Home Bow Tuning How to Sight In a Compound Bow
How to Sight In a Compound Bow
The complete step-by-step process — from first shot at 10 yards to a verified 5-pin setup at distance. Includes the Pin Gap Calculator: enter your arrow speed and weight and get the exact physical spacing between each pin on your sight, before you shoot a single arrow.
Quick navigation: Pin Gap Calculator · Step-by-Step Guide · Why Gaps Are Unequal · Chasing the Arrow · Common Mistakes · FAQs
Enter your arrow speed, arrow weight, and the distance for each pin. The calculator uses a physics-based trajectory model (exponential drag decay + bore-rise compensation) to return the exact spacing in inches and millimetres between adjacent pins — so you arrive at the range already close.
💡 Calculated gaps are starting positions — range verification by shooting is always required. Actual positions vary slightly with anchor consistency and bow efficiency. For maximum precision, chronograph your arrow speed.
🎯 Building your complete sight setup? This calculator is one piece of the process:
- Step 1: Peep Sight Height Calculator — set the rear aperture before touching any pins
- Step 2: Pin Gap Calculator — you are here
- Step 3: Sight Mark Calculator — verify all pin positions
- Step 4: Broadhead Tuning — confirm broadheads group with field points before hunting
Step-by-Step: How to Sight In a Compound Bow
This sequence works for any multi-pin compound bow sight. Follow it every time you change your sight, swap arrow weights, or adjust draw weight by more than 3 lbs. Complete the pre-flight checklist before touching any pin — skipping it is the single most common reason archers spend twice as long at the range.
🔍 Pre-flight checklist — complete before adjusting any pin:
- Arrow rest height and centershot are set and paper-tuned — see the Compound Bow Tuning Guide.
- Peep sight is installed at the correct height and not rotating — use the Peep Sight Calculator.
- D-loop is tied correctly and not creeping; nocking point is firm.
- All sight screws are snug: housing bolt, windage lock, elevation lock, and individual pin-lock screws.
- You are shooting the arrows you will hunt or compete with — verify spine with the Arrow Spine Calculator.
Why Pin Gaps Are Not Equal — The Physics Explained
The most common question from archers setting up a multi-pin sight for the first time: "Why is the space between my 20 and 30 yard pins smaller than between my 30 and 40 yard pins?" And the follow-up: "My gaps look wrong — are they?"
They are not wrong. The answer is physics. Your arrow does not slow down at a constant rate, and gravity does not pull it down at a constant rate relative to horizontal distance. As the arrow travels further, it loses speed — and a slower arrow falls more per yard than a fast one. This produces a parabolic, not linear, trajectory. The gap between pins must grow with distance because each additional 10 yards of travel involves more drop than the previous 10 yards.
Here is what the gap pattern looks like for a typical 280 fps / 430 grain setup, zeroed at 20 yards, on a standard 1:1 scale sight:
| Pin span | Physical gap on sight | Cumulative drop from 20-yd impact | Gap growth from previous span |
|---|---|---|---|
| 20 → 30 yards | ~0.45" | ~3.5" | — (reference) |
| 30 → 40 yards | ~0.62" | ~8.5" | +0.17" wider than 20→30 |
| 40 → 50 yards | ~0.80" | ~16" | +0.18" wider than 30→40 |
| 50 → 60 yards | ~1.00" | ~26" | +0.20" wider than 40→50 |
The specific numbers depend on your arrow speed, arrow weight, sight scale factor, and zero distance. That is exactly what the Pin Gap Calculator above solves. It takes your parameters and returns the exact spacing for each of your pins, so you arrive at the range with pins already in approximately the right position.
How arrow speed changes your gaps
A faster arrow (300+ fps) maintains velocity further and drops less per yard — gaps are tighter and more uniform-looking. A slower arrow (under 240 fps) loses speed quickly and gaps widen dramatically at distance. A 280 fps setup and a 220 fps setup have visually very different pin spacing on the same sight. Both are correct for their respective arrows. This is why you cannot use another archer's sight settings even if you shoot the same distances — unless you have exactly the same arrow speed and weight.
How arrow weight changes your gaps
Heavier arrows are harder to push to the same speed, but they also retain velocity better once launched. A 520-grain arrow decelerates more slowly than a 350-grain arrow at the same initial speed because it carries more momentum per unit of cross-sectional area. This means heavier hunting arrows have slightly wider initial gaps (they leave slower) but the gaps widen less dramatically at longer distances compared to an ultra-light arrow at the same fps.
Get accurate speed figures before calculating
The Pin Gap Calculator is only as accurate as the arrow speed you enter. A 20 fps difference moves your 50-yard pin by 2–3mm — noticeable at distance. If you do not have a chronograph reading, the Arrow Speed Calculator estimates your speed from IBO rating, draw weight, draw length, and arrow weight.
