diff --git a/hiplot/experiment.py b/hiplot/experiment.py
index 8925fc3f..bb11cc8d 100644
--- a/hiplot/experiment.py
+++ b/hiplot/experiment.py
@@ -191,6 +191,9 @@ class Experiment(_DictSerializable):
 
     :ivar datapoints: All the measurements we have. One datapoint corresponds to one line in the parallel plot and to one line in the table.
     :ivar parameters_definition: Characteristics of the columns (ordering, type, etc...)
+    :ivar colormap: Colormap to use
+    :ivar colorby: Default column to color by
+    :ivar weightcolumn: If rows have different weights, use this column as the weight (default to 1 if not specified)
 
     :Example:
 
@@ -212,6 +215,7 @@ def __init__(self,
         self.parameters_definition = parameters_definition if parameters_definition is not None else defaultdict(ValueDef)
         self.colormap = colormap if colormap is not None else "interpolateTurbo"
         self.colorby: tp.Optional[str] = None
+        self.weightcolumn: tp.Optional[str] = None
         self._display_data: tp.Dict[str, tp.Dict[str, tp.Any]] = {}
         self._compress: bool = False
 
@@ -394,6 +398,7 @@ def _asdict(self) -> tp.Dict[str, tp.Any]:
             "parameters_definition": {k: v._asdict() for k, v in self.parameters_definition.items()},
             "colormap": self.colormap,
             "colorby": self.colorby,
+            "weightcolumn": self.weightcolumn,
             "display_data": self._display_data,
         }
         if self._compress:
diff --git a/hiplot/fetchers_demo.py b/hiplot/fetchers_demo.py
index cf24bb10..b7b48cb3 100644
--- a/hiplot/fetchers_demo.py
+++ b/hiplot/fetchers_demo.py
@@ -296,6 +296,20 @@ def demo_first_value_nan() -> hip.Experiment:
     ])
 
 
+def demo_weighted_rows() -> hip.Experiment:
+    experiment = hip.Experiment.from_iterable([
+        {'w': 1.0, 'a': 1, 'b': 1},
+        {'w': 2.0, 'a': 2, 'b': 1},
+        {'w': -2.0, 'a': 2, 'b': 1},
+        {'w': math.inf, 'a': 2, 'b': 2},
+        {'w': 'not_a_number', 'a': 2, 'b': 3},
+        {'w': None, 'a': 3, 'b': 3},
+        {'a': 4, 'b': 3},
+    ])
+    experiment.weightcolumn = "w"
+    return experiment
+
+
 README_DEMOS: t.Dict[str, t.Callable[[], hip.Experiment]] = {
     "demo": demo,
     "demo_big": lambda: demo(1000),
@@ -318,4 +332,5 @@ def demo_first_value_nan() -> hip.Experiment:
     "demo_force_constant_pplot": demo_force_constant_pplot,
     "demo_color_interpolate_inverse": demo_color_interpolate_inverse,
     "demo_first_value_nan": demo_first_value_nan,
+    "demo_weighted_rows": demo_weighted_rows,
 }
diff --git a/src/component.tsx b/src/component.tsx
index c5b85a29..54a80506 100644
--- a/src/component.tsx
+++ b/src/component.tsx
@@ -536,6 +536,7 @@ export class HiPlot extends React.Component<HiPlotProps, HiPlotState> {
             <div className={`${style.hiplot} ${this.state.dark ? style.dark : ""}`}>
             <SelectedCountProgressBar {...controlProps} />
             <HeaderBar
+                weightColumn={this.state.experiment ? this.state.experiment.weightcolumn : undefined}
                 onLoadExperiment={this.loadWithPromise.bind(this)}
                 persistentState={this.state.persistentState}
                 dataProvider={this.state.dataProvider}
diff --git a/src/header.tsx b/src/header.tsx
index 9fd1b916..c17c73f2 100644
--- a/src/header.tsx
+++ b/src/header.tsx
@@ -7,7 +7,7 @@
 
 import style from "./hiplot.scss";
 import React from "react";
-import { HiPlotLoadStatus, IDatasets } from "./types";
+import { Datapoint, HiPlotLoadStatus, IDatasets } from "./types";
 import { HiPlotDataControlProps, RestoreDataBtn, ExcludeDataBtn, ExportDataCSVBtn, KeepDataBtn } from "./controls";
 import { DataProviderClass, DataProviderComponentClass, DataProviderProps} from "./plugin";
 
@@ -22,6 +22,7 @@ import { PersistentState } from "./lib/savedstate";
 
 
 interface HeaderBarProps extends IDatasets, HiPlotDataControlProps {
+    weightColumn?: string;
     loadStatus: HiPlotLoadStatus; // Should not allow to load an xp when already loading another xp
     persistentState: PersistentState;
     onLoadExperiment: (load_promise: Promise<any>) => void;
@@ -33,13 +34,12 @@ interface HeaderBarProps extends IDatasets, HiPlotDataControlProps {
 interface HeaderBarState {
     isTextareaFocused: boolean;
     hasTutorial: boolean;
+    selectedPct: string;
+    selectedPctWeighted: string;
 };
 
