Arm lymphedema is routinely assessed by clinicians and researchers, using arm circumference measurements. A protocol was developed for measuring arm circumference independent of medically trained professionals. The aim of this project was to assess the protocol's inter-rater reliability and its coherence with perometry measures.Community-dwelling adults (n = 57), aged 60.2 ± 12.8 years, in good general health, were included in this study. Circumference of both arms were measured at the ulnar styloid of the wrist and at four 10 cm intervals up the arm by a friend of the participant, as well as the trained assessor using a tape measure. The same measures were also obtained with a perometer. The assessment tools had moderate to high concordance (r(c) = 0.84-0.94 for assessor vs. perometer and r(c) = 0.68-0.93 for assessor vs. participant). Limits of agreement analysis revealed that the mean difference between methods varied based on the measurement location; the bias ranged from -5.5% to 1.5% for assessor-measured vs. perometer methods and from -2.4% to 4.0% for assessor-measured vs. participant-measured methods.The written instructions and cartoons are reliable tools that could be used by women at risk of lymphedema as well as those with lymphedema following treatment for breast cancer to measure their arm circumference reliably independent of medically trained personnel.