diff --git a/CHANGELOG.md b/CHANGELOG.md
index 705dd118..c706be1c 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -8,7 +8,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 See [Release](https://github.com/itsallcode/white-rabbit/releases/tag/v1.10.0) / [Milestone](https://github.com/itsallcode/white-rabbit/milestone/12?closed=1)
 
-## [1.9.0] - 2022-??-??
+## [1.9.0] - 2024-??-??
 
 See [Release](https://github.com/itsallcode/white-rabbit/releases/tag/v1.9.0) / [Milestone](https://github.com/itsallcode/white-rabbit/milestone/11?closed=1)
 
@@ -22,7 +22,8 @@ This release requires Java 21.
 
 ### New Features
 
-* [#273](https://github.com/itsallcode/white-rabbit/pull/273): Added buttons to monthly report for jumping to the previous/next month
+* [#273](https://github.com/itsallcode/white-rabbit/pull/273): Added buttons to monthly report for jumping to the previous/next month.
+* [#276](https://github.com/itsallcode/white-rabbit/pull/276): Added config option `reduce_mandatory_break_by_interruption`.
 
 ### Bugfixes
 
diff --git a/docs/user_guide.md b/docs/user_guide.md
index 99b1d714..02a80a9e 100644
--- a/docs/user_guide.md
+++ b/docs/user_guide.md
@@ -69,10 +69,12 @@ Restart WhiteRabbit after changing the configuration file.
   * We recommend to configure this when starting to use WhiteRabbit.
 * `mandatory_break`: mandatory break per day (default: 45 minutes). Format: see [below](#duration-format). Caution: This setting will also affect the past, i.e. the overtime of **all** days will be re-calculated.
   * We recommend to configure this when starting to use WhiteRabbit.
+* `reduce_mandatory_break_by_interruption`: Reduce the mandatory break by entered interruption (`true` or `false`, default: `false`). If this is `true`, the mandatory break will be set to zero when the interruption is longer than the mandatory break.
+  * We recommend to configure this when starting to use WhiteRabbit.
 
 #### Duration format
 
-Enter duration values in the format used by [Duration.parse()](https://docs.oracle.com/en/java/javase/11/docs/api/java.base/java/time/Duration.html#parse(java.lang.CharSequence)). Examples:
+Enter duration values in the format used by [Duration.parse()](https://docs.oracle.com/en/java/javase/21/docs/api/java.base/java/time/Duration.html#parse(java.lang.CharSequence)). Examples:
 
 * `PT5H`: 5 hours
 * `PT5H30M`: 5 hours and 30 minutes
@@ -221,4 +223,4 @@ The default values are:
 csv.destination = $HOME
 csv.separator = ","
 csv.filter_for_weekdays = False
-```
\ No newline at end of file
+```
diff --git a/logic/src/main/java/org/itsallcode/whiterabbit/logic/Config.java b/logic/src/main/java/org/itsallcode/whiterabbit/logic/Config.java
index a1f165a8..d6aefb1a 100644
--- a/logic/src/main/java/org/itsallcode/whiterabbit/logic/Config.java
+++ b/logic/src/main/java/org/itsallcode/whiterabbit/logic/Config.java
@@ -21,6 +21,8 @@ public interface Config
 
     Optional<Duration> getMandatoryBreak();
 
+    boolean reduceMandatoryBreakByInterruption();
+
     default Path getProjectFile()
     {
         return getDataDir().resolve(PROJECTS_JSON);
diff --git a/logic/src/main/java/org/itsallcode/whiterabbit/logic/ConfigFile.java b/logic/src/main/java/org/itsallcode/whiterabbit/logic/ConfigFile.java
index f7ae5968..fb4f577e 100644
--- a/logic/src/main/java/org/itsallcode/whiterabbit/logic/ConfigFile.java
+++ b/logic/src/main/java/org/itsallcode/whiterabbit/logic/ConfigFile.java
@@ -79,6 +79,12 @@ public Optional<Duration> getMandatoryBreak()
         return getOptionalValue("mandatory_break").map(Duration::parse);
     }
 
