Measurements

LENGTHS

ah-il, ah-ral

"Cloth is measured in the ah-il, which is the length from the elbow to the tip of the middle finger, and the ah-ral, which is ten ah-ils."
Tribesmen of Gor, page 50

Hort = 1 and 1/4 inches

"The hort is approximately and inch and a quarter in length."
Tribesmen of Gor, page 49

Gorean Foot = 10 horts, approxiamtely 12 1/2 inches

"The Gorean foot, is in my estimation, just slightly longer than the Earth foot; based on the supposition that each of its ten horts is roughly one and one-quarter inches long, I would give the Gorean foot a length of roughly twelve and one-half inches, Earth measure."
Raiders of Gor, pages 127-128

pasang = 0.7 miles

"The pasang is a measure of distance on Gor, equivalent approximately to 0.7 of a mile."
Tarnsman of Gor, page 58

WEIGHTS AND VOLUMES

gill = liquid volume

"In a matter of perhaps two or three seconds, it had drawn perhaps a gill of liquid."
Outlaw of Gor, page 34

Stone = 4 Earth pounds

"I have calculated this from the Weight, a Gorean unit of measurement based on the Stone, which is about four Earth pounds."
Raiders of Gor, page 127

TEF, TEFA, HUDA

tef = handful, fingers closed
tefa = 6 tef
huda = 5 tefa

"A handful with the five fingers closed, not open, is a tef. Six such handfuls constitute a tefa, which is a tiny basket. Five such baskets constitute a huda."
Tribesmen of Gor, page 46

Weight = 10 Stone = 40 Earth pounds

"A given tree, annually, yields between one and five Gorean weights of fruit. A weight is some ten stone, or some forty Earth pounds."
Tribesmen of Gor, page 37

"I have calculated this from the Weight, a Gorean unit of measurement based on the Stone, which is about four Earth pounds. A Weight is ten Stone."
Raiders of Gor, page 127

MONEY

"For example, a 'double tarn' is twice the weight of a 'tarn'. It seems there are usually eight tarsk bits in a copper tarsk, and that these are the result of cutting a circular coin in half, and then the halves in half, and then each of these halves in half. An analogy would be cutting the round, flat Gorean loaves of Sa-Tarna bread into eight pieces. There are approximately something like one hundred copper tarsks in a silver tarsk in many cities. Similarly, something like ten silver tarsks would apparently be equivalent, depending on weights, etc., to one gold piece, say, a single 'tarn'. Accordingly on this approach, the equivalencies, very approximately and probably only for certain cities, would be eight tarsk bits to the copper tarsk, one hundred copper tarsks to a silver tarsk, and ten silver tarsks to a gold piece, a single tarn. On this approach, there would be, literally, 8,000 tarsk bits in a single gold piece."
Magicians of Gor, footnotes, page 469

So, using this formula,
8 copper tarks bits = 1 copper tarsk
100 copper tarsks = 1 silver tarsk
10 silver tarsks = 1 gold tarn

"Without speaking, the man took twenty pieces of gold, tarn disks of Ar, of double weight, and gave them to Kuurus..." Assassin of Gor, page 4

Now, in an earlier book, the author mentions silver tarn disks (as opposed to tarsks). These are valued a little differently apparently...(or it could be the differences in the cities, as cited in the first quote); but the quotes do seem contradictory

"Actually, fifty silver tarn disks was an extremely high price, and indicated the girl was probably of high caste as well as extremely beautiful. An ordinary girl, of low caste, comely but untrained, might, depending on the market, sell for as little as five or as many as thirty tarn disks."
Outlaw of Gor, page 193

"A golden tarn disk was a small fortune. It would buy one of the great birds themselves, or as many as five slave girls."
Tarnsman of Gor, page 191