Archery Arrow Drop Calculator

Introduction: Why Arrow Drop Matters

Arrow drop is the vertical distance your arrow falls below its original line of travel as it flies toward the target. Even a fast arrow begins dropping the instant it leaves the string because gravity is always acting on it. Understanding this drop is crucial for setting your sight, choosing pin gaps, and predicting your point of impact at different distances.

This archery arrow drop calculator is designed for bowhunters and target archers who want a quick physics-based estimate of how far an arrow will fall over a given distance. By combining your arrow’s launch speed with the shot distance, the tool predicts the drop assuming a simple, idealized trajectory. The result gives you a starting point for sight adjustments, sight tape planning, and holdover decisions.

How This Arrow Drop Calculator Works

The calculator models your arrow as a projectile launched horizontally over flat ground. It uses a standard constant value for gravity and ignores air resistance and wind. Within these limits, the underlying physics is straightforward and transparent.

The vertical drop y is computed from the basic equation of motion for constant acceleration:

where:

• y is the vertical drop (in meters).
• g is the acceleration due to gravity (approximately 9.81 m/s²).
• t is the time of flight (in seconds).

The time of flight is based on how long it takes the arrow to cover the horizontal distance at its initial speed. If v₀ is the launch speed (m/s) and x is the distance to the target (m), then:

Substituting this expression for t back into the drop formula gives:

In plain language, the drop grows with the square of distance, and it shrinks quickly as arrow speed increases. Doubling the distance increases the drop by a factor of four, while doubling the speed reduces the drop by a factor of four. This relationship explains why sight marks spread out more at longer distances and why faster setups have tighter pin gaps.

How to Use the Calculator

To get a useful prediction from the calculator, you only need two pieces of information:

1. Arrow speed (m/s) – the launch velocity of your arrow, usually measured with a chronograph.
2. Distance (m) – how far the target is from your shooting position.

Typical values for many setups are:

• Arrow speed: roughly 40–80 m/s for most target and hunting bows.
• Distance: 10–70 m for common field and range shots, 18 m for indoor target, and 30–70 m for many outdoor rounds.

Enter your measured arrow speed in meters per second, then enter the shot distance in meters. When you run the calculation, the tool outputs the predicted drop in meters. Some implementations additionally convert this into centimeters or inches for easier sight work; if not, you can convert manually (1 m = 100 cm ≈ 39.37 in).

Interpreting Arrow Drop Results

The computed drop value represents how far below the arrow’s original horizontal launch line the shaft will be when it reaches the specified distance. It does not automatically account for the fact that you typically aim slightly upward with your bow sight. Think of the result as a reference for how much gravity pulls the arrow down over that distance.

Some ways to use this in practice:

• Sight tape planning: Use the predicted drop at several distances (for example, 20, 30, 40, 50, 60, 70 m) to understand how quickly your point of impact falls. This helps you make sense of the spacing between marks on a sight tape.
• Pin gap intuition: A larger predicted drop between two distances means your sight pins will need to be further apart. This is one reason 20–30 m pins are close together, while 50–60 m pins can spread significantly.
• Holdover decisions: If your current sight mark is fixed (for instance, set at 20 m), you can estimate how high you may need to hold when shooting at 25 or 30 m so the arrow still lands at the center.

Always remember that the calculator’s output is an approximation based on a simplified model. You should verify any new sight setting with actual arrows on a target and adjust according to your group positions.

Worked Example: From Physics to Sight Adjustment

Suppose you are shooting a modern compound or recurve bow with an average arrow speed of 60 m/s, and you want to know the drop at 30 m. Here is how the calculator’s logic plays out step by step.

1. Inputs:
   • Arrow speed, v₀ = 60 m/s
   • Distance, x = 30 m
2. Time of flight:

   t = distance / speed = 30 / 60 = 0.5 s

3. Drop due to gravity:

   y = 0.5 × g × t² ≈ 0.5 × 9.81 × (0.5)²

   t² = 0.25, so:

   y ≈ 0.5 × 9.81 × 0.25 ≈ 1.226 m

The predicted drop is about 1.23 m at 30 m for an arrow traveling 60 m/s if it is launched perfectly horizontally. In reality, you angle the bow slightly upward when you use a 30 m sight mark, so your arrow will still land near the center. The key insight is that gravity has about half a second to act, which produces over a meter of fall without that upward aim correction.

If you prefer centimeters for sight work, multiply by 100. In this example, 1.23 m is about 123 cm of vertical drop relative to a horizontal line. Your sight adjustment compensates for that entire amount.