+    @Override
+    public boolean reduceMandatoryBreakByInterruption()
+    {
+        return getOptionalValue("reduce_mandatory_break_by_interruption").map(Boolean::valueOf).orElse(false);
+    }
+
     @Override
     public boolean allowMultipleInstances()
     {
diff --git a/logic/src/main/java/org/itsallcode/whiterabbit/logic/service/contract/ContractTermsService.java b/logic/src/main/java/org/itsallcode/whiterabbit/logic/service/contract/ContractTermsService.java
index b48477f2..37ea733d 100644
--- a/logic/src/main/java/org/itsallcode/whiterabbit/logic/service/contract/ContractTermsService.java
+++ b/logic/src/main/java/org/itsallcode/whiterabbit/logic/service/contract/ContractTermsService.java
@@ -18,7 +18,6 @@ public ContractTermsService(final Config config)
         this.config = config;
     }
 
-
     public Duration getMandatoryBreak(final DayRecord day)
     {
         if (!day.getType().isWorkDay())
@@ -28,7 +27,15 @@ public Duration getMandatoryBreak(final DayRecord day)
         final Duration workingTime = day.getRawWorkingTime().minus(day.getInterruption());
         if (workingTime.compareTo(MIN_WORKING_TIME_WITHOUT_BREAK) > 0)
         {
-            return getMandatoryBreak();
+            Duration mandatoryBreak = getMandatoryBreak();
+            if (config.reduceMandatoryBreakByInterruption())
+            {
+                mandatoryBreak = mandatoryBreak.minus(day.getInterruption());
+            }
+            if (mandatoryBreak.isPositive())
+            {
+                return mandatoryBreak;
+            }
         }
         return Duration.ZERO;
     }
diff --git a/logic/src/test/java/org/itsallcode/whiterabbit/logic/ConfigFileTest.java b/logic/src/test/java/org/itsallcode/whiterabbit/logic/ConfigFileTest.java
index b1a94519..fcdfc860 100644
--- a/logic/src/test/java/org/itsallcode/whiterabbit/logic/ConfigFileTest.java
+++ b/logic/src/test/java/org/itsallcode/whiterabbit/logic/ConfigFileTest.java
@@ -114,6 +114,27 @@ void getMandatoryBreak_returnsCustomValue()
         assertThat(configFile.getMandatoryBreak()).isPresent().hasValue(Duration.ofMinutes(0));
     }
 
+    @Test
+    void reduceMandatoryBreakByInterruption_returnsDefault()
+    {
+        when(propertiesMock.getProperty("reduce_mandatory_break_by_interruption")).thenReturn(null);
+        assertThat(configFile.reduceMandatoryBreakByInterruption()).isFalse();
+    }
+
+    @Test
+    void reduceMandatoryBreakByInterruption_returnsCustomValue()
+    {
+        when(propertiesMock.getProperty("reduce_mandatory_break_by_interruption")).thenReturn("true");
+        assertThat(configFile.reduceMandatoryBreakByInterruption()).isTrue();
+    }
+
+    @Test
+    void reduceMandatoryBreakByInterruption_invalidValue()
+    {
+        when(propertiesMock.getProperty("reduce_mandatory_break_by_interruption")).thenReturn("invalid");
+        assertThat(configFile.reduceMandatoryBreakByInterruption()).isFalse();
+    }
+
     @Test
     void getLocale_returnsDefault()
     {
diff --git a/logic/src/test/java/org/itsallcode/whiterabbit/logic/ConfigTest.java b/logic/src/test/java/org/itsallcode/whiterabbit/logic/ConfigTest.java
index 19ec2fad..cd1b21b4 100644
--- a/logic/src/test/java/org/itsallcode/whiterabbit/logic/ConfigTest.java
+++ b/logic/src/test/java/org/itsallcode/whiterabbit/logic/ConfigTest.java
@@ -59,6 +59,12 @@ public Optional<Duration> getMandatoryBreak()
             return Optional.empty();
         }
 
