The pēchus is the New Testament equivalent of the cubit (’amah in Hebrew).
In most cases the translator will be able to avoid awkward fractions and decimal points for the pēchus by using the formula, two cubits equal one meter or one yard.
MAT 6:27; LUK 12:25: One problem of interpretation here is that the Greek word pēchus is normally used of distance rather than of time. However, it may also be used of time, and that meaning is much more satisfactory in the present context. Moreover, the Greek word rendered “span of life” by RSV is more frequently used as a measurement of time than height. Modern translations tend to accept the meaning of a measure of time. If span is used as a measurement of time, the use of the word pēchus to qualify it would mean a brief span, whereas if it is used of a person’s height, it would be a significant amount (about half a meter or 18 inches). NAB renders the last part of MAT 6:27 as “add a moment to his life-span,” and GECL has “lengthen his life only by one day.” Other possibilities are “add a little time to his life,” “live a little longer,” and “make his life last even a little longer.” Some translators will indicate a specific amount of time, such as “even one day” or “even one hour.”
JHN 21:8: The distance given here is approximately 100 meters or 100 yards. Translators will want to follow something like CEV “only about a hundred yards from shore.”
REV 21:17: The text gives a measurement of 144 cubits, that is, twelve times twelve. This seems to be a symbolic number, and many translations—among them common-language translations such as GWNCVITCLGECL —choose to leave the number in the text. ITCL also adds the metric equivalent in the text, saying “one hundred forty-four cubits (seventy meters).”
GNT takes this measurement, 144 cubits (72 meters; 236 feet), to be the height of the wall (also NJBREBFRCL, Phps). It may, however, refer to its thickness (NIVBRCL). Some commentators make the point that, for a city that is 1,500 miles tall, a wall only 72 meters (236 feet) tall is so small that it seems foolish. But it is also pointed out that the wall, in this case, is not for the protection of the city (inasmuch as the gates stay open all the time) but for its demarcation. In any case, the notion of height is preferable to that of thickness. A translation should opt for one or the other; simply to say, as RSV and others say, “a hundred and forty-four cubits” (or, “72 meters” or “236 feet”), without indicating that this is the height, does not qualify as a translation. An alternative translation model for the first half of this verse is “He also determined the height [or, thickness] of the wall [or, fence]. It was 72 meters [or, 236 feet].” For this verse see also A Handbook on The Revelation to John, pages 306–307.