Typical Arrow Speeds and Drop Comparison

Different bows and arrow setups produce very different launch speeds. Lighter arrows from higher draw weight bows generally travel faster, while heavier arrows from lower draw weight bows travel slower but may carry more momentum.

The table below shows approximate arrow speeds for some common setups and how those speeds translate into relative drop at 30 m when using the same basic physics model. These numbers are rounded and intended as illustrative only.

Even over a relatively short 30 m shot, the difference in vertical drop between a slow and fast setup can exceed 1 m. This is why upgrading bow efficiency or using a lighter arrow (within safe spine limits) can noticeably tighten your pin gaps and make sight setup more forgiving.

Practical Distances and Real-World Use

Target archers frequently shoot at standardized distances: 18 m indoor, and outdoor distances such as 30, 50, 60, or 70 m depending on the round. Bowhunters typically work inside 10–40 m for ethical shot placement, though actual preferences vary by game and terrain. Within this 10–70 m band, the simplified drop model used by the calculator usually gives a reasonable approximation of how steeply your arrow is falling.

Some practical tips for turning these numbers into better shooting:

• Build a simple trajectory chart: Run the calculator at regular intervals (for example, every 5 or 10 m) and write down the predicted drop. This gives you an intuitive “arrow trajectory chart” for your personal setup.
• Align with your sight marks: When you set a new pin or mark on your sight tape (say at 40 m), compare the calculator’s predicted drop at 40 m vs. 20 m. The larger that increase, the more you should expect your pin spacing to open up.
• Validate with groups: After adjusting your sight according to stand-in numbers, shoot groups at the new distance. If the groups land high or low compared with the desired point of impact, tweak your sight and make a note of the difference.

Limitations, Assumptions, and When to Be Cautious

Like any simplified model, this calculator makes several assumptions to keep the math manageable and the tool fast. Understanding these limitations helps you avoid over-trusting the exact numeric output.

Key assumptions

• Horizontal launch: The model assumes the arrow is launched perfectly horizontally. In real shooting, your bow is angled upward to compensate for gravity, especially at longer distances.
• Level ground: It assumes that the target is at the same height as the bow. Uphill or downhill shots change the effective horizontal distance and therefore the time of flight and drop.
• No air resistance: Drag is ignored. Actual arrows slow down as they fly because of aerodynamic drag, particularly at longer ranges. This tends to increase drop compared with the idealized prediction.
• Constant gravity: Gravity is taken as a constant 9.81 m/s². This is accurate enough for archery distances and elevations but technically an approximation.
• No wind or arrow oscillation: Side winds, gusts, arrow flex (archer’s paradox), and bow torque are not included. These can shift your point of impact horizontally and vertically.
• Perfect release and tuning: The model does not account for release inconsistencies, tuning issues, cam timing, or variations in arrow mass that can introduce extra spread.

Appropriate usage ranges

The tool is most useful as a first-pass estimate for typical archery conditions:

• Arrow speeds in the range of about 30–90 m/s.
• Distances roughly between 10–70 m.

Using extremely high speeds or very long distances pushes the model outside its intended range and can yield results that no longer match real trajectories, mainly because drag grows more important as flight time increases.

Why actual sight marks differ from the model

Even if the calculator is mathematically consistent, your true sight marks will rarely match the predictions perfectly. Several factors contribute to this:

• Peep height and anchor point: The relationship between your eye, the peep sight, and the front sight housing changes how much upward angle is required for each distance.
• Arrow mass and front-of-center (FOC): Heavier or high-FOC arrows tend to retain energy differently in real air than in a vacuum model, altering the actual trajectory curve.
• Bow efficiency: Differences in cam design, string material, limb efficiency, and tuning affect how much of the bow’s stored energy becomes arrow speed.
• Environmental conditions: Air density, temperature, and altitude all influence drag and therefore arrow flight.

Treat the calculator as a way to build intuition about arrow behavior and to get in the right ballpark quickly. Always finish by fine-tuning your sight positions on the range, using real arrows and careful group analysis.

Summary

The archery arrow drop calculator combines basic projectile motion equations with your arrow speed and shot distance to estimate how far gravity pulls your arrow down in flight. While the model assumes horizontal launch, level ground, and no air resistance, it still offers valuable insight into how your point of impact changes across common hunting and target distances.

Use the outputs to understand pin gaps, set up or refine a sight tape, and plan holdover for unfamiliar distances. Then, confirm everything with actual shooting under the conditions you care about. By blending simple physics with consistent practice, you can make smarter sight adjustments and achieve more reliable accuracy on the range and in the field.