+        @Override
+        public boolean reduceMandatoryBreakByInterruption()
+        {
+            return false;
+        }
+
         @Override
         public boolean allowMultipleInstances()
         {
diff --git a/logic/src/test/java/org/itsallcode/whiterabbit/logic/model/DayRecordTest.java b/logic/src/test/java/org/itsallcode/whiterabbit/logic/model/DayRecordTest.java
index 631793f2..78f9d7a8 100644
--- a/logic/src/test/java/org/itsallcode/whiterabbit/logic/model/DayRecordTest.java
+++ b/logic/src/test/java/org/itsallcode/whiterabbit/logic/model/DayRecordTest.java
@@ -16,6 +16,8 @@
 import org.itsallcode.whiterabbit.logic.service.project.ProjectService;
 import org.itsallcode.whiterabbit.logic.storage.data.JsonModelFactory;
 import org.itsallcode.whiterabbit.logic.test.TestingConfig;
+import org.itsallcode.whiterabbit.logic.test.TestingConfig.Builder;
+import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.extension.ExtendWith;
 import org.mockito.Mock;
@@ -27,6 +29,13 @@ class DayRecordTest
     @Mock
     private ProjectService projectServiceMock;
     private final ModelFactory modelFactory = new JsonModelFactory();
+    private Builder configBuilder;
+
+    @BeforeEach
+    void createDefaultConfig()
+    {
+        configBuilder = TestingConfig.builder();
+    }
 
     @Test
     void mandatoryWorkingTimeIsZeroOnWeekend()
@@ -119,6 +128,30 @@ void testMandatoryBreakConsidersInterruptionLessThan6hours()
                 Duration.ZERO);
     }
 
+    @Test
+    void testMandatoryBreakReducedByInterruption()
+    {
+        configBuilder.withReduceMandatoryBreakByInterruption(true);
+        assertMandatoryBreak(LocalDate.of(2018, 10, 1), LocalTime.of(8, 0), LocalTime.of(18, 0), Duration.ofMinutes(10),
+                Duration.ofMinutes(35));
+    }
+
+    @Test
+    void testMandatoryBreakNotReducedByInterruptionWhenWorkingLessThan6h()
+    {
+        configBuilder.withReduceMandatoryBreakByInterruption(true);
+        assertMandatoryBreak(LocalDate.of(2018, 10, 1), LocalTime.of(8, 0), LocalTime.of(13, 0), Duration.ofMinutes(10),
+                Duration.ZERO);
+    }
+
+    @Test
+    void testMandatoryBreakZeroForLongerInterruption()
+    {
+        configBuilder.withReduceMandatoryBreakByInterruption(true);
+        assertMandatoryBreak(LocalDate.of(2018, 10, 1), LocalTime.of(8, 0), LocalTime.of(18, 0), Duration.ofMinutes(50),
+                Duration.ZERO);
+    }
+
     @Test
     void testWorkingTime1h()
     {
@@ -507,17 +540,17 @@ void dayWithActivitiesListIsNonDummy()
         assertNonDummyDay(day);
     }
 
-    private void assertDummyDay(DayRecord day)
+    private void assertDummyDay(final DayRecord day)
     {
         assertThat(day.isDummyDay()).as("dummy").isTrue();
     }
 
-    private void assertNonDummyDay(DayRecord day)
+    private void assertNonDummyDay(final DayRecord day)
     {
         assertThat(day.isDummyDay()).as("dummy").isFalse();
     }
 
-    private MonthIndex month(LocalDate date, Duration overtimePreviousMonth, DayData... days)
+    private MonthIndex month(final LocalDate date, final Duration overtimePreviousMonth, final DayData... days)
     {
         final MonthData jsonMonth = modelFactory.createMonthData();
         jsonMonth.setDays(asList(days));
@@ -527,59 +560,63 @@ private MonthIndex month(LocalDate date, Duration overtimePreviousMonth, DayData
         return MonthIndex.create(contractTerms(), projectServiceMock, modelFactory, jsonMonth);
     }
 
