Brand comparisons usually run on opinion. This one runs on settled transactions: 400 recorded sales of Piaget and 203 of Longines, all in US dollars so the figures are directly comparable.
What each one actually costs
The median Piaget result is $5,250. The median Longines result is $2,500. On typical examples, Piaget carries roughly 2.1 times the price of Longines at auction.
Half of all Piaget sales land between $3,570 and $10,240. For Longines the middle half runs $1,250 to $6,875.
Which one surprises the specialists
41% of Piaget lots beat their high estimate, against 34% for Longines. The two are closely matched, which suggests both are priced with similar confidence.
Breadth of the record
Our archive covers 156 distinct Piaget references and 61 for Longines, with results going back to 2001 and 2004 respectively. The top recorded result is $602,500 for Piaget and $106,680 for Longines.
What this does not tell you
A median is not a verdict. These brands overlap heavily at the edges, and a well chosen example of the cheaper one will outrun a poor example of the dearer one. Condition, completeness and model matter more than the badge on the dial.