The most accurate way to measure body

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I have a Health-o-Meter digital tape measure and, of course, several cloth and/or plastic tape measures, including Myo-Tape. I get about 1 inch less on my waist with the digital. The cloth measures are both the same and one is different yet. I know that many tapes do get out of shape, they stretch.

My question does anyone know for "sure" which is the most accurate way to get true measurements.