diff --git a/dayplot/calendar.py b/dayplot/calendar.py
index 3aef50b..1d4614d 100644
--- a/dayplot/calendar.py
+++ b/dayplot/calendar.py
@@ -50,6 +50,7 @@ def __repr__(self):
 _DEFAULT_VMIN = _DefaultArg(None)
 _DEFAULT_VMAX = _DefaultArg(None)
 _DEFAULT_VCENTER = _DefaultArg(None)
+_DEFAULT_LEGEND = _DefaultArg(False)
 _DEFAULT_LEGEND_BINS = _DefaultArg(4)
 _DEFAULT_LESS_LABEL = _DefaultArg("Less")
 _DEFAULT_MORE_LABEL = _DefaultArg("More")
@@ -262,7 +263,7 @@ def calendar(
     vmax: Any = _DEFAULT_VMAX,
     vcenter: Any = _DEFAULT_VCENTER,
     boxstyle: Union[str, patches.BoxStyle] = "square",
-    legend: bool = False,
+    legend: Any = _DEFAULT_LEGEND,
     legend_bins: Any = _DEFAULT_LEGEND_BINS,
     legend_labels: Optional[Union[List, Literal["auto"]]] = None,
     legend_labels_precision: Optional[int] = None,
@@ -334,7 +335,8 @@ def calendar(
             positive values, `vcenter` will default to 0. Providing vcenter overrides this automatic setting.
         boxstyle: The style of each box. This will be passed to `matplotlib.patches.FancyBboxPatch`.
             Available values are: "square", "circle", "ellipse", "larrow"
-        legend: Whether to display a legend for the color scale.
+        legend: Whether to display a legend for the color scale. When omitted,
+            providing another legend argument automatically displays the legend.
         legend_bins: Number of boxes/steps to display in the numeric legend.
         legend_labels: Labels for the legend boxes. Can be a list of strings or "auto"
             to generate labels from the data values. For categorical legends, None and
@@ -366,6 +368,20 @@ def calendar(
         their values. For categorical data, the last entry for a date is used.
     """
     _validate_inputs(boxstyle, dates, values)
+
+    if legend is _DEFAULT_LEGEND:
+        legend = any(
+            (
+                legend_bins is not _DEFAULT_LEGEND_BINS,
+                legend_labels is not None,
+                legend_labels_precision is not None,
+                legend_labels_kws is not None,
+                legend_kws is not None,
+                less_label is not _DEFAULT_LESS_LABEL,
+                more_label is not _DEFAULT_MORE_LABEL,
+            )
+        )
+
     is_categorical = not _is_numeric_values(values)
 
     if is_categorical:
@@ -683,7 +699,7 @@ def calendar(
 
             if legend_labels is not None:
                 if legend_labels == "auto":
-                    legend_label = round(val, ndigits=legend_labels_precision)
+                    legend_label = str(round(val, ndigits=legend_labels_precision))
                 else:
                     legend_label = str(cast(List, legend_labels)[i])
 
diff --git a/docs/tuto/legend.md b/docs/tuto/legend.md
index 07f1c9a..1fa194c 100644
--- a/docs/tuto/legend.md
+++ b/docs/tuto/legend.md
@@ -2,6 +2,9 @@
 
 You can add a very simple legend by using `legend=True`:
 
+The `legend` argument can be omitted when another legend option is provided.
+For example, `legend_bins=8` both enables the legend and sets its number of bins.
+
 ```py hl_lines="12"
 # mkdocs: render
 import matplotlib.pyplot as plt
diff --git a/tests/test_main.py b/tests/test_main.py
index 0b5e887..c9c9eb6 100644
--- a/tests/test_main.py
+++ b/tests/test_main.py
@@ -451,6 +451,53 @@ def test_legend_works(
     plt.close("all")
 
 
+@pytest.mark.parametrize(
+    "legend_kwargs",
+    [
+        {"legend_bins": 2},
+        {"legend_labels": "auto"},
+        {"legend_labels": "auto", "legend_labels_precision": 1},
+        {"legend_labels": "auto", "legend_labels_kws": {"color": "red"}},
+        {"less_label": "Low"},
+        {"more_label": "High"},
+    ],
+)
+def test_numeric_legend_arguments_enable_legend_when_legend_is_omitted(
+    legend_kwargs,
+):
+    """Test numeric legend options enable the legend without legend=True."""
+    dates = [datetime(2024, 1, 1) + timedelta(days=i) for i in range(7)]
+    values = [1, 2, 3, 4, 5, 6, 7]
+    fig, ax = plt.subplots()
+
+    rects = calendar(dates, values, ax=ax, **legend_kwargs)
+
+    assert len(ax.patches) > len(rects)
+    plt.close("all")
+
+
+@pytest.mark.parametrize(
+    "legend_kwargs",
+    [
+        {"legend_labels": ["Working", "Resting"]},
+        {"legend_labels_kws": {"color": "red"}},
+        {"legend_kws": {"ncol": 1}},
+    ],
+)
+def test_categorical_legend_arguments_enable_legend_when_legend_is_omitted(
+    legend_kwargs,
+):
+    """Test categorical legend options enable the legend without legend=True."""
+    dates = [datetime(2024, 1, 1), datetime(2024, 1, 2)]
+    values = ["work", "rest"]
+    fig, ax = plt.subplots()
+
+    calendar(dates, values, ax=ax, **legend_kwargs)
+
+    assert ax.get_legend() is not None
+    plt.close("all")
+
+
 @pytest.mark.parametrize("month_grid", [True, False])
 @pytest.mark.parametrize(
     "month_grid_kws", [{}, {"edgecolor": (0, 0, 1, 1), "linestyle": "--"}]