What it is
Power is your target speed. You set it as how far past the hole you want the ball to finish, from deadweight – dropping in the hole with the last turn, to three feet past. Change the Power and the app redraws the lines for that speed.
Why it changes your putt
Let’s do an excursion into basic physics. The break of a putt is determined mainly by four factors: its distance, gradient, green speed, and power – if we neglect external factors like weather and grain (learn more on their influence here). As distance and gradient are given for a specific putt, green speed and power remain the only variables in this equation. We want to focus on power here, so we assume your green is running at stimp 10.
If you want your putt now to finish 3 feet past the hole, you would need to hit it harder – and more ball speed means more inertia to hold the line against gravity, causing the ball to break less. For a 10-foot putt on a 2% slope, that would mean you have to aim 6.5 inches outside the edge of the cup.
If you want your putt now to finish 0 feet past the hole, dropping in just with the last turn, you would need to hit it much softer, giving gravity more chance to pull the ball down the slope and therefore causing the ball to break much more. For a 10-foot putt on a 2% slope, that would mean you have to aim 9.5 inches outside the edge of the cup.
What to do with it
This example shows why it is so important to find your preferred power and correctly set it within the PuttView app. It is in fact the second-most important setting for line accuracy within the app.