diff --git a/htdocs/core/class/unitsTools.class.php b/htdocs/core/class/unitsTools.class.php
new file mode 100644
index 00000000000..79ffdb82338
--- /dev/null
+++ b/htdocs/core/class/unitsTools.class.php
@@ -0,0 +1,119 @@
+<?php
+
+class UnitsTools
+{
+
+	/**
+	 * Get unit from code
+	 * @param string $code code of unit
+	 * @param string $mode 0= id , short_label=Use short label as value, code=use code
+	 * @return int            <0 if KO, Id of code if OK
+	 */
+	static public function getUnitFromCode($code, $mode = 'code')
+	{
+		global $db;
+
+		if($mode == 'short_label'){
+			return dol_getIdFromCode($db, $code, 'c_units', 'short_label', 'rowid');
+		}
+		elseif($mode == 'code'){
+			return dol_getIdFromCode($db, $code, 'c_units', 'code', 'rowid');
+		}
+
+		return $code;
+	}
+
+	/**
+	 * Unit converter
+	 * @param double $value value to convert
+	 * @param int $fk_unit current unit id of value
+	 * @param int $fk_new_unit the id of unit to convert in
+	 * @return double
+	 */
+	static public function unitConverter($value, $fk_unit, $fk_new_unit = 0)
+	{
+		global $db;
+
+		$value  = doubleval(price2num($value));
+		$fk_unit = intval($fk_unit);
+
+		// Calcul en unité de base
+		$scaleUnitPow = self::scaleOfUnitPow($fk_unit);
+
+		// convert to standard unit
+		$value  = $value * $scaleUnitPow;
+		if($fk_new_unit !=0 ){
+			// Calcul en unité de base
+			$scaleUnitPow = self::scaleOfUnitPow($fk_new_unit);
+			if(!empty($scaleUnitPow))
+			{
+				// convert to new unit
+				$value  = $value / $scaleUnitPow;
+			}
+		}
+		return round($value, 2);
+	}
+
+
+
+	/**
+	 * get scale of unit factor
+	 * @param $id int id of unit in dictionary
+	 * @return float|int
+	 */
+	static public function scaleOfUnitPow($id)
+	{
+		$base = 10;
+		// TODO : add base col into unit dictionary table
+		$unit = self::dbGetRow('SELECT scale, unit_type from '.MAIN_DB_PREFIX.'c_units WHERE rowid = '.intval($id));
+		if($unit){
+			// TODO : if base exist in unit dictionary table remove this convertion exception and update convertion infos in database exemple time hour currently scale 3600 will become scale 2 base 60
+			if($unit->unit_type == 'time'){
+				return doubleval($unit->scale);
+			}
+
+			return pow($base, doubleval($unit->scale));
+		}
+
+		return 0;
+	}
+
+	/**
+	 * return first result from query
+	 * @param string $sql the sql query string
+	 * @return bool| var
+	 */
+	static public function dbGetvalue($sql)
+	{
+		global $db;
+		$sql .= ' LIMIT 1;';
+
+		$res = $db->query($sql);
+		if ($res)
+		{
+			$Tresult = $db->fetch_row($res);
+			return $Tresult[0];
+		}
+
+		return false;
+	}
+
+	/**
+	 * return first result from query
+	 * @param string $sql the sql query string
+	 * @return bool| var
+	 */
+	static public function dbGetRow($sql)
+	{
+		global $db;
+		$sql .= ' LIMIT 1;';
+
+		$res = $db->query($sql);
+		if ($res)
+		{
+			return $db->fetch_object($res);
+		}
+
+		return false;
+	}
+}