:
- ✅ A bow square measures brace height and nocking point.
- ✅ A basic clip-on T-square is all most archers need.
- ✅ Set the nocking point with the square — never by eye.
- ✅ Set brace height to your bow’s spec.
- ✅ Record your numbers to restore them after a restring.
- ✅ Re-check after any string change.
- ✅ Confirm with a paper or bare-shaft test.
Ready to tune like a pro? Pair this with our brace height guide and how to take care of your bow guide.