 export class HeaderBar extends React.Component<HeaderBarProps, HeaderBarState> {
     dataProviderRef = React.createRef<DataProviderClass>();
-    selected_count_ref: React.RefObject<HTMLElement> = React.createRef();
-    selected_pct_ref: React.RefObject<HTMLElement> = React.createRef();
-    total_count_ref: React.RefObject<HTMLElement> = React.createRef();
     controls_root_ref: React.RefObject<HTMLDivElement> = React.createRef();
 
     constructor(props: HeaderBarProps) {
@@ -47,23 +47,51 @@ export class HeaderBar extends React.Component<HeaderBarProps, HeaderBarState> {
         this.state = {
             isTextareaFocused: false,
             hasTutorial: false,
+            selectedPct: '???',
+            selectedPctWeighted: '???',
         };
     }
     recomputeMetrics() {
-        if (!this.selected_count_ref.current) {
+        const newSelectedPct = (100 * this.props.rows_selected.length / this.props.rows_filtered.length).toPrecision(3);
+        if (newSelectedPct != this.state.selectedPct) {
+            this.setState({
+                selectedPct: (100 * this.props.rows_selected.length / this.props.rows_filtered.length).toPrecision(3)
+            });
+        }
+    }
+    recomputeSelectedWeightedSum() {
+        if (!this.props.weightColumn) {
+            this.setState({
+                selectedPctWeighted: '???',
+            });
             return;
         }
-        const selected_count = this.props.rows_selected.length;
-        const total_count = this.props.rows_filtered.length;
-        this.selected_count_ref.current.innerText = '' + selected_count;
-        this.selected_pct_ref.current.innerText = '' + (100 * selected_count / total_count).toPrecision(3);
-        this.total_count_ref.current.innerText = '' + total_count;
+        const getWeight = function(dp: Datapoint): number {
+            const w = parseFloat(dp[this.props.weightColumn]);
+            return !isNaN(w) && isFinite(w) && w > 0.0 ? w : 1.0;
+        }.bind(this);
+        var totalWeightFiltered = 0.0, totalWeightSelected = 0.0;
+        this.props.rows_filtered.forEach(function(dp: Datapoint) {
+            totalWeightFiltered += getWeight(dp);
+        });
+        this.props.rows_selected.forEach(function(dp: Datapoint) {
+            totalWeightSelected += getWeight(dp);
+        });
+        const pctage = (100 * totalWeightSelected / totalWeightFiltered);
+        console.assert(!isNaN(pctage), {"pctage": pctage, "totalWeightFiltered": totalWeightFiltered, "totalWeightSelected": totalWeightSelected});
+        this.setState({
+            selectedPctWeighted: pctage.toPrecision(3)
+        });
     }
     componentDidMount() {
         this.recomputeMetrics();
+        this.recomputeSelectedWeightedSum();
     }
-    componentDidUpdate() {
+    componentDidUpdate(prevProps: HeaderBarProps, prevState: HeaderBarState): void {
         this.recomputeMetrics();
+        if (prevProps.weightColumn != this.props.weightColumn || this.props.rows_selected != prevProps.rows_selected || this.props.rows_filtered != prevProps.rows_filtered) {
+            this.recomputeSelectedWeightedSum();
+        }
     }
     onToggleTutorial() {
         this.setState(function(prevState, prevProps) {
@@ -107,9 +135,15 @@ export class HeaderBar extends React.Component<HeaderBarProps, HeaderBarState> {
                     </div>
                     <div className={style.controlGroup}>
                         <div style={{"fontFamily": "monospace", "fontSize": "14px"}}>
-            Selected: <strong ref={this.selected_count_ref} style={{"minWidth": "4em", "textAlign": "right", "display": "inline-block"}}>??</strong>
-                    /<strong ref={this.total_count_ref} style={{"minWidth": "4em", "textAlign": "left", "display": "inline-block"}}>??</strong> (
-                        <span style={{"minWidth": "3em", "textAlign": "right", "display": "inline-block"}} ref={this.selected_pct_ref}>??</span>%)
+            Selected: <strong style={{"minWidth": "4em", "textAlign": "right", "display": "inline-block"}}>{this.props.rows_selected.length}</strong>
+                    /<strong style={{"minWidth": "4em", "textAlign": "left", "display": "inline-block"}}>{this.props.rows_filtered.length}</strong> (
+                        {!this.props.weightColumn &&
+                            <React.Fragment><span style={{"minWidth": "3em", "textAlign": "right", "display": "inline-block"}}>{this.state.selectedPct}</span>%</React.Fragment>
+                        }
+                        {this.props.weightColumn &&
+                            <React.Fragment><span style={{"minWidth": "3em", "textAlign": "right", "display": "inline-block"}}>{this.state.selectedPctWeighted}</span>% weighted</React.Fragment>
+                        }
+                        )
                         </div>
                     </div>
                 </React.Fragment>
diff --git a/src/types.ts b/src/types.ts
index 1f465e56..29723676 100644
--- a/src/types.ts
+++ b/src/types.ts
@@ -48,6 +48,7 @@ export interface HiPlotExperiment { // Mirror of python `hip.Experiment`
     parameters_definition?: {[key: string]: HiPlotValueDef},
     colormap?: string;
     colorby?: string;
+    weightcolumn?: string;
     display_data?: {[key: string]: {[key2: string]: any}},
 }