For the most reliable pin setup, chronograph your exact hunting arrow before the sighting-in session. Shop archery chronographs on Amazon →
Fixed Multi-Pin vs Single-Pin Adjustable — Which Sight Type Is Right for You?
This page and the Pin Gap Calculator serve fixed multi-pin sights. Before spending time on setup, confirm you have the right sight type for your application.
| Feature | Fixed multi-pin | Single-pin adjustable |
|---|---|---|
| Ready for any distance instantly | ✅ Yes — aim the right pin | ❌ Must dial the distance before drawing |
| Best for hunting moving game | ✅ Preferred | ⚠️ Risk of forgetting to dial the distance |
| Best for target / known distance | ⚠️ Cluttered sight picture beyond 50 yds | ✅ Preferred |
| Sight picture simplicity | ⚠️ Multiple pins visible simultaneously | ✅ One pin only |
| Setup tool on this site | ✅ Pin Gap Calculator above | Sight Tape Calculator |
| Typical user | Bowhunters, 3D archers | Target archers, indoor competitors |
If you use a single-pin adjustable sight, the Sight Tape Calculator generates a complete printed tape for your exact arrow speed and weight — the equivalent of the Pin Gap Calculator for that sight type. The Sight Mark Calculator works for both sight types and lets you verify positions at any distance.
Chasing the Arrow — The One Rule That Confuses Every Beginner
Every sighting-in mistake traces back to one source of confusion: which direction do I move the sight? The rule is simple but counterintuitive the first time you hear it:
If arrows are hitting left of centre at 20 yards, move your sight housing to the left. If arrows are hitting high, move the housing up. This feels backward — you might expect to adjust the aiming point away from the error — but sight adjustment does not work that way. You are moving the physical reference point (the pin) toward where your arrow naturally wants to go.
Why this works: Moving the sight left shifts the pin to the left. To aim that pin at the centre of the target, you now have to point the bow slightly to the right. That new aiming direction carries the arrow to the right — toward centre. Move far enough, and pin centre and arrow impact centre are the same point.
Housing vs individual pin — which to move when
Move the housing only during the initial 20-yard zero — it shifts every pin simultaneously. Move individual pins for each distance after that. Once lower pins are set and verified, the housing must never move. Touching it will shift your 20-yard reference off centre and require starting over.
How far to move the sight
On a 1:1 scale sight, if arrows are 3 inches right at 20 yards, move the sight approximately 3 inches right. The relationship is not perfectly 1:1 due to geometry, but it is close enough to get you to centre in one or two adjustments rather than ten.
Why groups scatter more at distance
Any form inconsistency — grip torque, anchor variation, trigger anticipation — is amplified at distance. Tight groups at 20 yards but scattered at 40 means the sight is not the issue: form, arrow spine, or bow tune is. Verify with the Compound Bow Tuning Guide before adjusting pins.
When to stop adjusting a pin
Three arrows in a 3-inch circle at the target distance means the pin is close enough. Two consecutive 3-arrow groups at the same location means it is confirmed. Never chase a single flyer — outlier arrows are almost always form, not sight position. Adjust for the group, not the stray.
Worked Example: 280 fps / 430 gr Setup, 5-Pin Sight
Here is a complete example of the calculator output and how it translates to range verification, using a typical compound hunting setup.
| Pin | Distance | Down from Pin 1 (calculated) | Gap from previous pin | Speed at distance |
|---|---|---|---|---|
| Pin 1 | 20 yards | 0.000" (reference) | — | ~272 fps |
| Pin 2 | 30 yards | ↓ 0.451" | 0.451" | ~264 fps |
| Pin 3 | 40 yards | ↓ 1.073" | 0.622" | ~257 fps |
| Pin 4 | 50 yards | ↓ 1.876" | 0.803" | ~250 fps |
| Pin 5 | 60 yards | ↓ 2.877" | 1.001" | ~243 fps |
Notice that the gap grows from 0.45" (20→30) to 1.00" (50→60). Equal spacing would mean every gap is ~0.72" — which is wrong for every single distance except somewhere around 35 yards. If your current sight has equal spacing, your 50 and 60-yard pins are incorrect.
At the range, each pin in this example needed between 2 and 5 confirmation arrows to verify. Compare that to starting blind (no calculator) — where 10–20 arrows per pin is typical.
5 Most Common Sighting-In Mistakes
Sighting In for Hunting vs Target Archery — What Changes
The mechanical process described above applies to both disciplines. The priorities are different.
Hunting setup: Verify your top pin at the distance where you are most likely to shoot — typically 20 or 25 yards for treestand hunting. Your farthest pin should represent your self-imposed maximum ethical distance, not the physical limit of the sight. Confirm that fixed-blade broadheads group with field points before season — see the Broadhead Tuning Guide. Test your sight in low light, in full hunting kit, and from your actual stand or blind position before opening day.
