Bow Sight Tape Calculator

What a sight tape does

A sight tape is the strip of paper or printed scale that runs alongside your bow sight slider. You set your zero pin (often 20 yards), then the tape tells you exactly where to slide the sight for any other distance, 40, 60, 73, without needing a separate pin for every yardage. Field archery and 3D shooting both depend on it. A good tape turns a single-pin slider into the most precise sight system on the line.

How the math works

For each target distance the calculator works out the flight time using your chronographed arrow speed (with a small drag correction), then computes the gravity drop from d = ½ × g × t². Dividing that drop by the distance gives the aiming-angle correction the pin must make, and your zero mark calibrates how many millimeters of sight travel one unit of angle costs on your particular sight.

The tape is not evenly spaced, but the stretch is mild: the gap between the 60- and 70-yard marks runs roughly 20-60% wider than the 20-to-30 gap, depending on arrow speed. Raw drop grows with the square of flight time, but because the sight corrects an angle (drop divided by distance), most of that square cancels out. What keeps the marks from being perfectly even is drag: the arrow is slower over the long shots.

Verifying against real shots

A printed tape is a starting point, not a finished tool. After you generate one, shoot a known-distance target at three or four points across your range, usually 20, 40, and 60 yards. If you are hitting an inch low at 60, slide the tape down a hair and re-tape. Most field archers go through two or three iterations before a tape is fully dialed.

Common gotchas

• Heavy hunting arrows produce a different tape than light target arrows, even on the same bow
• Switching points or fletching changes drag and bumps the tape a few millimeters
• Cold morning air is denser and slows arrows slightly, so winter tournament tapes drift hot from a summer tape
• Re-chrono whenever you change a setup component, restring the bow, or notice the tape has gone stale

A tape from this calculator should put you on paper at every distance on the first shoot, with the long marks needing at most a few millimeters of nudging. If you are wildly off, double-check the chrono number and the zero distance you entered.