Levi's are a popular brand of jeans created by Levi Strauss and his partner, Jacob Davis, in the early 1870s. Originally worn by miners, the blue jeans quickly became a popular fashion item throughout the 20th century. Today, blue jeans are worn by people of all ages, and from all walks of life. Vintage Levi's are coveted and pricey items of clothing due to their age and historical significance. The term "vintage" refers to articles of clothing that are at least 25 to 30 years old. Levi's manufactured prior to the 1980s would be considered vintage.
Check the buttons. Levi's manufactured in the mid-1970s and prior will have a single digit stamped onto them. Newer versions (as well as fake ones) have three digits stamped on the buttons. The most popular numbers on vintage versions are 2, 5, 6 and the letter W. New Levi's have "501" or "555" stamped on them.
Look at the rivets. Older styles from the mid-1960s to the 1980s feature flat silver rivets with L.S.&CO-S.F. indented on them. Newer styles feature aluminum or copper rivets with circular patterns and L.S.&CO-S.F. indented on them. The circular patterns on the rivets are a sure sign that the Levi's are relatively new.
Check the red tab. This is a small red fabric tag that has "Levi's" written in white in all caps. Prior to 1971 the "e" in Levi's was capitalized and referred to as the "big E." After 1971, the "e" was written in lower case while the other letters were left capitalized.
Read the care tags. They first appeared on Levi's in the 1970s. The tags from 1970 to 1985 were plain white with dark blue writing and contained an instruction that read "Shrinks about 10%." Newer jeans (after 1985) have care tags that are white with red writing and the Levi's logo placed prominently at the top. The older versions do not have a Levi's logo on the care tags.
Inspect the inseam and back pockets. The style of inseam on almost all Levi's before the mid-1980s featured a single felled inseam, which is a single stitch running down the inner thigh. The back pockets on vintage Levi's have a very pronounced arcuate design. An arcuate is denoted by two wide arcs joined together in the middle, similar to the top part of a traditional heart shape. On newer Levi's the arcs are much more shallow.
Check for bar tacks at the corners of the pockets. Bar tacks are a method of sewing that involves using extra thread to reinforce a thicker fabric such as denim. Levi's that contain bar tacks on the corner pockets are at least 20 years old and may be even older.
Make sure a pair of Levi's has at least two of the mentioned identifying marks before you classify them as vintage.