diff --git a/server/src/main/java/org/elasticsearch/common/Rounding.java b/server/src/main/java/org/elasticsearch/common/Rounding.java
index ebfa043333ade..c795fa8cd3ca2 100644
--- a/server/src/main/java/org/elasticsearch/common/Rounding.java
+++ b/server/src/main/java/org/elasticsearch/common/Rounding.java
@@ -240,9 +240,9 @@ public interface Prepared {
 
     /**
      * Rounds the given value.
-     * <p>
-     * Prefer {@link #prepare(long, long)} if rounding many values.
+     * @deprecated Prefer {@link #prepare} and then {@link Prepared#round(long)}
      */
+    @Deprecated
     public final long round(long utcMillis) {
         return prepare(utcMillis, utcMillis).round(utcMillis);
     }
@@ -252,9 +252,9 @@ public final long round(long utcMillis) {
      * {@link #round(long)}, returns the next rounding value. For
      * example, with interval based rounding, if the interval is
      * 3, {@code nextRoundValue(6) = 9}.
-     * <p>
-     * Prefer {@link #prepare(long, long)} if rounding many values.
+     * @deprecated Prefer {@link #prepare} and then {@link Prepared#nextRoundingValue(long)}
      */
+    @Deprecated
     public final long nextRoundingValue(long utcMillis) {
         return prepare(utcMillis, utcMillis).nextRoundingValue(utcMillis);
     }
diff --git a/server/src/test/java/org/elasticsearch/common/rounding/RoundingDuelTests.java b/server/src/test/java/org/elasticsearch/common/rounding/RoundingDuelTests.java
index b791d0e3ce9dd..2bba52a0b7591 100644
--- a/server/src/test/java/org/elasticsearch/common/rounding/RoundingDuelTests.java
+++ b/server/src/test/java/org/elasticsearch/common/rounding/RoundingDuelTests.java
@@ -60,16 +60,16 @@ public void testSerialization() throws Exception {
     public void testDuellingImplementations() {
         org.elasticsearch.common.Rounding.DateTimeUnit randomDateTimeUnit =
             randomFrom(org.elasticsearch.common.Rounding.DateTimeUnit.values());
-        org.elasticsearch.common.Rounding rounding;
+        org.elasticsearch.common.Rounding.Prepared rounding;
         Rounding roundingJoda;
 
         if (randomBoolean()) {
-            rounding = org.elasticsearch.common.Rounding.builder(randomDateTimeUnit).timeZone(ZoneOffset.UTC).build();
+            rounding = org.elasticsearch.common.Rounding.builder(randomDateTimeUnit).timeZone(ZoneOffset.UTC).build().prepareForUnknown();
             DateTimeUnit dateTimeUnit = DateTimeUnit.resolve(randomDateTimeUnit.getId());
             roundingJoda = Rounding.builder(dateTimeUnit).timeZone(DateTimeZone.UTC).build();
         } else {
             TimeValue interval = timeValue();
-            rounding = org.elasticsearch.common.Rounding.builder(interval).timeZone(ZoneOffset.UTC).build();
+            rounding = org.elasticsearch.common.Rounding.builder(interval).timeZone(ZoneOffset.UTC).build().prepareForUnknown();
             roundingJoda = Rounding.builder(interval).timeZone(DateTimeZone.UTC).build();
         }
 
diff --git a/server/src/test/java/org/elasticsearch/search/aggregations/bucket/histogram/InternalAutoDateHistogramTests.java b/server/src/test/java/org/elasticsearch/search/aggregations/bucket/histogram/InternalAutoDateHistogramTests.java
index fd49e57e7c9aa..4d7e9b731a56e 100644
--- a/server/src/test/java/org/elasticsearch/search/aggregations/bucket/histogram/InternalAutoDateHistogramTests.java
+++ b/server/src/test/java/org/elasticsearch/search/aggregations/bucket/histogram/InternalAutoDateHistogramTests.java
@@ -157,6 +157,7 @@ protected void assertReduced(InternalAutoDateHistogram reduced, List<InternalAut
 
         int roundingIndex = reduced.getBucketInfo().roundingIdx;
         RoundingInfo roundingInfo = AutoDateHistogramAggregationBuilder.buildRoundings(null, null)[roundingIndex];
+        Rounding.Prepared prepared = roundingInfo.rounding.prepare(lowest, highest);
 
