diff --git a/CHANGELOG.md b/CHANGELOG.md
index e1a5aeb..5f3ce76 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -9,6 +9,12 @@ See [GitHub releases](https://github.com/mll-lab/laravel-utils/releases).
 
 ## Unreleased
 
+## v5.2.0
+
+### Added
+
+- Round floats in `UnsignedInt` cast
+
 ## v5.1.0
 
 ### Added
diff --git a/php.dockerfile b/php.dockerfile
index 74924c9..dc809b9 100644
--- a/php.dockerfile
+++ b/php.dockerfile
@@ -5,17 +5,18 @@ WORKDIR /workdir
 COPY --from=composer /usr/bin/composer /usr/bin/composer
 
 RUN apt-get update && \
-    apt-get install -y \
+    apt-get install --yes \
         git \
         libzip-dev \
         zip \
         libicu-dev \
+    && rm -rf /var/lib/apt/lists/* \
     && docker-php-ext-install \
+        calendar \
         zip \
         mysqli \
         pdo_mysql \
         intl \
-    && rm -rf /var/lib/apt/lists/* \
     && pecl install \
         xdebug \
         redis \
diff --git a/src/Casts/UnsignedInt.php b/src/Casts/UnsignedInt.php
index d83e6a7..4339352 100644
--- a/src/Casts/UnsignedInt.php
+++ b/src/Casts/UnsignedInt.php
@@ -21,9 +21,7 @@ class UnsignedInt implements CastsAttributes
      */
     public function get($model, $key, $value, $attributes): int
     {
-        assert(is_int($value));
-
-        return max(0, $value);
+        return $this->cast($value);
     }
 
     /**
@@ -33,7 +31,20 @@ public function get($model, $key, $value, $attributes): int
      */
     public function set($model, $key, $value, $attributes): int
     {
-        assert(is_int($value));
+        return $this->cast($value);
+    }
+
+    protected function cast(mixed $value): int
+    {
+        if (is_float($value)) {
+            $value = (int) round($value);
+        }
+
+        if (! is_int($value)) {
+            $type = gettype($value);
+            $valueString = var_export($value, true);
+            throw new \RuntimeException("Expected int, got {$type}: {$valueString}.");
+        }
 
         return max(0, $value);
     }
diff --git a/tests/Casts/UnsignedIntTest.php b/tests/Casts/UnsignedIntTest.php
index 1fe8fb8..8317f79 100644
--- a/tests/Casts/UnsignedIntTest.php
+++ b/tests/Casts/UnsignedIntTest.php
@@ -23,7 +23,19 @@ public function testCast(): void
         $model->unsigned_int = 2;
         self::assertSame(2, $model->getRawAttribute('unsigned_int'));
 
+        $model->unsigned_int = 2.4999; // @phpstan-ignore-line should round floats
+        self::assertSame(2, $model->getRawAttribute('unsigned_int'));
+
+        $model->unsigned_int = 2.5001; // @phpstan-ignore-line should round floats
+        self::assertSame(3, $model->getRawAttribute('unsigned_int'));
+
         $model->setRawAttribute('unsigned_int', -1);
         self::assertSame(0, $model->unsigned_int);
+
+        $model->setRawAttribute('unsigned_int', 1.1);
+        self::assertSame(1, $model->unsigned_int);
+
+        $this->expectExceptionObject(new \RuntimeException('Expected int, got string: "foo".'));
+        $model->unsigned_int = 'foo'; // @phpstan-ignore-line intentionally wrong
     }
 }