diff --git a/bundles/org.openhab.core/src/main/java/org/openhab/core/library/types/DecimalType.java b/bundles/org.openhab.core/src/main/java/org/openhab/core/library/types/DecimalType.java
index 137a0f15006..ea704281217 100644
--- a/bundles/org.openhab.core/src/main/java/org/openhab/core/library/types/DecimalType.java
+++ b/bundles/org.openhab.core/src/main/java/org/openhab/core/library/types/DecimalType.java
@@ -82,7 +82,7 @@ public DecimalType(String value, Locale locale) {
         DecimalFormat df = (DecimalFormat) NumberFormat.getInstance(locale);
         df.setParseBigDecimal(true);
         ParsePosition position = new ParsePosition(0);
-        BigDecimal parsedValue = (BigDecimal) df.parseObject(value, position);
+        BigDecimal parsedValue = (BigDecimal) df.parseObject(value.toUpperCase(locale), position);
         if (parsedValue == null || position.getErrorIndex() != -1 || position.getIndex() < value.length()) {
             throw new NumberFormatException("Invalid BigDecimal value: " + value);
         }
diff --git a/bundles/org.openhab.core/src/main/java/org/openhab/core/library/types/QuantityType.java b/bundles/org.openhab.core/src/main/java/org/openhab/core/library/types/QuantityType.java
index 779bdfcd67e..d7059de031b 100644
--- a/bundles/org.openhab.core/src/main/java/org/openhab/core/library/types/QuantityType.java
+++ b/bundles/org.openhab.core/src/main/java/org/openhab/core/library/types/QuantityType.java
@@ -70,11 +70,11 @@ public class QuantityType<T extends Quantity<T>> extends Number
     public static final QuantityType<Dimensionless> ZERO = new QuantityType<>(0, AbstractUnit.ONE);
     public static final QuantityType<Dimensionless> ONE = new QuantityType<>(1, AbstractUnit.ONE);
 
-    // Regular expression to split unit from value
-    // split on any blank character, even none (\\s*) which occurs after a digit (?<=\\d) and before
-    // a "unit" character ?=[a-zA-Z°µ%'] which itself must not be preceded by plus/minus digit (?![\\+\\-]?\\d).
-    // The later would be an exponent from the scalar value.
-    private static final String UNIT_PATTERN = "(?<=\\d)\\s*(?=[a-zA-Z°µ%'](?![\\+\\-]?\\d))";
+    // Regular expression to split unit from value. Split on any blank character, even none (\\s*)
+    // which occurs after a digit (?<=\\d) and before a "unit" character ?=[a-zA-Z°µ\u03BC%']
+    // which itself must not be preceded by plus/minus digit (?![\\+\\-]?\\d).
+    // The latter would be an exponent from the scalar value.
+    private static final String UNIT_PATTERN = "(?<=\\d)\\s*(?=[a-zA-Z°µ\u03BC%'](?![\\+\\-]?\\d))";
 
     static {
         UnitInitializer.init();
@@ -119,13 +119,16 @@ public QuantityType(String value) {
     public QuantityType(String value, Locale locale) {
         String[] constituents = value.split(UNIT_PATTERN);
 
+        if (constituents.length > 0) {
+            constituents[0] = constituents[0].toUpperCase(locale);
+        }
         // getQuantity needs a space between numeric value and unit
         String formatted = String.join(" ", constituents);
         if (!formatted.contains(" ")) {
             DecimalFormat df = (DecimalFormat) NumberFormat.getInstance(locale);
             df.setParseBigDecimal(true);
             ParsePosition position = new ParsePosition(0);
-            BigDecimal parsedValue = (BigDecimal) df.parseObject(value, position);
+            BigDecimal parsedValue = (BigDecimal) df.parseObject(formatted, position);
             if (parsedValue == null || position.getErrorIndex() != -1 || position.getIndex() < value.length()) {
                 throw new NumberFormatException("Invalid BigDecimal value: " + value);
             }
@@ -294,7 +297,7 @@ public Dimension getDimension() {
      * change the dimension.
      *
      * @param targetUnit the unit to which this {@link QuantityType} will be converted to.
-     * @return the new {@link QuantityType} in the given {@link Unit} or {@code null} in case of an erro.
+     * @return the new {@link QuantityType} in the given {@link Unit} or {@code null} in case of an error.
      */
     public @Nullable QuantityType<?> toInvertibleUnit(Unit<?> targetUnit) {
         // only invert if unit is not equal and inverse is compatible and targetUnit is not ONE
diff --git a/bundles/org.openhab.core/src/test/java/org/openhab/core/library/types/DecimalTypeTest.java b/bundles/org.openhab.core/src/test/java/org/openhab/core/library/types/DecimalTypeTest.java
index 31144649450..1a591ae21c3 100644
--- a/bundles/org.openhab.core/src/test/java/org/openhab/core/library/types/DecimalTypeTest.java
+++ b/bundles/org.openhab.core/src/test/java/org/openhab/core/library/types/DecimalTypeTest.java
@@ -90,6 +90,12 @@ public void testValidConstructors(String value) throws Exception {
         DecimalType.valueOf(value);
     }
 
