Your Swatch
Gauge is quoted over 4 inches in US patterns and 10 cm in UK and European ones. They are close but not identical — 10 cm is 3.94 in.
Pattern gauge
Copy these from the pattern exactly, including the stitch it specifies.
Your gauge
Measure across the middle of a swatch at least 6 in / 15 cm square. Never measure the edges.
Result