One kryddmått is exactly 1 millilitre. The two are the same volume, which makes this the only conversion in the cooking category where the answer is simply the number you started with.
About the units
The kryddmått — literally "spice measure" — is the smallest of the four standardised Swedish kitchen measures, defined as exactly 1 ml. It is a Nordic speciality with no direct equivalent in English-speaking kitchens, where the smallest common measure is a quarter teaspoon at about 1.2 ml. Recipes in English handle small quantities with fractions of a teaspoon or with the deliberately vague pinch and dash; the Nordic system gives them a named unit with an exact volume instead. Five kryddmått make a tesked and fifteen make a matsked. Its existence is a small but real advantage in recipe writing: "2 krm" is unambiguous where "a scant half teaspoon" is not.
The exact factor
The factor is exactly 1, so no arithmetic is required. What the page is actually useful for is the relationships around it: 1 krm is 1 ml, a quarter US teaspoon is about 1.23 ml, and a pinch as sometimes formalised in American measuring sets is 1/16 teaspoon, about 0.31 ml. So one kryddmått is roughly three formalised pinches, or a slightly generous quarter teaspoon.
Where you meet this conversion
Strong spices and additives in Nordic recipes: saffron, cardamom, cayenne, ground cloves, salt in small doses, and baking ammonia. Swedish measuring spoon sets always include one, usually as the smallest spoon in the row. The unit is also common in older Swedish recipes for medicinal preparations and preserves. For anyone converting a Swedish recipe into English, the honest translation is to give the millilitre figure directly rather than to attempt a teaspoon fraction, since 1 ml has no clean equivalent in the American set.