         long normalizedDuration = (highest - lowest) / roundingInfo.getRoughEstimateDurationMillis();
         int innerIntervalIndex = 0;
@@ -185,7 +186,7 @@ protected void assertReduced(InternalAutoDateHistogram reduced, List<InternalAut
         } else {
             do {
                 innerIntervalToUse = roundingInfo.innerIntervals[innerIntervalIndex];
-                int bucketCountAtInterval = getBucketCount(lowest, highest, roundingInfo.rounding, innerIntervalToUse);
+                int bucketCountAtInterval = getBucketCount(lowest, highest, prepared, innerIntervalToUse);
                 if (bucketCountAtInterval == reduced.getBuckets().size()) {
                     break;
                 }
@@ -199,11 +200,11 @@ protected void assertReduced(InternalAutoDateHistogram reduced, List<InternalAut
         assertThat(reduced.getInterval().toString(), equalTo(innerIntervalToUse + roundingInfo.unitAbbreviation));
         Map<Instant, Long> expectedCounts = new TreeMap<>();
         if (totalBucketConut > 0) {
-            long keyForBucket = roundingInfo.rounding.round(lowest);
-            while (keyForBucket <= roundingInfo.rounding.round(highest)) {
+            long keyForBucket = prepared.round(lowest);
+            while (keyForBucket <= prepared.round(highest)) {
                 long nextKey = keyForBucket;
                 for (int i = 0; i < innerIntervalToUse; i++) {
-                    nextKey = roundingInfo.rounding.nextRoundingValue(nextKey);
+                    nextKey = prepared.nextRoundingValue(nextKey);
                 }
                 Instant key = Instant.ofEpochMilli(keyForBucket);
                 expectedCounts.put(key, 0L);
@@ -214,7 +215,7 @@ protected void assertReduced(InternalAutoDateHistogram reduced, List<InternalAut
 
                 for (InternalAutoDateHistogram histogram : inputs) {
                     for (Histogram.Bucket bucket : histogram.getBuckets()) {
-                        long roundedBucketKey = roundingInfo.rounding.round(((ZonedDateTime) bucket.getKey()).toInstant().toEpochMilli());
+                        long roundedBucketKey = prepared.round(((ZonedDateTime) bucket.getKey()).toInstant().toEpochMilli());
                         long docCount = bucket.getDocCount();
                         if (roundedBucketKey >= keyForBucket && roundedBucketKey < nextKey) {
                             expectedCounts.compute(key,
@@ -227,8 +228,8 @@ protected void assertReduced(InternalAutoDateHistogram reduced, List<InternalAut
 
             // If there is only a single bucket, and we haven't added it above, add a bucket with no documents.
             // this step is necessary because of the roundedBucketKey < keyForBucket + intervalInMillis above.
-            if (roundingInfo.rounding.round(lowest) == roundingInfo.rounding.round(highest) && expectedCounts.isEmpty()) {
-                expectedCounts.put(Instant.ofEpochMilli(roundingInfo.rounding.round(lowest)), 0L);
+            if (prepared.round(lowest) == prepared.round(highest) && expectedCounts.isEmpty()) {
+                expectedCounts.put(Instant.ofEpochMilli(prepared.round(lowest)), 0L);
             }
         }
 
@@ -249,12 +250,12 @@ protected void assertReduced(InternalAutoDateHistogram reduced, List<InternalAut
         assertThat(reduced.getInterval(), equalTo(expectedInterval));
     }
 
-    private int getBucketCount(long min, long max, Rounding rounding, int interval) {
+    private int getBucketCount(long min, long max, Rounding.Prepared prepared, int interval) {
         int bucketCount = 0;
-        long key = rounding.round(min);
+        long key = prepared.round(min);
         while (key < max) {
             for (int i = 0; i < interval; i++) {
-                key = rounding.nextRoundingValue(key);
+                key = prepared.nextRoundingValue(key);
             }
             bucketCount++;
         }
diff --git a/server/src/test/java/org/elasticsearch/search/aggregations/bucket/histogram/InternalDateHistogramTests.java b/server/src/test/java/org/elasticsearch/search/aggregations/bucket/histogram/InternalDateHistogramTests.java
index 3a4ed0006b47c..d1d402e9d5e98 100644
--- a/server/src/test/java/org/elasticsearch/search/aggregations/bucket/histogram/InternalDateHistogramTests.java
+++ b/server/src/test/java/org/elasticsearch/search/aggregations/bucket/histogram/InternalDateHistogramTests.java
@@ -58,7 +58,8 @@ public void setUp() throws Exception {
         long interval = randomIntBetween(1, 3);
         intervalMillis = randomFrom(timeValueSeconds(interval), timeValueMinutes(interval), timeValueHours(interval)).getMillis();
         Rounding rounding = Rounding.builder(TimeValue.timeValueMillis(intervalMillis)).build();
-        baseMillis = rounding.round(System.currentTimeMillis());
+        long now = System.currentTimeMillis();
+        baseMillis = rounding.prepare(now, now).round(now);
         if (randomBoolean()) {
             minDocCount = randomIntBetween(1, 10);
             emptyBucketInfo = null;
@@ -108,8 +109,12 @@ protected void assertReduced(InternalDateHistogram reduced, List<InternalDateHis
             long minBound = -1;
             long maxBound = -1;
             if (emptyBucketInfo.bounds != null) {
-                minBound = emptyBucketInfo.rounding.round(emptyBucketInfo.bounds.getMin());
-                maxBound = emptyBucketInfo.rounding.round(emptyBucketInfo.bounds.getMax());
+                Rounding.Prepared prepared = emptyBucketInfo.rounding.prepare(
+                    emptyBucketInfo.bounds.getMin(),
+                    emptyBucketInfo.bounds.getMax()
+                );
+                minBound = prepared.round(emptyBucketInfo.bounds.getMin());
+                maxBound = prepared.round(emptyBucketInfo.bounds.getMax());
                 if (expectedCounts.isEmpty() && minBound <= maxBound) {
                     expectedCounts.put(minBound, 0L);
                 }
diff --git a/x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/rollup/job/DateHistogramGroupConfig.java b/x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/rollup/job/DateHistogramGroupConfig.java
index 4db5966671df4..e8f67c8ac3932 100644
--- a/x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/rollup/job/DateHistogramGroupConfig.java
+++ b/x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/rollup/job/DateHistogramGroupConfig.java
@@ -304,7 +304,7 @@ public String getTimeZone() {
     /**
      * Create the rounding for this date histogram
      */
-    public Rounding createRounding() {
+    public Rounding.Prepared createRounding() {
         return createRounding(interval.toString(), timeZone);
     }
 
