Durnin & Womersley 4 Site Calipers Good general caliper formula, especially when using the classic four upper-body sites.
Jackson-Pollock 3 Site Calipers Fast skinfold option; useful for consistency, but less complete than 7-site.
Jackson-Pollock 7 Site Recommended Calipers Recommended caliper choice: most complete skinfold coverage in this app.
US Navy Circumference Recommended Tape measure Recommended tape-measure option; generally stronger than waist-only estimates.
YMCA Circumference Tape measure Quick estimate from waist and weight; convenient, but more approximate.