How to Adjust Draw Length on a Compound Bow

Knowing how to adjust draw length is one of the most useful skills a compound shooter can have. Draw length decides where your anchor lands, how your bow arm sets up and whether your peep lines up without straining. When it is right, the bow feels like it was built for you. When it is wrong, you fight it on every shot.

The good news: on most modern bows, adjusting draw length is a simple, repeatable job once you understand which cam system you have. This Better Outdoors guide is brand-neutral. It covers how to measure, how to identify rotating modules versus module swaps versus cam-specific draw lengths, a step-by-step process, how draw stops and let-off fit in, and what to re-tune afterward. If you own a PSE, our PSE draw length adjustment guide covers PSE charts and models in detail.

Try the free Draw Length CalculatorEstimate your draw length from wingspan or height.

Step Zero: Measure Before Adjusting Draw Length

Adjusting draw length without a target number turns into endless guesswork. Draw length is measured from the nocking point on the string to the pivot point of the grip, plus 1.75 inches (the ATA standard). You don’t need to measure the bow to start, though. You need to measure you.

1. Stand against a wall with your arms straight out to the sides, palms forward, without stretching.
2. Have a helper measure from middle fingertip to middle fingertip in inches.
3. Divide by 2.5. A 71-inch wingspan gives a starting point of about 28.5 inches.

That number is a baseline. Release style shifts it: shooters using a wrist-strap index release often end up a little shorter than the formula, while some handheld release shooters settle slightly longer. A draw check arrow at a pro shop gives you a second opinion, and real shooting gives you the final answer.

Signs Your Draw Length Is Right

• The string touches your nose and the corner of your mouth without you reaching for it
• Your bow arm has a slight, relaxed bend at the elbow
• Your front shoulder stays down and relaxed at full draw
• Your peep lines up with your eye at a natural head position
• You can hold steady on target for several seconds

Too long feels stretched, with string slap and a raised shoulder. Too short feels cramped, with a floating anchor.

Identify Your Cam System First

This is the step most people skip, and it decides everything else. Look closely at your cams. You’ll find a cam name or code stamped or printed on them, and usually small numbers or letters next to module holes. That cam name is what you’ll look up on the manufacturer’s chart.

Rotating Module vs. Module Swap

The rotating module vs. module swap question comes up constantly. A rotating module is a single piece bolted to the cam with several holes. You remove a screw or two, rotate it to the position your chart lists, and reinstall. Beginner, youth and many hunting bows use this wide-range, often press-free design.

A module swap uses separate mods, each sized for a specific draw length (or a small range). You buy or borrow the correct mod, remove the old one and bolt in the new one. Swappable mods are common on flagship bows because a dedicated mod can be optimized for one length. The trade-off: you need the right part, and often a press.

Cam-Specific Draw Lengths

Some bows, especially older single-cam designs and certain performance cams, have a draw length that is built into the cam itself. If there is no module, or the module only fine-tunes within a narrow window, a bigger change means ordering a new cam from a dealer. Give the dealer the bow model and serial number, because cams are model-specific.

Brand Notes: Mathews, Bear and PSE

Systems change from model to model, so treat these as orientation, not instructions:

• Mathews draw length mods: Mathews uses mods to set draw length, and depending on the model that can mean a rotating mod or a separate mod for each draw length. Because Mathews sells through dealers, your pro shop can confirm which mod your bow needs. Our guide to Mathews compound bow packages explains how that dealer setup works.
• Bear draw length adjustment: Bear bows use module systems that vary by cam. Many hunting and RTH models are designed for owner adjustment, but check the owner’s manual or Bear’s support pages for the chart that matches the cam on your bow.
• PSE draw length chart: PSE publishes a chart for each cam system. There is no single chart for every PSE bow. See our PSE-specific guide for how to read one.

How to Change Draw Length on a Compound Bow: Step by Step

Here is the general process for how to change draw length on a compound bow with a module system. Work slowly, and photograph everything before you touch it.

