Recurve Bow Weight Calculator

Determine your actual holding weight based on your specific draw length

Draw Force Curve (Estimated)

Weight at Different Draw Lengths

Draw Length (in)	Estimated Weight (lbs)	Difference from Rated

What is a Recurve Bow Weight Calculator?

A recurve bow weight calculator is a specialized archery tool designed to estimate the actual holding weight of a bow at a specific draw length. Unlike compound bows, which have a "let-off" at full draw, recurve bows increase in weight the further they are drawn. This phenomenon is known as the "draw force curve."

Most recurve limbs are rated at a standard AMO (Archery Manufacturers Organization) draw length of 28 inches. However, very few archers have a draw length of exactly 28 inches. If your draw length is shorter, you will hold less weight than the rated poundage. If your draw length is longer, you will hold more.

Using a recurve bow weight calculator is essential for:

• Arrow Selection: Correct arrow spine is determined by the actual weight on your fingers, not the number written on the limb.
• Safety: Ensuring you are not "over-bowed" (pulling too much weight), which can lead to injury.
• Performance: Understanding the efficiency and stored energy of your setup.

Recurve Bow Weight Formula and Explanation

While the most accurate way to measure draw weight is using a digital bow scale, a mathematical approximation is highly effective for planning and estimation. The standard industry rule of thumb for recurve bows is that draw weight changes by approximately 2 to 3 pounds per inch of draw length deviation from the standard 28 inches.

The Calculation Formula

The calculator uses the following linear approximation formula:

Actual Weight = Rated Weight + ((Actual Draw Length – Rated Draw Length) × Weight Factor)

Variables Table

Variable	Meaning	Unit	Typical Range
Rated Weight	The poundage marked on the bow limbs.	Lbs (#)	15 – 60 lbs
Rated Length	The industry standard length for rating.	Inches (")	Usually 28″
Actual Draw Length	The archer's personal draw length.	Inches (")	24″ – 32″
Weight Factor	How much weight is gained per inch.	Lbs/Inch	2.0 – 3.0 lbs

Practical Examples of Draw Weight Calculation

Example 1: The Long Draw Archer

Scenario: An archer buys a pair of limbs rated 35 lbs @ 28″. However, this archer is tall and has a draw length of 30.5 inches.

• Difference: 30.5″ – 28″ = +2.5 inches
• Adjustment: 2.5 inches × 2.5 lbs/inch = +6.25 lbs
• Result: The archer is actually holding 41.25 lbs on their fingers.

Implication: If they bought arrows spined for 35 lbs, those arrows would be far too weak (underspined) for the actual 41+ lbs force, causing erratic flight.

Example 2: The Youth/Short Draw Archer

Scenario: A youth archer is using a club bow rated 25 lbs @ 28″. Their draw length is only 24 inches.

• Difference: 24″ – 28″ = -4 inches
• Adjustment: -4 inches × 2 lbs/inch = -8 lbs
• Result: The archer is only holding approximately 17 lbs.

Implication: This is great for learning form, but if they intend to hunt (where legal minimums apply), they might not meet the kinetic energy requirements despite the bow saying "25 lbs".

How to Use This Recurve Bow Weight Calculator

1. Enter Rated Weight: Look at the sticker or writing on the bottom limb of your recurve bow. Enter that number (e.g., 30).
2. Verify Rated Length: Leave this at 28 inches unless your bow specifies a different standard (rare, but possible on some custom bows).
3. Input Actual Draw Length: Measure your draw length. This is typically the distance from the nock groove to the pivot point of the grip plus 1.75 inches.
4. Adjust Weight Factor (Optional): The default is 2.5 lbs/inch. High-end carbon limbs might be smoother (closer to 2 lbs/inch), while basic wood/fiberglass limbs might "stack" more (closer to 3 lbs/inch).
5. Analyze Results: Use the "Estimated Actual Draw Weight" to select your arrow spine or check legal compliance.

Key Factors That Affect Recurve Bow Weight Results

While the recurve bow weight calculator provides a solid estimate, several physical factors influence the exact weight on your fingers:

1. Limb Materials (Stacking)

"Stacking" occurs when the draw weight increases disproportionately fast at the end of the draw. High-quality carbon/foam limbs are smoother and gain weight linearly. Cheaper wood/glass limbs may gain 3+ lbs per inch past 28 inches, making the calculator underestimate the weight for long draws.

2. Riser Length

Limbs are usually rated on a 25-inch riser. If you put the same limbs on a shorter 23-inch riser, the weight will increase by approximately 2 lbs because the limbs are pre-stressed more. Conversely, a 27-inch riser will reduce the weight by roughly 2 lbs.

3. Tiller Bolts

Modern ILF (International Limb Fitting) risers have tiller bolts that allow you to increase or decrease weight by approximately 5-10%. This calculator assumes the bolts are set to the mid-range/factory standard.

4. Brace Height

A higher brace height (distance from string to grip) pre-loads the limbs slightly more, potentially increasing the starting weight and the final holding weight slightly.

5. Draw Scale Accuracy

The "Rated Weight" on limbs is not always perfect. Manufacturers have tolerances. A limb marked 30 lbs might actually be 29.5 or 30.5 lbs out of the box.

6. Limb Bolt Position

If your riser allows limb alignment and weight adjustment, cranking the limb bolts all the way in can add 2-4 lbs to the rated weight before you even account for draw length.

Frequently Asked Questions (FAQ)

Does draw weight affect arrow spine?

Yes, absolutely. Draw weight is the primary factor in choosing arrow spine (stiffness). A heavier draw weight requires a stiffer arrow (lower spine number, e.g., 400), while a lighter weight requires a more flexible arrow (higher spine number, e.g., 600).

What is the legal minimum draw weight for hunting?

This varies by jurisdiction, but commonly it is 40 lbs or 45 lbs at your actual draw length. Use this recurve bow weight calculator to ensure you meet the legal requirement at your draw length, not just what the limb says.

How do I measure my draw length accurately?

Stand with your back against a wall, arms spread wide (wingspan). Measure fingertip to fingertip in inches and divide by 2.5. This gives a very close approximation of your AMO draw length.

Why does my bow feel heavier than the calculator says?

You might be experiencing "stacking." If you have a long draw length (e.g., 30″+) and are using a short bow (e.g., 62″ AMO), the string angle becomes acute and the limbs lose mechanical advantage, causing weight to spike rapidly.

Can I reduce the weight of my recurve bow?

Only slightly. If you have an ILF riser, you can back the tiller bolts out to reduce weight by about 5-10%. Otherwise, you must purchase lighter limbs.

Does this calculator work for longbows?

Yes, the physics are similar for traditional longbows. However, longbows often stack faster than recurves, so you might want to increase the "Weight Change Factor" to 3.0 lbs/inch for better accuracy.

What is the difference between AMO and ATA standards?

For recurve draw weight, AMO (Archery Manufacturers Organization) is the standard, measuring at 28 inches from the nock groove to the pivot point + 1.75 inches (or to the front of the bow). ATA is more common in compound bows.

Is a higher draw weight always better?

No. Accuracy is far more important than power. It is better to shoot a 30 lb bow accurately than to struggle with a 50 lb bow and miss the target. Only increase weight when you can control it perfectly.

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