When your arrows group well but land off center, your sight needs moving, and this calculator tells you how far and which way. You enter the distance, how far your group misses vertically and horizontally, and your sight radius, and the tool gives the sight movement in centimeters and in clicks. No more guessing with the sight screws and hoping the next group lands closer. Measure the miss, move the sight, and confirm with the next group.
The rule to remember is simple: follow the arrow. If your arrows hit high, move the sight up. If they hit right, move the sight right. This feels backwards to many beginners, who expect to move the sight away from the miss, but following the arrow is correct for a standard sight. Moving the sight toward the impact shifts your aim so the next group centers. Write the rule on your quiver if you keep forgetting it under pressure.
The math behind the tool is a simple ratio. The sight sits much closer to you than the target, so a small sight movement produces a larger shift at the target. The movement equals your miss times the sight radius divided by the distance, with units matched. At 30 metres with an 80 centimeter sight radius, an 8 centimeter high group needs a sight move of about 0.21 centimeters, or roughly two clicks at one millimeter per click. Small numbers are normal, so do not be surprised when the answer looks tiny.
Measure your miss from the center of your group, not from your worst arrow. Shoot at least three, ideally six arrows, find the middle of the group, and measure from there to the center of the target. A single wild arrow can mislead you into a bad adjustment, while a group center gives a trustworthy number. If your group is scattered with no clear center, fix your form first, because no sight adjustment can correct inconsistent shooting.
Sight radius matters, so measure yours correctly. It is the distance from your eye to the sight pin, roughly your draw length plus the sight extension, and most recurve setups fall between 70 and 90 centimeters. A longer sight radius means smaller, finer adjustments, which is one reason target archers use extended sights. Enter your best estimate; a small error here changes the answer only slightly, and you will confirm with the next group anyway.
Always confirm after adjusting. Move the sight by the calculated amount, shoot a fresh group, and check whether it centers. Wind, lighting, and fatigue all shift impacts slightly, so a perfect calculation can still leave a small error on the day. Adjust in small steps rather than chasing every arrow, and keep notes on your sight settings for each distance. Those notes become your personal sight tape over time.
This tool is a planning and practice aid for recreational archery. It does not replace coaching, and it cannot diagnose form problems that look like sight problems. If your groups stay wide after correct adjustments, ask a coach to check your release and alignment. But when your groups are tight and just off center, this calculator turns a frustrating guessing game into one measured move.
Sight marks for different distances are worth recording once your adjustments are dialed in. Most archers keep a small notebook or a tape on the sight bar showing the sight position for each distance they shoot, such as 20, 30, 50, and 70 metres. When you move to a new distance, set the sight to the recorded mark, shoot a group, and use this calculator for any small correction. Over a season, those recorded marks save time at every shoot and reveal patterns, like a sight that always needs a click left on windy days. A notebook plus this calculator turns sight setup from a chore into a two-minute routine.