-    private void assertOvertime(LocalDate date, LocalTime begin, LocalTime end, Duration expectedOvertime)
+    private void assertOvertime(final LocalDate date, final LocalTime begin, final LocalTime end,
+            final Duration expectedOvertime)
     {
         final DayRecord day = createDay(date, begin, end, null, null);
         assertThat(day.getOvertime()).as("overtime").isEqualTo(expectedOvertime);
     }
 
-    private void assertMandatoryBreak(LocalDate date, LocalTime begin, LocalTime end, Duration expectedDuration)
+    private void assertMandatoryBreak(final LocalDate date, final LocalTime begin, final LocalTime end,
+            final Duration expectedDuration)
     {
         assertMandatoryBreak(date, begin, end, Duration.ZERO, expectedDuration);
     }
 
-    private void assertMandatoryBreak(LocalDate date, LocalTime begin, LocalTime end, Duration interruption,
-            Duration expectedDuration)
+    private void assertMandatoryBreak(final LocalDate date, final LocalTime begin, final LocalTime end,
+            final Duration interruption,
+            final Duration expectedDuration)
     {
         assertThat(getMandatoryBreak(date, begin, end, interruption)).as("mandatory break").isEqualTo(expectedDuration);
     }
 
-    private void assertMandatoryWorkingTime(LocalDate date, LocalTime begin, LocalTime end,
-            Duration expectedMandatoryWorkingTime)
+    private void assertMandatoryWorkingTime(final LocalDate date, final LocalTime begin, final LocalTime end,
+            final Duration expectedMandatoryWorkingTime)
     {
         assertThat(getMandatoryWorkingTime(date, begin, end)).as("mandatory working time")
                 .isEqualTo(expectedMandatoryWorkingTime);
     }
 
-    private Duration getMandatoryWorkingTime(LocalDate date, LocalTime begin, LocalTime end)
+    private Duration getMandatoryWorkingTime(final LocalDate date, final LocalTime begin, final LocalTime end)
     {
         final DayRecord day = createDay(date, begin, end, null, null);
         return day.getMandatoryWorkingTime();
     }
 
-    private Duration getMandatoryBreak(LocalDate date, LocalTime begin, LocalTime end, Duration interruption)
+    private Duration getMandatoryBreak(final LocalDate date, final LocalTime begin, final LocalTime end,
+            final Duration interruption)
     {
         final DayRecord day = createDay(date, begin, end, null, interruption);
         return day.getMandatoryBreak();
     }
 
-    private void assertWorkingDay(LocalDate date, boolean expected)
+    private void assertWorkingDay(final LocalDate date, final boolean expected)
     {
         assertThat(createDay(date).getType().isWorkDay()).isEqualTo(expected);
     }
 
-    private void assertType(LocalDate date, DayType expected)
+    private void assertType(final LocalDate date, final DayType expected)
     {
         final DayRecord day = createDay(date);
         assertDayType(day, expected);
     }
 
-    private void assertDayType(DayRecord day, DayType expected)
+    private void assertDayType(final DayRecord day, final DayType expected)
     {
         assertThat(day.getType()).isEqualTo(expected);
     }
 
-    private DayRecord createDay(LocalDate date)
+    private DayRecord createDay(final LocalDate date)
     {
         return createDay(date, null, null);
     }
@@ -589,29 +626,32 @@ private DayRecord createDummyDay()
         return createDummyDay(LocalDate.of(2021, 7, 20));
     }
 
-    private DayRecord createDummyDay(LocalDate date)
+    private DayRecord createDummyDay(final LocalDate date)
     {
         return createDay(date);
     }
 
-    private DayRecord createDay(LocalDate date, LocalTime begin, LocalTime end)
+    private DayRecord createDay(final LocalDate date, final LocalTime begin, final LocalTime end)
     {
         return createDay(date, begin, end, null, null);
     }
 
-    private DayRecord createDay(LocalDate date, LocalTime begin, LocalTime end, DayType type, Duration interruption)
+    private DayRecord createDay(final LocalDate date, final LocalTime begin, final LocalTime end, final DayType type,
+            final Duration interruption)
     {
         return createDay(date, begin, end, type, interruption, null);
     }
 
