diff --git a/DrinkingBar.java b/DrinkingBar.java
index a7ccc28..5230ff0 100644
--- a/DrinkingBar.java
+++ b/DrinkingBar.java
@@ -19,7 +19,10 @@ public class DrinkingBar {
    private static final int MINUTES_BEFORE_PAUSE = 4 * MINS_PER_HOUR + MINS_PER_HALF_HOUR;
    private static final int MINUTES_WITH_PAUSE = 6 * MINS_PER_HOUR;
    private static final int DEFAULT_TOTAL_TIME = 8 * MINS_PER_HOUR + MINS_PER_HALF_HOUR;
-   private static final DecimalFormat LITER_FORMAT = new DecimalFormat("0.00");
+   private static final BigDecimal DEFAULT_TOTAL_TIME_BD = BigDecimal.valueOf(DEFAULT_TOTAL_TIME);
+   private static final BigDecimal DEFAULT_TOTAL_LITRES = BigDecimal.valueOf(2.0);
+   private static final BigDecimal QUARTER_LITRE = BigDecimal.valueOf(0.25);
+   private static final DecimalFormat LITRE_FORMAT = new DecimalFormat("0.00");
    private static final DecimalFormat PERCENTAGE_FORMAT = new DecimalFormat("00.00");
    private static final BigDecimal MINS_PER_HOUR_BD = BigDecimal.valueOf(MINS_PER_HOUR);
    private static final MathContext MC_INTEGER = new MathContext(1, RoundingMode.HALF_EVEN);
@@ -28,6 +31,7 @@ public class DrinkingBar {
    private LocalTime endTime;
    private long totalMinutes;
    private BigDecimal totalMinutesBD;
+   private BigDecimal totalLitres;
 
 
    private DrinkingBar(LocalTime startTime) {
@@ -35,6 +39,7 @@ public class DrinkingBar {
       this.totalMinutes = DEFAULT_TOTAL_TIME;
       this.totalMinutesBD = BigDecimal.valueOf(totalMinutes);
       this.endTime = startTime.plusMinutes(totalMinutes);
+      this.totalLitres = DEFAULT_TOTAL_LITRES;
    }
 
 
@@ -57,15 +62,36 @@ public class DrinkingBar {
    }
 
 
+   protected long getPassedMinutes() {
+      return startTime.until(LocalTime.now().truncatedTo(ChronoUnit.MINUTES), ChronoUnit.MINUTES);
+   }
+
+
    private void setEndTime(LocalTime endTime) {
       this.endTime = endTime;
       this.totalMinutes = startTime.until(endTime, ChronoUnit.MINUTES);
       this.totalMinutesBD = BigDecimal.valueOf(totalMinutes);
+      extraInitEndTimeTotalMinutes();
+   }
+
+
+   protected void extraInitEndTimeTotalMinutes() {
+      // correct necessary litres to drink based on the end time.
+      // lower the volume in quarter litre steps
+      BigDecimal calcTotalLitres = DEFAULT_TOTAL_LITRES;
+      BigDecimal totalLitresFromMinutes = DEFAULT_TOTAL_LITRES
+         .multiply(totalMinutesBD) // reverse dreisatz
+         .divide(DEFAULT_TOTAL_TIME_BD, MathContext.DECIMAL64);
+      do {
+         calcTotalLitres = calcTotalLitres.subtract(QUARTER_LITRE);
+      } while (calcTotalLitres.compareTo(totalLitresFromMinutes) >= 0);
+      // add quarter since we always did a step "too many", due to the do ... while loop
+      this.totalLitres = calcTotalLitres.add(QUARTER_LITRE);
    }
 
 
    private void showLoadingBar() {
-      long passedMinutes = startTime.until(LocalTime.now().truncatedTo(ChronoUnit.MINUTES), ChronoUnit.MINUTES);
+      long passedMinutes = getPassedMinutes();
       // long passedMinutes = 0; // DEBUG
       if (passedMinutes > totalMinutes) {
          passedMinutes = totalMinutes;
@@ -84,28 +110,34 @@ public class DrinkingBar {
 
 
    private String fillLoadingBar(long passedMinutes, boolean progressive) {
-      long effectivePassedMinutes = passedMinutes;
-      if (passedMinutes > MINUTES_BEFORE_PAUSE && passedMinutes <= MINUTES_WITH_PAUSE) {
+      long effectivePassedMinutes = passedMinutes < 0 ? 0 : passedMinutes;
+      if (totalMinutes > MINUTES_WITH_PAUSE && passedMinutes > MINUTES_BEFORE_PAUSE && passedMinutes <= MINUTES_WITH_PAUSE) {
          effectivePassedMinutes = MINUTES_BEFORE_PAUSE;
       }
-      double currentLitres = 2.0 / totalMinutes * effectivePassedMinutes + 0.25;
-      double printedLitres = currentLitres - (currentLitres % 0.25);
-      // double currentProgressToNextStep = 100 / 0.25 * (currentLitres - printedLitres);
+      var effectivePassedMinutesBD = BigDecimal.valueOf(effectivePassedMinutes);
+      BigDecimal currentLitres = totalLitres
+         .multiply(effectivePassedMinutesBD) // reverse dreisatz
+         .divide(totalMinutesBD, MathContext.DECIMAL64)
+         .add(QUARTER_LITRE);
+      BigDecimal printedLitres = currentLitres.subtract(currentLitres.remainder(QUARTER_LITRE, MathContext.DECIMAL64));
+      /* BigDecimal currentProgressToNextStep = ONE_HUNDRED_PERCENT
+         .multiply(currentLitres.subtract(printedLitres)) // reverse dreisatz
+         .divide(QUARTER_LITRE, MathContext.DECIMAL64); */
       BigDecimal minutesToNextStep = getMinutesToNextStep(currentLitres);
       String progressivePart = progressive ? "\r" : "";
-      return progressivePart + "Aktuelles Volumen: " + LITER_FORMAT.format(printedLitres) + "L - "
+      return progressivePart + "Aktuelles Volumen: " + LITRE_FORMAT.format(printedLitres) + "L - "
          // + PERCENTAGE_FORMAT.format(currentProgressToNextStep) + "% - "
          + minutesToTimeString(minutesToNextStep);
    }
 
