

Ancient Hebrew units of length or distance are mentioned in the Bible, but their values in terms of modern units are open to some speculation. The only way of determining the length of any Ancient Hebrew unit would be to measure something in modern terms whose length was given by the Hebrews in their units. Unlike the Attic Greek and Ancient Roman units, there are not good examples of such measurable objects, so much of the information we have is based on guesswork. According to Cardarelli^{[1]} they are based upon two different standards:
Name of unit  Value in terms of smaller units  Value in terms of the meter (sacred system)  Value in terms of United States customary measure (sacred system)  Value in terms of the meter (secular system)  Value in terms of United States customary measure (secular system) 

finger  0.02667  1.0499 in. = 0.0875 ft  0.023125  0.9104 in.  
palm  4 fingers  0.10667  4.1995 in. = 0.35 ft  0.0925  3.6417 in. = 0.3035 ft 
zereth  3 palms  0.320  1.05 ft = 0.35 yd  0.2775  10.925 in. = 0.91 ft 
cubit  2 zaroth  0.640  2.1 ft = 0.7 yd  0.555  1.821 ft = 0.607 yd 
The table in Wikipedia is somewhat different, giving a range, which includes Cardarelli's secular values near the upper limit, but does not reach his values for the sacred system:
Name (Plural)  Hebrew Name (Plural)  Translation  Size in terms of smaller units  Size (Metric)  Size (English)  Notes 

Etzba (Etzba'ot)  אצבע
(אצבעות)  thumbbreadth  2–2.4 cm  0.79–0.94 in  The latter value is Chazon Ish's. Since all other units are multiples of the etzba, they vary accordingly.  
Tefach (Tefachim)  (טפח (טפחים  handbreadth  4 fingerbreadths (Etzba'ot)  8–9.6 cm  3.15–3.78 in  
Zeret (Zarot)  (זרת (זרות  span  3 palms (Tefahim)  24.0–28.8 cm  9.45–11.34 in  
Amah (Amot)  (אמה (אמות  cubit  2 spans (Zeret)  48.0–57.6 cm  18.9–22.7 in  
Ris  stadium  266⅔ ells (Amot)  128–153.6 m  139–167 yd  
Mil (Milin)  mile  2000 ells (Amot)  960–1152 m  1049–1258 yd  Time to walk a mil is 18 minutes.  
Parasa (Parsa'ot)  parasang  4 mils (Milin)  3.84–4.608 km  2.4–2.88 mi  Distance covered by an average man in a day's walk is 10 parsa'ot. Time to walk a parasa is 72 minutes. 
It should be noted that the transliterations are according to the modern Israeli pronunciation, accounting for the difference between zeret and Cardarelli's zereth, which more closely approximates the pronunciation in ancient times. Also, the mil and parasa are importations, the former from Roman usage, the latter from Persian.
ReferencesEdit
 ↑ Cardarelli, François (1998). Scientific Unit Conversion. Berlin, Heidelberg, New York: SpringerVerlag. ISBN 3540760229.