-    private DayRecord createDay(LocalDate date, LocalTime begin, LocalTime end, DayType type, Duration interruption,
-            DayRecord previousDay)
+    private DayRecord createDay(final LocalDate date, final LocalTime begin, final LocalTime end, final DayType type,
+            final Duration interruption,
+            final DayRecord previousDay)
     {
         return createDay(date, begin, end, type, interruption, previousDay, null);
     }
 
-    private DayRecord createDay(LocalDate date, LocalTime begin, LocalTime end, DayType type, Duration interruption,
-            DayRecord previousDay, MonthIndex month)
+    private DayRecord createDay(final LocalDate date, final LocalTime begin, final LocalTime end, final DayType type,
+            final Duration interruption,
+            final DayRecord previousDay, final MonthIndex month)
     {
         final DayData day = modelFactory.createDayData();
         day.setBegin(begin);
@@ -628,7 +668,7 @@ private DayRecord createDay(final DayData DayData)
         return new DayRecord(null, DayData, null, null, projectServiceMock, modelFactory);
     }
 
-    private DayRecord dayRecord(DayData day, DayRecord previousDay, MonthIndex month)
+    private DayRecord dayRecord(final DayData day, final DayRecord previousDay, final MonthIndex month)
     {
         final ContractTermsService contractTerms = contractTerms();
         return new DayRecord(contractTerms, day, previousDay, month, projectServiceMock, modelFactory);
@@ -636,6 +676,6 @@ private DayRecord dayRecord(DayData day, DayRecord previousDay, MonthIndex month
 
     private ContractTermsService contractTerms()
     {
-        return new ContractTermsService(TestingConfig.builder().build());
+        return new ContractTermsService(configBuilder.build());
     }
 }
diff --git a/logic/src/test/java/org/itsallcode/whiterabbit/logic/test/TestingConfig.java b/logic/src/test/java/org/itsallcode/whiterabbit/logic/test/TestingConfig.java
index e2d82daa..c2f6f459 100644
--- a/logic/src/test/java/org/itsallcode/whiterabbit/logic/test/TestingConfig.java
+++ b/logic/src/test/java/org/itsallcode/whiterabbit/logic/test/TestingConfig.java
@@ -13,6 +13,7 @@ public class TestingConfig implements Config
     private final Locale locale;
     private final Duration currentHoursPerDay;
     private final Duration mandatoryBreak;
+    private final boolean reduceMandatoryBreakByInterruption;
 
     private TestingConfig(final Builder builder)
     {
@@ -20,6 +21,7 @@ private TestingConfig(final Builder builder)
         this.locale = builder.locale;
         this.currentHoursPerDay = builder.currentHoursPerDay;
         this.mandatoryBreak = builder.mandatoryBreak;
+        this.reduceMandatoryBreakByInterruption = builder.reduceMandatoryBreakByInterruption;
     }
 
     @Override
@@ -46,6 +48,12 @@ public Optional<Duration> getMandatoryBreak()
         return Optional.ofNullable(mandatoryBreak);
     }
 
+    @Override
+    public boolean reduceMandatoryBreakByInterruption()
+    {
+        return reduceMandatoryBreakByInterruption;
+    }
+
     @Override
     public boolean allowMultipleInstances()
     {
@@ -77,7 +85,8 @@ public static Builder builder()
 
     public static final class Builder
     {
-        public Duration mandatoryBreak;
+        private boolean reduceMandatoryBreakByInterruption = false;
+        private Duration mandatoryBreak;
         private Path dataDir;
         private Locale locale;
         private Duration currentHoursPerDay;
@@ -110,6 +119,12 @@ public Builder withMandatoryBreak(final Duration mandatoryBreak)
             return this;
         }
 
+        public Builder withReduceMandatoryBreakByInterruption(final boolean reduceMandatoryBreakByInterruption)
+        {
+            this.reduceMandatoryBreakByInterruption = reduceMandatoryBreakByInterruption;
+            return this;
+        }
+
         public TestingConfig build()
         {
             return new TestingConfig(this);