diff --git a/packages/client/src/utils/__tests__/utils.test.ts b/packages/client/src/utils/__tests__/utils.test.ts
index fb74bab9c..c31823026 100644
--- a/packages/client/src/utils/__tests__/utils.test.ts
+++ b/packages/client/src/utils/__tests__/utils.test.ts
@@ -38,6 +38,7 @@ describe("Helpers", () => {
     });
 
     test("should convert string to number", () => {
+      const halfStr = "21:00 - 21:20";
       const oneStr = "16:00 - 17:00";
       const oneHalfStr = "22:00 - 23:30";
       const twoStr = "22:00 - 24:00";
@@ -46,9 +47,11 @@ describe("Helpers", () => {
       // const morningResult = convertIntervalToNum(morningStr);
       const oneResult = calculateIntervalDuration(oneStr);
       const oneHalfResult = calculateIntervalDuration(oneHalfStr);
+      const halfResult = calculateIntervalDuration(halfStr);
       const twoResult = calculateIntervalDuration(twoStr);
       const nonStdResult = calculateIntervalDuration(nonStdStr);
 
+      expect(halfResult).toBe(0.5);
       expect(oneResult).toBe(1);
       expect(oneHalfResult).toBe(1.5);
       expect(twoResult).toBe(2);
diff --git a/packages/client/src/utils/helpers.ts b/packages/client/src/utils/helpers.ts
index 53dd2b8f5..372bf5f27 100644
--- a/packages/client/src/utils/helpers.ts
+++ b/packages/client/src/utils/helpers.ts
@@ -102,6 +102,7 @@ const getMillisFromMidnight = (time: string) =>
  * @param {string | null} interval - String slot interval
  * Converts a string slot interval to a number e.g:
  * `null => 0`;
+ * `"21:00 - 21:20" => 0.5`;
  * `"16:00 - 17:00" => 1.0`;
  * `"22:00 - 23:30" => 1.5`;
  * `"22:00 - 24:00" => 2`;
@@ -118,11 +119,7 @@ export const calculateIntervalDuration = (interval: string | null) => {
   const diffMillis =
     getMillisFromMidnight(endTime) - getMillisFromMidnight(startTime);
 
-  return diffMillis <= hourInMillis
-    ? 1
-    : diffMillis <= hourInMillis * 1.5
-    ? 1.5
-    : 2;
+  return Math.ceil((diffMillis / hourInMillis) * 2) * 0.5;
 };
 /**
  * interpolate text including <p/>
diff --git a/packages/ui/src/IntervalCard/BookingCardContainer.tsx b/packages/ui/src/IntervalCard/BookingCardContainer.tsx
index 26d8ea2b7..9f9f25309 100644
--- a/packages/ui/src/IntervalCard/BookingCardContainer.tsx
+++ b/packages/ui/src/IntervalCard/BookingCardContainer.tsx
@@ -29,6 +29,7 @@ const BookingCardContainer: React.FC<BookingContainerProps> = ({
 };
 
 const containerSizeLookup = {
+  [IntervalDuration["0.5h"]]: ["w-[200px]", "min-h-[110px]", "px-4", "py-2.5"],
   [IntervalDuration["1h"]]: ["w-[220px]", "min-h-[110px]", "px-4", "py-2.5"],
   [IntervalDuration["1.5h"]]: ["w-[320px]", "h-[128px]", "px-4", "py-3"],
   [IntervalDuration["2h"]]: ["w-[401px]", "h-[146px]", "px-4", "py-3"],
diff --git a/packages/ui/src/IntervalCard/CardContent.tsx b/packages/ui/src/IntervalCard/CardContent.tsx
index 055590aac..28b1adf61 100644
--- a/packages/ui/src/IntervalCard/CardContent.tsx
+++ b/packages/ui/src/IntervalCard/CardContent.tsx
@@ -80,6 +80,7 @@ const getTimestringClasses = (
   ].join(" ");
 
 const timestringBookingSizeLookup = {
+  [IntervalDuration["0.5h"]]: ["mb-2", "text-md", "leading-8", "font-semibold"],
   [IntervalDuration["1h"]]: ["mb-2", "text-lg", "leading-8", "font-semibold"],
   [IntervalDuration["1.5h"]]: [
     "mb-2",
diff --git a/packages/ui/src/IntervalCard/__tests__/intervalCardUtils.test.ts b/packages/ui/src/IntervalCard/__tests__/intervalCardUtils.test.ts
index e2445fe09..63418b3bf 100644
--- a/packages/ui/src/IntervalCard/__tests__/intervalCardUtils.test.ts
+++ b/packages/ui/src/IntervalCard/__tests__/intervalCardUtils.test.ts
@@ -21,6 +21,10 @@ const runCalculateDurationTableTests = (tests: TestParams[]) => {
 describe("IntervalCard", () => {
   describe("calculateDuration util", () => {
     runCalculateDurationTableTests([
+      { startTime: "09:00", endTime: "09:15", want: IntervalDuration["0.5h"] },
+      { startTime: "09:00", endTime: "09:20", want: IntervalDuration["0.5h"] },
+      { startTime: "09:00", endTime: "09:30", want: IntervalDuration["0.5h"] },
+
       { startTime: "09:00", endTime: "09:40", want: IntervalDuration["1h"] },
       { startTime: "09:00", endTime: "09:50", want: IntervalDuration["1h"] },
       { startTime: "09:00", endTime: "10:00", want: IntervalDuration["1h"] },
diff --git a/packages/ui/src/IntervalCard/types.ts b/packages/ui/src/IntervalCard/types.ts
index 19cf9888e..2435ab0ef 100644
--- a/packages/ui/src/IntervalCard/types.ts
+++ b/packages/ui/src/IntervalCard/types.ts
@@ -17,6 +17,7 @@ export enum IntervalCardVariant {
 }
 
 export enum IntervalDuration {
+  "0.5h",
   "1h",
   "1.5h",
   "2h",
diff --git a/packages/ui/src/IntervalCard/utils.ts b/packages/ui/src/IntervalCard/utils.ts
index 1a192a701..bdf275587 100644
--- a/packages/ui/src/IntervalCard/utils.ts
+++ b/packages/ui/src/IntervalCard/utils.ts
@@ -17,9 +17,6 @@ export const calculateDuration = (startTime: string, endTime: string) => {
   const diffMillis =
     getMillisFromMidnight(endTime) - getMillisFromMidnight(startTime);
 
-  return diffMillis <= hourInMillis
-    ? IntervalDuration["1h"]
-    : diffMillis <= hourInMillis * 1.5
-    ? IntervalDuration["1.5h"]
-    : IntervalDuration["2h"];
+  const duration = `${Math.ceil((diffMillis / hourInMillis) * 2) * 0.5}h`;
+  return IntervalDuration[duration];
 };