diff --git a/src/action/AbstractAction.php b/src/action/AbstractAction.php
index 42857d01..84352f41 100755
--- a/src/action/AbstractAction.php
+++ b/src/action/AbstractAction.php
@@ -55,6 +55,8 @@ abstract class AbstractAction implements \JsonSerializable, ActionInterface
     /** @var ActionInterface */
     protected $parent;
 
+    protected float $fractionOfMonth;
+
     /**
      * @param SaleInterface $sale
      * @param ActionInterface $parent
@@ -68,7 +70,8 @@ public function __construct(
         DateTimeImmutable $time,
         SaleInterface $sale = null,
         ActionState $state = null,
-        ActionInterface $parent = null
+        ActionInterface $parent = null,
+        float $fractionOfMonth = 0.0
     ) {
         $this->id       = $id;
         $this->type     = $type;
@@ -79,6 +82,7 @@ public function __construct(
         $this->sale     = $sale;
         $this->state    = $state;
         $this->parent   = $parent;
+        $this->fractionOfMonth = $fractionOfMonth;
     }
 
     /**
@@ -218,6 +222,10 @@ public function setSale(SaleInterface $sale)
         $this->sale = $sale;
     }
 
+    public function getFractionOfMonth(): float
+    {
+        return $this->fractionOfMonth;
+    }
     /**
      * {@inheritdoc}
      */
@@ -232,6 +240,17 @@ public function getUsageInterval(): UsageInterval
             return UsageInterval::wholeMonth($this->getTime());
         }
 
-        return UsageInterval::withinMonth($this->getTime(), $this->getSale()->getTime(), $this->getSale()->getCloseTime());
+        if ($this->getFractionOfMonth() > 0) {
+            return UsageInterval::withMonthAndFraction(
+                $this->getTime(),
+                $this->getSale()->getTime(),
+                $this->getFractionOfMonth()
+            );
+        }
+        return UsageInterval::withinMonth(
+            $this->getTime(),
+            $this->getSale()->getTime(),
+            $this->getSale()->getCloseTime()
+        );
     }
 }
diff --git a/src/action/ActionInterface.php b/src/action/ActionInterface.php
index 4662c1b0..456a120a 100644
--- a/src/action/ActionInterface.php
+++ b/src/action/ActionInterface.php
@@ -82,4 +82,6 @@ public function hasSale();
     public function setSale(SaleInterface $sale);
 
     public function getUsageInterval(): UsageInterval;
+
+    public function getFractionOfMonth(): float;
 }
diff --git a/src/action/UsageInterval.php b/src/action/UsageInterval.php
index 2daabdaf..a1280d9f 100644
--- a/src/action/UsageInterval.php
+++ b/src/action/UsageInterval.php
@@ -82,6 +82,45 @@ public static function withinMonth(
         );
     }
 
+    /**
+     * Calculates the usage interval for the given month for the given start date and fraction of month value.
+     *
+     * @param DateTimeImmutable $month the month to calculate the usage interval for
+     * @param DateTimeImmutable $start the start date of the sale
+     * @param float $fractionOfMonth the fraction of manth
+     * @return static
+     */
+    public static function withMonthAndFraction(
+        DateTimeImmutable $month,
+        DateTimeImmutable $start,
+        float $fractionOfMonth
+    ): self {
+        if ($fractionOfMonth < 0 || $fractionOfMonth > 1) {
+            throw new InvalidArgumentException('Fraction of month must be between 0 and 1');
+        }
+        $month = self::toMonth($month);
+        $nextMonth = $month->modify('+1 month');
+
+        if ($start >= $nextMonth) {
+            $start = $month;
+        }
+
+        $effectiveSince = max($start, $month);
+
+        if ($fractionOfMonth === 1.0) {
+            $effectiveTill = $month->modify('+1 month');
+        } else {
+            $monthDays = (int) $month->format('t');
+            $days = (int) round($monthDays * $fractionOfMonth);
+            $effectiveTill = $effectiveSince->modify(sprintf('+%d days', $days));
+        }
+
+        return new self(
+            $effectiveSince,
+            $effectiveTill,
+        );
+    }
+
     public function start(): DateTimeImmutable
     {
         return $this->start;
diff --git a/tests/behat/bootstrap/FeatureContext.php b/tests/behat/bootstrap/FeatureContext.php
index 3b790c8d..5ecdcc8e 100644
--- a/tests/behat/bootstrap/FeatureContext.php
+++ b/tests/behat/bootstrap/FeatureContext.php
@@ -188,14 +188,27 @@ public function actionIs(string $target, string $type, float $amount, string $un
         $type = Type::anyId($type);
         $target = new Target(Target::ANY, $target);
         $time = new DateTimeImmutable($date);
+        $fractionOfMonth = 1;
         if ($this->sale->getCloseTime() instanceof DateTimeImmutable) {
-            $amount = $amount * $this->getFractionOfMonth(
+            $fractionOfMonth = $this->getFractionOfMonth(
                 $time, $time, $this->sale->getCloseTime()
             );
+            $amount = $amount * $fractionOfMonth;
         }
         $quantity = Quantity::create($unit, $amount);
 
