diff --git a/README.md b/README.md
index 501006b..45b65f4 100644
--- a/README.md
+++ b/README.md
@@ -256,8 +256,8 @@ The position of the marker will only update when the card updates (state change
 
 | Name | Since | Description |
 | ---- | :---: | ----------- |
-| `start` | v1.2.0 | Display the graph from the begining of the `minute`, `day`, `hour`, `week`, `month`, `year` |
-| `end` | v1.2.0 | Display the graph from the end of the `minute`, `day`, `hour`, `week`, `month`, `year` |
+| `start` | v1.2.0 | Display the graph from the begining of the `minute`, `day`, `hour`, `week`, `month`, `year`, `isoWeek`. `isoWeek` is the start of the week according to ISO 8601 |
+| `end` | v1.2.0 | Display the graph from the end of the `minute`, `day`, `hour`, `week`, `month`, `year`, `isoWeek`. `isoWeek` is the end of the week according to ISO 8601 |
 | `offset` | v1.2.0 | Offset the graph by an amount of time. To offset in the past, start with `-`. Eg. of valid values: `-1day`, `-12h`, `12h`, `30min`, ... `month` (365.25 days / 12) and `year` (365.25 days) as unit will generate inconsistent result, you should use days instead. |
 
 Span enables you to:
diff --git a/src/types-config-ti.ts b/src/types-config-ti.ts
index a9d5d54..06c6a57 100644
--- a/src/types-config-ti.ts
+++ b/src/types-config-ti.ts
@@ -50,11 +50,13 @@ export const ChartCardBrushExtConfig = t.iface([], {
 });
 
 export const ChartCardSpanExtConfig = t.iface([], {
-  "start": t.opt(t.union(t.lit('minute'), t.lit('hour'), t.lit('day'), t.lit('week'), t.lit('month'), t.lit('year'))),
-  "end": t.opt(t.union(t.lit('minute'), t.lit('hour'), t.lit('day'), t.lit('week'), t.lit('month'), t.lit('year'))),
+  "start": t.opt("ChartCardStartEnd"),
+  "end": t.opt("ChartCardStartEnd"),
   "offset": t.opt("string"),
 });
 
+export const ChartCardStartEnd = t.union(t.lit('minute'), t.lit('hour'), t.lit('day'), t.lit('week'), t.lit('month'), t.lit('year'), t.lit('isoWeek'));
+
 export const ChartCardAllSeriesExternalConfig = t.iface([], {
   "entity": t.opt("string"),
   "attribute": t.opt("string"),
@@ -124,6 +126,7 @@ const exportedTypeSuite: t.ITypeSuite = {
   ChartCardChartType,
   ChartCardBrushExtConfig,
   ChartCardSpanExtConfig,
+  ChartCardStartEnd,
   ChartCardAllSeriesExternalConfig,
   ChartCardSeriesExternalConfig,
   ChartCardPrettyTime,
diff --git a/src/types-config.ts b/src/types-config.ts
index 62ad498..432d68c 100644
--- a/src/types-config.ts
+++ b/src/types-config.ts
@@ -49,11 +49,13 @@ export interface ChartCardBrushExtConfig {
 }
 
 export interface ChartCardSpanExtConfig {
-  start?: 'minute' | 'hour' | 'day' | 'week' | 'month' | 'year';
-  end?: 'minute' | 'hour' | 'day' | 'week' | 'month' | 'year';
+  start?: ChartCardStartEnd;
+  end?: ChartCardStartEnd;
   offset?: string;
 }
 
+export type ChartCardStartEnd = 'minute' | 'hour' | 'day' | 'week' | 'month' | 'year' | 'isoWeek';
+
 export interface ChartCardAllSeriesExternalConfig {
   entity?: string;
   attribute?: string;