diff --git a/fpdf.go b/fpdf.go
index 5ac99dd..ab06c4a 100644
--- a/fpdf.go
+++ b/fpdf.go
@@ -126,7 +126,7 @@ func fpdfNew(orientationStr, unitStr, sizeStr, fontDirStr string, size SizeType)
 	case "pt", "point":
 		f.k = 1.0
 	case "mm":
-		f.k = 72.0 / 25.4
+		a = 72.0 / 25.4
 	case "cm":
 		f.k = 72.0 / 2.54
 	case "in", "inch":
@@ -3503,7 +3503,7 @@ func (f *Fpdf) getpagesizestr(sizeStr string) (size SizeType) {
 				f.err = fmt.Errorf("unknown page size %s", sizeStr)
 			}
 		}
-		size, ok = SizeType{aFloat[0], aFloat[1]}, false
+		size, ok = SizeType{aFloat[0] * f.k, aFloat[1] * f.k}, true
 	} else {
 		//20210302 archium addendum end
 		size, ok = f.stdPageSizes[sizeStr]