 
-   private BigDecimal getMinutesToNextStep(double currentLitres) {
+   private BigDecimal getMinutesToNextStep(BigDecimal currentLitres) {
       // berechne Liter benötigt bis zum nächsten 0.25er Schritt
-      double litresToNextStep = 0.25 - (currentLitres % 0.25);
+      BigDecimal litresToNextStep = QUARTER_LITRE.subtract(currentLitres.remainder(QUARTER_LITRE));
       // berechne Minuten benötigt für 1 Liter
-      double minutesPerLitre = totalMinutes / 2.0;
+      BigDecimal minutesPerLitre = totalMinutesBD.divide(totalLitres, MathContext.DECIMAL64);
       // berechne Minuten benötigt bis zum nächsten 0.25er Schritt
-      return BigDecimal.valueOf((minutesPerLitre * litresToNextStep) + 1);
+      return minutesPerLitre.multiply(litresToNextStep).setScale(0, RoundingMode.HALF_EVEN);
    }
 
 
diff --git a/LoadingBar.java b/LoadingBar.java
index 5bce1fe..2b79486 100644
--- a/LoadingBar.java
+++ b/LoadingBar.java
@@ -77,13 +77,6 @@ public class LoadingBar {
    }
 
 
-   private void setEndTime(LocalTime endTime) {
-      this.endTime = endTime;
-      this.totalMinutes = startTime.until(endTime, ChronoUnit.MINUTES);
-      this.totalMinutesBD = BigDecimal.valueOf(totalMinutes);
-   }
-
-
    public static void main(String[] args) throws IOException {
       if (args.length == 0) {
          askParametersAndRun();
@@ -330,6 +323,19 @@ public class LoadingBar {
    }
 
 
+   protected long getPassedMinutes() {
+      return startTime.until(LocalTime.now().truncatedTo(ChronoUnit.MINUTES), ChronoUnit.MINUTES);
+   }
+
+
+   private void setEndTime(LocalTime endTime) {
+      this.endTime = endTime;
+      this.totalMinutes = startTime.until(endTime, ChronoUnit.MINUTES);
+      this.totalMinutesBD = BigDecimal.valueOf(totalMinutes);
+   }
+
+
+
    private boolean hasMittagspauseArrived() {
       return startTime.until(LocalTime.now(), ChronoUnit.MINUTES) < DEFAULT_NUMBER_WORK_MINS_BEFORE_LUNCH;
    }
@@ -393,8 +399,7 @@ public class LoadingBar {
          return MIN_LUNCH_DURATION;
       }
       long totalDuration = MAX_NUMBER_WORK_MINS + endTimeOffset;
-      long effectiveLunchDuration = totalDuration - MAX_NUMBER_WORK_MINS_WITHOUT_LUNCH;
-      return getMinLunchDuration(effectiveLunchDuration);
+      return getMinLunchDuration(totalDuration);
    }
 
 
@@ -403,12 +408,12 @@ public class LoadingBar {
          return MIN_LUNCH_DURATION;
       }
       long totalDuration = startTime.until(manualEndTime, ChronoUnit.MINUTES);
-      long effectiveLunchDuration = totalDuration - MAX_NUMBER_WORK_MINS_WITHOUT_LUNCH;
-      return getMinLunchDuration(effectiveLunchDuration);
+      return getMinLunchDuration(totalDuration);
    }
 
 
-   private long getMinLunchDuration(long effectiveLunchDuration) {
+   private long getMinLunchDuration(long precalculatedTotalDuration) {
+      long effectiveLunchDuration = precalculatedTotalDuration - MAX_NUMBER_WORK_MINS_WITHOUT_LUNCH;
       if (effectiveLunchDuration < 0) {
          effectiveLunchDuration = 0;
       }
@@ -431,7 +436,7 @@ public class LoadingBar {
 
 
    private void showLoadingBar() {
-      long passedMinutes = startTime.until(LocalTime.now().truncatedTo(ChronoUnit.MINUTES), ChronoUnit.MINUTES);
+      long passedMinutes = getPassedMinutes();
       // long passedMinutes = 0; // DEBUG
       if (passedMinutes > totalMinutes) {
          passedMinutes = totalMinutes;
diff --git a/SimpleLoadingBar.java b/SimpleLoadingBar.java
index 927932d..90bea03 100644
--- a/SimpleLoadingBar.java
+++ b/SimpleLoadingBar.java
@@ -112,6 +112,11 @@ public class SimpleLoadingBar {
    }
 
 
+   protected long getPassedMinutes() {
+      return startTime.until(LocalTime.now().truncatedTo(ChronoUnit.MINUTES), ChronoUnit.MINUTES);
+   }
+
+
    private void setEndTime(LocalTime endTime) {
       this.endTime = endTime;
       this.totalMinutes = startTime.until(endTime, ChronoUnit.MINUTES);
@@ -128,7 +133,7 @@ public class SimpleLoadingBar {
 
 
    private void showLoadingBar() {
-      long passedMinutes = startTime.until(LocalTime.now().truncatedTo(ChronoUnit.MINUTES), ChronoUnit.MINUTES);
+      long passedMinutes = getPassedMinutes();
       // long passedMinutes = 0; // DEBUG
       if (passedMinutes > totalMinutes) {
          passedMinutes = totalMinutes;