The standard penetration test (SPT) is commonly used for site characterisation in geotechnical engineering. This geotechnical parameter obtained from SPT is called “N-value”. This is a non-dimensional value of count of blows of a cone of a standardised size, shape and material to penetrate a standardised depth driven by a standardised force. These standards are rather arbitrary decided and the specification is enshrined in ASTM D1586/D1586M-18e1. This value is indicative of the hardness of ground material and various conditions at the time of the SPT survey. The multi-channel analysis of seismic waves (MASW) method estimates S-wave velocity structure. The S-wave velocity is a physical property of the material indicative of its hardness. Therefore, there is some correlation between the S-wave velocity and the N-value. As seismic surveys are conducted along survey lines, the distribution of S-wave velocity is expressed as 2-dimensional sections. This contrasts with the SPT which measures N-values only along the depth axis at one drill location. Seismic surveys are generally less expensive than SPT surveys for the same data density. It is not invasive to the ground of the sites. Many researchers attempted to find relationships between these parameters resulting in about thirty formulae have been proposed from many places for different environments ([1]). Some of them are from collection of several locations and others are site-specific. Inevitably, these formulae do not exactly convert S-wave velocity to N-value: there is always some estimation error. With any of these formulae, comparison between different sites is impossible. The formula for pseudo-N value was first proposed in 2011 as N=(60/Vs)^2.5 ([2]). N-values are estimated along survey lines. By using this formula as a standard, with understanding of existence of error, the results can be compared from site to site. This presentation shows examples of use of pseudo-N values.