Calculate the an adidas size code by using real life sizes from different regions

adidas-size-code-calculator.js

function calculateSizeCode(size, type){
    switch(type){
        case 'USM':
            return size * 20 + 530 - 80;
            break;
        case 'USF':
            return size * 20 + 530 - 100;
            break;
        case 'UK':
            return size * 20 + 530 - 70;
            break;
        case 'EU':
            const calc = size * 15 + 530 - 36 * 15;
            if(calc / 10 % 1 === 0){
                return calc;
            }
            return ((calc + 0.5) / 10 % 1 !== 0 ? calc - 0.5 : calc + 0.5);
            break;
    }
}
function calculateSize(sizeCode, type){
    switch(type){
        case 'USM':
            return 4 + (sizeCode - 530) / 20;
			break;
		case 'USF':
			return 5 + (sizeCode - 530) / 20;
			break;
		case 'UK':
			return 3.5 + (sizeCode - 530) / 20;
			break;
		case 'EU':
			return Math.round((36 + (sizeCode - 530) * 2 / 30) * 10) / 10;
			break;
	}
}

/* example: calculateSizeCode(11,   'USM')  = 670
            calculateSizeCode(39.3, 'EU')   = 580
            calculateSizeCode(40,   'EU')   = 590
            calculateSizeCode(44.7, 'EU')   = 660
            calculateSizeCode(10.5, 'UK')   = 670
            calculateSizeCode(39.5, 'EU')   = 582 (not a valid size code, size 39.5 does not exist)
            calculateSizeCode(10.2, 'UK')   = 664 (not a valid size code, size 10.2 does not exist) */