A feeler gauge for measuring the thickness of a gap, the gauge comprising: a plurality of measuring leaves rotatably coupled along a common axis of rotation and being selectively movable between a home position and an extended position, wherein each measuring leaf defines an elongate, substantially flat shape defining a leaf thickness, and wherein one or more extended leaves can be inserted into the gap such that the combined leaf thickness of the one or more extended leaves substantially corresponds to the thickness of the gap; and a measurement determination mechanism configured to determine the thickness of the gap by at least one of detecting which of the leaves are in the extended position and calculating the thickness, detecting which of the leaves are in the home position and calculating the thickness, measuring the total thickness of the leaves in the extended position, and measuring the total thickness of the leaves in the home position; wherein the gauge is configured to perform at least one of display the thickness, transmit a signal representing the thickness to a computing device, store the thickness locally for later processing, and provide user notification; the gauge further comprising a housing , wherein the housing includes an upper member , a lower member and an interior cavity between the upper and lower members, and wherein a leaf is in the home position when the leaf is oriented about the axis of rotation such that the leaf is positioned substantially in the interior cavity of the housing characterized in that the measurement determination mechanism includes a compression member configured to apply a compressive force to a portion of the leaves in the home position distal the axis of rotation of a degree sufficient to at least substantially eliminate space between the portion of the leaves . a plurality of measuring leaves rotatably coupled along a common axis of rotation and being selectively movable between a home position and an extended position, wherein each measuring leaf defines an elongate, substantially flat shape defining a leaf thickness, and wherein one or more extended leaves can be inserted into the gap such that the combined leaf thickness of the one or more extended leaves substantially corresponds to the thickness of the gap; and a measurement determination mechanism configured to determine the thickness of the gap by at least one of detecting which of the leaves are in the extended position and calculating the thickness, detecting which of the leaves are in the home position and calculating the thickness, measuring the total thickness of the leaves in the extended position, and measuring the total thickness of the leaves in the home position; wherein the gauge is configured to perform at least one of display the thickness, transmit a signal representing the thickness to a computing device, store the thickness locally for later processing, and provide user notification; the gauge further comprising a housing , wherein the housing includes an upper member , a lower member and an interior cavity between the upper and lower members, and wherein a leaf is in the home position when the leaf is oriented about the axis of rotation such that the leaf is positioned substantially in the interior cavity of the housing characterized in that the measurement determination mechanism includes a compression member configured to apply a compressive force to a portion of the leaves in the home position distal the axis of rotation of a degree sufficient to at least substantially eliminate space between the portion of the leaves . <EOS>