How to Calculate Your Draw Weight

Professional Archery Calculator & Guide

Draw Weight vs. Draw Length Curve

This chart simulates the force curve of your bow compared to your recommended range.

Draw Weight Reference Table

Archer Category	Typical Body Weight	Suggested Draw Weight
Small Child	70-100 lbs	10-15 lbs
Small Woman / Youth	100-130 lbs	25-35 lbs
Medium Woman / Small Man	130-150 lbs	30-40 lbs
Large Man	180+ lbs	55-65+ lbs

Understanding how to calculate your draw weight is the single most important step for any archer, whether you are a beginner picking up your first recurve or an experienced hunter tuning a compound bow. The correct draw weight ensures accuracy, prevents injury, and maximizes the efficiency of your equipment.

This guide will walk you through the definitions, the mathematical formulas used to estimate draw weight based on body type, and the physics of how draw weight changes with draw length.

What is Draw Weight?

Draw weight is defined as the amount of force (measured in pounds, lbs) required to pull a bowstring to a specific distance. Unlike a firearm where the energy is stored in the powder, in archery, the energy is stored in the limbs of the bow by the archer's muscles.

There are two distinct ways to look at draw weight:

• Rated Draw Weight: The weight measured at a standard draw length (industry standard is 28 inches for recurve and longbows).
• Actual Draw Weight (On The Fingers): The actual weight you hold at your specific draw length. If your arms are longer than 28 inches, you are holding more weight than the bow is rated for.

Common misconceptions include the idea that a higher draw weight always equals better performance. While higher weight adds speed and kinetic energy, it degrades accuracy if the archer cannot control it comfortably.

Draw Weight Formula and Mathematical Explanation

While there isn't a single universal formula for "ideal" weight (as it depends on muscle density), there is a precise formula for calculating your Draw Length, which directly influences your actual draw weight.

1. The Draw Length Formula

Before determining weight, you must know your length. The standard method is the "Arm Span" method:

Draw Length = Arm Span (inches) ÷ 2.5

2. The Adjusted Draw Weight Formula

If you have a bow rated for a specific weight at 28 inches, you can calculate the approximate weight at your specific draw length using this linear approximation (valid for most recurve bows):

Actual Weight ≈ Rated Weight + (Your Draw Length – 28) × 2.5

Note: The factor of 2.5 lbs per inch is a standard heuristic for recurve bows. Compound bows behave differently due to cams and let-off.

Variables Table

Variable	Meaning	Unit	Typical Range
Arm Span	Distance fingertip to fingertip	Inches	60″ – 80″
Rated Weight	Bow force at 28″ draw	Lbs (#)	15# – 70#
Stacking Factor	Weight gain per inch past 28″	Lbs/Inch	2 – 3 lbs

Practical Examples (Real-World Use Cases)

Example 1: The Tall Beginner

Scenario: John is 6'2″ with a 75-inch arm span. He buys a 30# recurve bow rated at 28″. He wants to know what he is actually pulling.

• Step 1: Calculate Draw Length. 75 ÷ 2.5 = 30 inches.
• Step 2: Calculate Difference. 30″ – 28″ = +2 inches over standard.
• Step 3: Calculate Added Weight. 2 inches × 2.5 lbs/inch = +5 lbs.
• Result: John is actually holding 35 lbs, not 30 lbs. This might be too heavy for a beginner, affecting his form.

Example 2: The Youth Archer

Scenario: Sarah has a 60-inch arm span. She is using a club bow rated 25# at 28″.

• Step 1: Calculate Draw Length. 60 ÷ 2.5 = 24 inches.
• Step 2: Calculate Difference. 24″ – 28″ = -4 inches under standard.
• Step 3: Calculate Reduced Weight. -4 inches × 2.5 lbs/inch = -10 lbs.
• Result: Sarah is only holding approximately 15 lbs. This is good for learning, but she may not get the arrow speeds expected from a "25 lb" bow.

How to Use This Draw Weight Calculator

1. Select Gender/Build: This sets the baseline muscle mass assumption for the recommendation engine.
2. Enter Body Weight: Heavier individuals generally possess more core strength, allowing for a higher starting draw weight.
3. Enter Arm Span: Measure this accurately against a wall. This calculates your draw length.
4. Select Experience: Beginners are penalized in the calculation to ensure they start light and learn proper form.
5. (Optional) Enter Bow Rating: If you have a bow, enter its poundage to see the "On The Fingers" calculation in the chart.

Key Factors That Affect Draw Weight Results

When learning how to calculate your draw weight, consider these six critical factors:

• 1. Physical Conditioning: Archery uses specific back muscles (rhomboids and levator scapulae) that are rarely used in daily life. General gym strength does not always translate to archery strength.
• 2. Bow Type (Let-off): Compound bows have "let-off," meaning you might pull 70 lbs peak weight but only hold 14 lbs at full draw. Recurve archers hold the full weight.
• 3. Limb Materials: Carbon and foam limbs may have a smoother draw curve (less weight gain per inch) compared to wood/glass limbs, affecting the "stacking" calculation.
• 4. Purpose (Target vs. Hunting): Target archers shoot 100+ arrows a day and need lower weight for endurance. Hunters shoot once and need higher weight for kinetic energy.
• 5. Draw Length: As shown in the formula, a longer draw length mechanically increases the weight of the bow.
• 6. Age and Growth: For youth archers, draw weight capabilities can change every few months. It is vital to re-calculate frequently to avoid injury.

Frequently Asked Questions (FAQ)

Q: Can I start with a heavy draw weight to build muscle?

A: No. Starting too heavy (overbowing) leads to poor form, "target panic," and shoulder injuries (rotator cuff tears). It is cheaper to buy lighter limbs now than pay for physical therapy later.

Q: How do I measure my arm span alone?

A: It is difficult to do alone. Stand against a wall, mark one fingertip, and have a friend mark the other. If alone, hold a tape measure in one hand and stretch, but this is less accurate.

Q: Does draw weight affect arrow spine?

A: Yes, absolutely. Higher draw weight requires a stiffer arrow (lower spine number). If you increase your draw weight, you must re-tune your arrows.

Q: What is "stacking"?

A: Stacking occurs when the bow is drawn past its optimal design limit, causing the weight to increase exponentially rather than linearly. This makes the bow feel very harsh at full draw.

Q: Is the 2.5 lbs per inch rule exact?

A: It is an approximation. Short limbs stack faster (3+ lbs/inch) while long limbs stack slower (2 lbs/inch). It is accurate enough for estimation.

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