You’ll need the chart for your cam, a dedicated archery hex key set (to avoid stripped screws), a phone for photos, a draw weight scale and, if your system needs one, a bow press.

Step 1: Record Your Current Settings

Write down the current module position (and draw stop and string post position, if your cam has them) on every cam. Take close-up photos of both cams. If anything goes wrong, you can return to a known starting point.

Step 2: Find the Target Position on the Chart

Look up your target draw length on the chart for your cam. Note the module position or mod size, any string post setting and any draw stop position listed. Move ½ inch at a time if you’re fine-tuning; bigger jumps are fine when you know the target from a fitting.

Step 3: Check Whether the Module Is Loaded

Try loosening a module screw a quarter turn. If it turns freely and the string and cables stay seated, the module isn’t carrying load. If the screw binds or the module wants to shift under tension, stop. You need a bow press.

Step 4: Move or Swap the Module

For a rotating module, remove the screws, rotate the module so the chart’s position lines up with the mounting hole, and reinstall. For a module swap, press the bow if required, remove the old mod and install the new one in the orientation the manual shows.

Step 5: Match Every Cam

On dual-cam, hybrid and binary systems, set both cams to the same position. A mismatch throws off cam timing, which shows up as a lumpy draw cycle, a soft or uneven back wall and inconsistent arrow flight. Single-cam bows only have one module to move, but check the idler for any matching setting the manual lists.

Step 6: Tighten and Test-Draw

Tighten screws snug, not cranked; aluminum threads strip easily. Draw the bow slowly several times, listening for clicks and watching that the string and cables track cleanly.

Draw Stops, Let-Off and Draw Length

Draw stops are small pegs or adjustable posts that set where the cam stops rotating. On many cams they are tied to draw length, and on some they also set let-off. That means a draw length change can quietly change how your back wall feels.

• Draw stops tied to modules: Some modules carry the draw stop, so moving the module moves the stop. Others have a separate stop that must be moved to a matching position.
• Adjustable let-off: Cams with let-off settings often use the draw stop position to control it. Moving the stop can change both let-off and the effective draw length slightly.
• Timing the stops: On dual-stop systems, both stops should make contact at the same moment.

Change one variable at a time: set draw length first, shoot it, then adjust let-off if you need to.

After Adjusting Draw Length: Re-Tune the Bow

Adjusting draw length changes where your eye, anchor and arrow sit. Plan to re-tune these items afterward:

Your arrows may also be affected. A longer draw length stores more energy, which can call for a stiffer spine. Use our arrow speed calculator to estimate the speed change at your new setting.

Do You Need a Bow Press for Draw Length?

It depends on your cam. Many rotating-module bows are designed for press-free changes because the module isn’t carrying load. Swappable mods, string post changes and new cams usually need a press. A quick rule: if your manual says press-free, and the screw turns freely, you’re fine. If not, press it.

A portable bow press is worth owning if you work on your own bows often. If you only adjust once, a pro shop will usually do it quickly.

When to Use a Pro Shop

At Better Outdoors we recommend a pro shop when:

• Your bow needs a press you don’t have, or a new mod or cam
• You can’t find the chart for your cam
• Cam timing or draw stops look uneven after the change
• The draw cycle feels rough, noisy or inconsistent
• You want your draw length verified on a draw board with a coach watching your form

Common Mistakes When You Adjust Draw Length

• Adjusting only one cam on a dual or hybrid system
• Forgetting the draw stops, leaving a soft or uneven wall
• Judging by feel in the living room instead of shooting groups
• Leaving the peep where it was and craning your neck to find it
• Guessing module positions instead of using the chart

Shoot at least 30 arrows at a new setting and compare 20-yard groups before you decide.

Final Thoughts on How to Adjust Draw Length

Learning how to adjust draw length comes down to three habits: measure honestly, follow the chart for your exact cam, and re-tune everything the change touches. Do that, and a quick module move turns into better posture, a steadier hold and tighter groups.

Frequently Asked Questions