diff --git a/ironfish-cli/src/utils/spendPostTime.ts b/ironfish-cli/src/utils/spendPostTime.ts
index cf43bb5067..f766c29b66 100644
--- a/ironfish-cli/src/utils/spendPostTime.ts
+++ b/ironfish-cli/src/utils/spendPostTime.ts
@@ -22,15 +22,23 @@ export async function updateSpendPostTimeInMs(
   startTime: number,
   endTime: number,
 ) {
-  const totalTime = endTime - startTime
-  const transactionSpendPostTime = Math.ceil(totalTime / raw.spends.length)
-  let spendPostTime = sdk.internal.get('spendPostTime')
-  if (transactionSpendPostTime > spendPostTime) {
-    spendPostTime = transactionSpendPostTime
-    sdk.internal.set('spendPostTime', spendPostTime)
-    sdk.internal.set('spendPostTimeAt', Date.now())
-    await sdk.internal.save()
+  const total = endTime - startTime
+  const current = Math.ceil(total / raw.spends.length)
+
+  const old = sdk.internal.get('spendPostTime')
+  const oldCount = sdk.internal.get('spendPostTimeMeasurements')
+
+  const newCount = oldCount + 1
+  let newSpendPostTime = current
+
+  if (oldCount > 1) {
+    newSpendPostTime = (old * oldCount + current) / newCount
   }
+
+  sdk.internal.set('spendPostTime', newSpendPostTime)
+  sdk.internal.set('spendPostTimeAt', Date.now())
+  sdk.internal.set('spendPostTimeMeasurements', newCount)
+  await sdk.internal.save()
 }
 
 export function getSpendPostTimeInMs(sdk: IronfishSdk): number {
diff --git a/ironfish/src/fileStores/internal.ts b/ironfish/src/fileStores/internal.ts
index 1ce7251f42..0b2a62f030 100644
--- a/ironfish/src/fileStores/internal.ts
+++ b/ironfish/src/fileStores/internal.ts
@@ -12,6 +12,7 @@ export type InternalOptions = {
   rpcAuthToken: string
   networkId: number
   spendPostTime: number // in milliseconds
+  spendPostTimeMeasurements: number // used to calculate the average spendPostTime
   spendPostTimeAt: number // when the spend post time measurement was done
 }
 
@@ -22,6 +23,7 @@ export const InternalOptionsDefaults: InternalOptions = {
   rpcAuthToken: '',
   networkId: DEFAULT_NETWORK_ID,
   spendPostTime: 0,
+  spendPostTimeMeasurements: 0,
   spendPostTimeAt: 0,
 }