3D archery: Most 3D archers use either fixed multi-pin (typically 3 pins at practical field distances — 10, 20, 30 yards) or a single-pin adjustable. For multi-pin 3D, use the Pin Gap Calculator for your specific arrow speed to set starting positions. The Shot Angle Calculator helps compensate for uphill and downhill animal placement common on 3D courses.
Indoor / outdoor target: Most target archers use a single-pin adjustable sight rather than fixed multi-pin. For single-pin setup, use the Sight Tape Calculator to generate a complete tape. For outdoor target at known distances (18m, 25m, 50m, 70m), the Sight Mark Calculator generates verified pin positions for any distance.
Frequently Asked Questions
Why is the gap between my 20 and 30 yard pins smaller than between my 30 and 40?
Arrow trajectory is parabolic, not linear. As the arrow travels further, it slows down — and a slower arrow falls more per yard than a fast one. The 30-to-40 gap is always larger than the 20-to-30 gap, and the 40-to-50 gap is larger still. This non-linear spacing is physics, not an error in your sight setup. The Pin Gap Calculator above quantifies exactly how much larger each gap should be for your specific arrow speed and weight.
Should I move the sight in the same direction as where my arrows hit?
Yes — always chase the group. Move the sight housing toward where arrows are hitting. If arrows hit left, move the sight left. If arrows hit high, move the sight up. This feels counterintuitive but is the correct adjustment direction for all bow sights. See the Chasing the Arrow section above for the full explanation of why this works.
How many pins should a compound bow sight have?
Most hunters use 3–5 pins set for their most likely shot distances — typically 20, 30, 40, and sometimes 50 and 60 yards. More pins give more distance coverage but create a cluttered sight picture that can cause confusion in low-light conditions. If you consistently limit ethical shots to under 40 yards, 3 pins are sufficient and the sight picture is cleaner. For 3D archery or long-range target, a single-pin adjustable sight is often the better tool.
Do I need to re-sight after changing arrow weight?
Yes, if the change is 25 grains or more. A heavier arrow flies slower and drops more at distance — all pin gaps change. A lighter arrow does the opposite. Even if your top pin at 20 yards is only slightly off, lower pins at 40–60 yards will be noticeably wrong. Always re-verify at distance after changing arrow weight, point weight, or draw weight by more than 2–3 lbs. Run the Pin Gap Calculator again with the new arrow weight to get updated starting positions.
How long does it take to sight in a compound bow?
A complete 5-pin sight-in takes one range session of 1–2 hours using the Pin Gap Calculator for starting positions. Expect to shoot 60–100 arrows total. Starting completely blind (no calculator) typically takes 150–200 arrows for the same result. Having your arrow speed from a chronograph before the session makes everything faster and more accurate.
Can I sight in a compound bow without a chronograph?
Yes. The Pin Gap Calculator accepts a speed estimate from the Arrow Speed Calculator if you do not have a chronograph reading. The starting positions will be approximate rather than precise, but still far better than guessing. Since you confirm each pin by shooting at distance regardless, a small initial error is corrected automatically during the process. A chronograph is the single most useful accessory for this process if you do not already own one.
What is the difference between moving the sight housing and moving an individual pin?
Moving the housing adjusts every pin simultaneously by the same amount. It is used only for the initial 20-yard zero. Moving an individual pin adjusts only that pin's setting — it has no effect on any other pin. Once you have zeroed your top pin and started verifying lower pins, only individual pins should ever move. Touching the housing again will shift your 20-yard reference and invalidate every lower pin you have already set.
Why do broadheads hit a different spot than field points?
Fixed-blade broadheads behave like small aerodynamic surfaces on the arrow. Any bow-tune issue — rest position, arrow spine mismatch, nocking point error — that field points forgive at 20 yards will be amplified by a broadhead at 40 yards. If broadheads group away from field points, the bow needs tuning before the sight settings are reliable for hunting. See the Broadhead Tuning Guide for the full diagnostic and fix sequence.
How does the Pin Gap Calculator's physics model work?
The calculator uses exponential drag decay — v(d) = v₀ × e^(−k×d) — where the decay constant k is adjusted for your arrow's weight relative to a 450-grain reference (heavier arrows retain speed longer). Time of flight is computed via 6-segment numeric integration for accuracy. Raw gravity drop is then corrected for bore-rise compensation: the upward aim angle built into the bow at the zero distance. The net offset is divided by your sight's scale factor to give physical sight-body movement in inches and millimetres. This is why it is more accurate than a simple parabola model, especially at distances beyond 40 yards.
My sight does not have enough travel to fit all my pins. What do I do?
This typically happens with faster arrows (300+ fps) where pin gaps are tighter, or when using a very short zero distance. Options: switch to a sight housing with a longer adjustment range (sometimes called an extended gang bar), reduce the number of pins and use a shorter maximum distance, or — for hunting — honestly reassess whether your maximum ethical distance is as long as you think it should be. Many experienced hunters limit themselves to 3 pins at 20, 30, and 40 yards and practice those distances intensively rather than maintaining 5 pins at longer ranges.