diff --git a/public/app/core/utils/kbn.test.ts b/public/app/core/utils/kbn.test.ts
index df31dbbdc2b..80dd53ed5b3 100644
--- a/public/app/core/utils/kbn.test.ts
+++ b/public/app/core/utils/kbn.test.ts
@@ -50,3 +50,26 @@ describe('Chcek KBN value formats', () => {
     });
   }
 });
+
+describe('describe_interval', () => {
+  it('falls back to seconds if input is a number', () => {
+    expect(kbn.describe_interval('123')).toEqual({
+      sec: 1,
+      type: 's',
+      count: 123,
+    });
+  });
+
+  it('parses a valid time unt string correctly', () => {
+    expect(kbn.describe_interval('123h')).toEqual({
+      sec: 3600,
+      type: 'h',
+      count: 123,
+    });
+  });
+
+  it('fails if input is invalid', () => {
+    expect(() => kbn.describe_interval('123xyz')).toThrow();
+    expect(() => kbn.describe_interval('xyz')).toThrow();
+  });
+});
diff --git a/public/app/core/utils/kbn.ts b/public/app/core/utils/kbn.ts
index 77bc252f6f6..ca786d56b25 100644
--- a/public/app/core/utils/kbn.ts
+++ b/public/app/core/utils/kbn.ts
@@ -200,9 +200,22 @@ kbn.calculateInterval = (range: TimeRange, resolution: number, lowLimitInterval:
 };
 
 kbn.describe_interval = (str: string) => {
+  // Default to seconds if no unit is provided
+  if (Number(str)) {
+    return {
+      sec: kbn.intervals_in_seconds.s,
+      type: 's',
+      count: parseInt(str, 10),
+    };
+  }
+
   const matches = str.match(kbn.interval_regex);
   if (!matches || !has(kbn.intervals_in_seconds, matches[2])) {
-    throw new Error('Invalid interval string, expecting a number followed by one of "Mwdhmsy"');
+    throw new Error(
+      `Invalid interval string, has to be either unit-less or end with one of the following units: "${Object.keys(
+        kbn.intervals_in_seconds
+      ).join(', ')}"`
+    );
   } else {
     return {
       sec: kbn.intervals_in_seconds[matches[2]],
diff --git a/public/app/features/variables/interval/actions.test.ts b/public/app/features/variables/interval/actions.test.ts
index 973f7862c6f..c47d391f213 100644
--- a/public/app/features/variables/interval/actions.test.ts
+++ b/public/app/features/variables/interval/actions.test.ts
@@ -18,6 +18,7 @@ import { AppEvents, dateTime } from '@grafana/data';
 import { getTimeSrv, setTimeSrv, TimeSrv } from '../../dashboard/services/TimeSrv';
 import { TemplateSrv } from '../../templating/template_srv';
 import { intervalBuilder } from '../shared/testing/builders';
+import kbn from 'app/core/utils/kbn';
 
 describe('interval actions', () => {
   variableAdapters.setInit(() => [createIntervalVariableAdapter()]);
@@ -65,7 +66,7 @@ describe('interval actions', () => {
         .withId('0')
         .withQuery('1s,1m,1h,1d')
         .withAuto(true)
-        .withAutoMin('1') // illegal interval string
+        .withAutoMin('1xyz') // illegal interval string
         .build();
       const appEventMock = ({
         emit: jest.fn(),
@@ -80,7 +81,9 @@ describe('interval actions', () => {
       expect(appEventMock.emit).toHaveBeenCalledTimes(1);
       expect(appEventMock.emit).toHaveBeenCalledWith(AppEvents.alertError, [
         'Templating',
-        'Invalid interval string, expecting a number followed by one of "Mwdhmsy"',
+        `Invalid interval string, has to be either unit-less or end with one of the following units: "${Object.keys(
+          kbn.intervals_in_seconds
+        ).join(', ')}"`,
       ]);
       setTimeSrv(originalTimeSrv);
     });
diff --git a/public/app/plugins/datasource/prometheus/components/PromExploreQueryEditor.tsx b/public/app/plugins/datasource/prometheus/components/PromExploreQueryEditor.tsx
index f7f8d9cf34e..5add4d8face 100644
--- a/public/app/plugins/datasource/prometheus/components/PromExploreQueryEditor.tsx
+++ b/public/app/plugins/datasource/prometheus/components/PromExploreQueryEditor.tsx
@@ -48,7 +48,9 @@ export function PromExploreQueryEditor(props: Props) {
           onKeyDownFunc={onReturnKeyDown}
           value={query.interval || ''}
           hasTooltip={true}
-          tooltipContent={'Needs to be a valid time unit string, for example 5s, 1m, 3h, 1d, 1y'}
+          tooltipContent={
+            'Time units can be used here, for example: 5s, 1m, 3h, 1d, 1y (Default if no unit is specified: s)'
+          }
         />
       }
     />
diff --git a/public/app/plugins/datasource/prometheus/components/__snapshots__/PromExploreQueryEditor.test.tsx.snap b/public/app/plugins/datasource/prometheus/components/__snapshots__/PromExploreQueryEditor.test.tsx.snap
index f8995e8918a..2670a2a4237 100644
--- a/public/app/plugins/datasource/prometheus/components/__snapshots__/PromExploreQueryEditor.test.tsx.snap
+++ b/public/app/plugins/datasource/prometheus/components/__snapshots__/PromExploreQueryEditor.test.tsx.snap
@@ -8,7 +8,7 @@ exports[`PromExploreQueryEditor should render component 1`] = `
       label="Step"
       onChangeFunc={[Function]}
       onKeyDownFunc={[Function]}
-      tooltipContent="Needs to be a valid time unit string, for example 5s, 1m, 3h, 1d, 1y"
+      tooltipContent="Time units can be used here, for example: 5s, 1m, 3h, 1d, 1y (Default if no unit is specified: s)"
       value="1s"
     />
   }