-        $this->action = new Action(null, $type, $target, $quantity, $this->customer, $time);
+        $this->action = new Action(
+            null,
+            $type,
+            $target,
+            $quantity,
+            $this->customer,
+            $time,
+            null,
+            null,
+            null,
+            $fractionOfMonth
+        );
     }
 
     private function getFractionOfMonth(DateTimeImmutable $month, DateTimeImmutable $startTime, DateTimeImmutable $endTime): float
diff --git a/tests/unit/action/UsageIntervalTest.php b/tests/unit/action/UsageIntervalTest.php
index 12282720..4951434c 100644
--- a/tests/unit/action/UsageIntervalTest.php
+++ b/tests/unit/action/UsageIntervalTest.php
@@ -120,4 +120,118 @@ public function provideWithinMonth()
             ]
         ];
     }
+
+    /**
+     * @dataProvider provideWithMonthAndFraction
+     */
+    public function testWithMonthAndFraction(array $constructor, array $expectations): void
+    {
+        $month = new DateTimeImmutable($constructor['month']);
+        $start = new DateTimeImmutable($constructor['start']);
+
+        if (isset($expectations['expectedException'])) {
+            $this->expectException($expectations['expectedException']);
+            $this->expectExceptionMessage($expectations['expectedExceptionMessage']);
+        }
+
+        $interval = UsageInterval::withMonthAndFraction($month, $start, $constructor['fraction']);
+
+        $this->assertEquals($expectations['start'], $interval->start()->format("Y-m-d H:i:s"));
+        $this->assertEquals($expectations['end'], $interval->end()->format("Y-m-d H:i:s"));
+        $this->assertSame($expectations['ratioOfMonth'], $interval->ratioOfMonth());
+        $this->assertSame($expectations['seconds'], $interval->seconds());
+        $this->assertSame($expectations['secondsInMonth'], $interval->secondsInMonth());
+    }
+
+    public function provideWithMonthAndFraction()
+    {
+        yield 'For a start and end dates outside the month, the interval is the whole month' => [
+            ['month' => '2023-02-01 00:00:00', 'start' => '2023-01-01 00:00:00', 'fraction' => 1],
+            [
+                'start' => '2023-02-01 00:00:00',
+                'end' => '2023-03-01 00:00:00',
+                'ratioOfMonth' => 1.0,
+                'seconds' => 2_419_200,
+                'secondsInMonth' => 2_419_200,
+            ]
+        ];
+
+        yield 'When start date is greater than a month, the interval is a fraction of month' => [
+            ['month' => '2023-02-01 00:00:00', 'start' => '2023-02-15 00:00:00',  'fraction' => 0.5],
+            [
+                'start' => '2023-02-15 00:00:00',
+                'end' => '2023-03-01 00:00:00',
+                'ratioOfMonth' => 0.5,
+                'seconds' => 1_209_600,
+                'secondsInMonth' => 2_419_200,
+            ]
+        ];
+
+        yield 'When end date is less than a month, the interval is a fraction of month' => [
+            ['month' => '2023-02-01 00:00:00', 'start' => '2021-10-02 19:01:10',  'fraction' => 0.5],
+            [
+                'start' => '2023-02-01 00:00:00',
+                'end' => '2023-02-15 00:00:00',
+                'ratioOfMonth' => 0.5,
+                'seconds' => 1_209_600,
+                'secondsInMonth' => 2_419_200,
+            ]
+        ];
+
+        yield 'When start and end dates are within a month, the interval is a fraction of month' => [
+            ['month' => '2023-02-01 00:00:00', 'start' => '2023-02-15 00:00:00', 'fraction' => 0.17857142857142858],
+            [
+                'start' => '2023-02-15 00:00:00',
+                'end' => '2023-02-20 00:00:00',
+                'ratioOfMonth' => 0.17857142857142858,
+                'seconds' => 432_000,
+                'secondsInMonth' => 2_419_200,
+            ]
+        ];
+
+        yield 'When start date is greater than current month, the interval is zero' => [
+            ['month' => '2023-02-01 00:00:00', 'start' => '2023-03-15 00:00:00', 'fraction' => 0],
+            [
+                'start' => '2023-02-01 00:00:00',
+                'end' => '2023-02-01 00:00:00',
+                'ratioOfMonth' => 0.0,
+                'seconds' => 0,
+                'secondsInMonth' => 2_419_200,
+            ]
+        ];
+
+        yield 'When end date is less than current month, the interval is zero' => [
+            ['month' => '2023-02-01 00:00:00', 'start' => '2021-10-02 19:01:10', 'fraction' => 0],
+            [
+                'start' => '2023-02-01 00:00:00',
+                'end' => '2023-02-01 00:00:00',
+                'ratioOfMonth' => 0.0,
+                'seconds' => 0,
+                'secondsInMonth' => 2_419_200,
+            ]
+        ];
+    }
+
+    /**
+     * @dataProvider provideInvalidFractionOfMonthValues
+     */
+    public function testWithMonthAndFractionInvalidValues(float $fractionOfMonth): void
+    {
+        $month = new DateTimeImmutable('2023-01-01');
+        $start = new DateTimeImmutable('2023-01-15');
+
+        $this->expectException(\InvalidArgumentException::class);
+        $this->expectExceptionMessage('Fraction of month must be between 0 and 1');
+
+        UsageInterval::withMonthAndFraction($month, $start, $fractionOfMonth);
+    }
+
+    public function provideInvalidFractionOfMonthValues(): array
+    {
+        return [
+            [-0.1],
+            [1.1],
+            [2.0],
+        ];
+    }
 }