+    @Test
+    public void testLowerCaseExponents() {
+        assertEquals(DecimalType.valueOf("1e3"), DecimalType.valueOf("1E3"));
+        assertEquals(DecimalType.valueOf("2.5e-3"), DecimalType.valueOf("2.5E-3"));
+    }
+
     @ParameterizedTest
     @MethodSource("locales")
     public void testLocalizedStringConstruction(Locale defaultLocale) {
diff --git a/bundles/org.openhab.core/src/test/java/org/openhab/core/library/types/PercentTypeTest.java b/bundles/org.openhab.core/src/test/java/org/openhab/core/library/types/PercentTypeTest.java
index e9871ac6238..e29066c0873 100644
--- a/bundles/org.openhab.core/src/test/java/org/openhab/core/library/types/PercentTypeTest.java
+++ b/bundles/org.openhab.core/src/test/java/org/openhab/core/library/types/PercentTypeTest.java
@@ -77,6 +77,12 @@ public void testValidConstructors(String value) {
         PercentType.valueOf(value);
     }
 
+    @Test
+    public void testLowerCaseExponents() {
+        assertEquals(PercentType.valueOf("1e2"), PercentType.valueOf("1E2"));
+        assertEquals(PercentType.valueOf("1.1e1"), PercentType.valueOf("1.1E1"));
+    }
+
     @ParameterizedTest
     @MethodSource("locales")
     public void testLocalizedStringConstruction(Locale defaultLocale) {
diff --git a/bundles/org.openhab.core/src/test/java/org/openhab/core/library/types/QuantityTypeTest.java b/bundles/org.openhab.core/src/test/java/org/openhab/core/library/types/QuantityTypeTest.java
index 248a090dec2..e521be9e8c4 100644
--- a/bundles/org.openhab.core/src/test/java/org/openhab/core/library/types/QuantityTypeTest.java
+++ b/bundles/org.openhab.core/src/test/java/org/openhab/core/library/types/QuantityTypeTest.java
@@ -146,6 +146,20 @@ public void testValidConstructors(Locale locale) {
         QuantityType.valueOf("2m");
     }
 
+    @Test
+    public void testLowerCaseExponents() {
+        assertEquals(QuantityType.valueOf("10e3"), QuantityType.valueOf("10E3"));
+        assertEquals(QuantityType.valueOf("1.1e3 W"), QuantityType.valueOf("1.1E3 W"));
+        assertEquals(QuantityType.valueOf("1.1e3 m"), QuantityType.valueOf("1.1E3 m"));
+        assertEquals(QuantityType.valueOf("1.1e3m"), QuantityType.valueOf("1.1E3 m"));
+        assertEquals(QuantityType.valueOf("1.1e3m³"), QuantityType.valueOf("1.1E3 m³"));
+        assertEquals(QuantityType.valueOf("1.1e3m·cm"), QuantityType.valueOf("1.1E3 m·cm"));
+        assertEquals(QuantityType.valueOf("1.1e3 \u03BCm"), QuantityType.valueOf("1.1E3 µm"));
+        assertEquals(QuantityType.valueOf("1.1e3\u03BCm"), QuantityType.valueOf("1.1E3 µm"));
+        assertEquals(QuantityType.valueOf("1.1e3 \u00B5m"), QuantityType.valueOf("1.1E3 µm"));
+        assertEquals(QuantityType.valueOf("1.1e3\u00B5m"), QuantityType.valueOf("1.1E3 µm"));
+    }
+
     @ParameterizedTest
     @MethodSource("locales")
     public void testLocalizedStringConstruction(Locale defaultLocale) {