@@ -363,7 +363,7 @@ public static DateHistogramGroupConfig fromXContent(final XContentParser parser)
         return PARSER.parse(parser, null);
     }
 
-    private static Rounding createRounding(final String expr, final String timeZone) {
+    private static Rounding.Prepared createRounding(final String expr, final String timeZone) {
         Rounding.DateTimeUnit timeUnit = DateHistogramAggregationBuilder.DATE_FIELD_UNITS.get(expr);
         final Rounding.Builder rounding;
         if (timeUnit != null) {
@@ -372,6 +372,6 @@ private static Rounding createRounding(final String expr, final String timeZone)
             rounding = new Rounding.Builder(TimeValue.parseTimeValue(expr, "createRounding"));
         }
         rounding.timeZone(ZoneId.of(timeZone, ZoneId.SHORT_IDS));
-        return rounding.build();
+        return rounding.build().prepareForUnknown();
     }
 }
diff --git a/x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/transform/transforms/pivot/DateHistogramGroupSource.java b/x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/transform/transforms/pivot/DateHistogramGroupSource.java
index f61497e31d3e6..08277310e76a8 100644
--- a/x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/transform/transforms/pivot/DateHistogramGroupSource.java
+++ b/x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/transform/transforms/pivot/DateHistogramGroupSource.java
@@ -209,13 +209,27 @@ private void writeInterval(Interval interval, StreamOutput out) throws IOExcepti
 
     private final Interval interval;
     private final ZoneId timeZone;
-    private Rounding rounding;
+    private final Rounding.Prepared rounding;
 
     public DateHistogramGroupSource(String field, ScriptConfig scriptConfig, Interval interval, ZoneId timeZone) {
         super(field, scriptConfig);
         this.interval = interval;
         this.timeZone = timeZone;
+        rounding = buildRounding();
+    }
+
+    public DateHistogramGroupSource(StreamInput in) throws IOException {
+        super(in);
+        this.interval = readInterval(in);
+        this.timeZone = in.readOptionalZoneId();
+        // Format was optional in 7.2.x, removed in 7.3+
+        if (in.getVersion().before(Version.V_7_3_0)) {
+            in.readOptionalString();
+        }
+        rounding = buildRounding();
+    }
 
+    private Rounding.Prepared buildRounding() {
         Rounding.DateTimeUnit timeUnit = DateHistogramAggregationBuilder.DATE_FIELD_UNITS.get(interval.toString());
         final Rounding.Builder roundingBuilder;
         if (timeUnit != null) {
@@ -227,17 +241,7 @@ public DateHistogramGroupSource(String field, ScriptConfig scriptConfig, Interva
         if (timeZone != null) {
             roundingBuilder.timeZone(timeZone);
         }
-        this.rounding = roundingBuilder.build();
-    }
-
-    public DateHistogramGroupSource(StreamInput in) throws IOException {
-        super(in);
-        this.interval = readInterval(in);
-        this.timeZone = in.readOptionalZoneId();
-        // Format was optional in 7.2.x, removed in 7.3+
-        if (in.getVersion().before(Version.V_7_3_0)) {
-            in.readOptionalString();
-        }
+        return roundingBuilder.build().prepareForUnknown();
     }
 
     private static ConstructingObjectParser<DateHistogramGroupSource, Void> createParser(boolean lenient) {
@@ -296,7 +300,7 @@ public ZoneId getTimeZone() {
         return timeZone;
     }
 
-    public Rounding getRounding() {
+    Rounding.Prepared getRounding() {
         return rounding;
     }
 
diff --git a/x-pack/plugin/rollup/src/test/java/org/elasticsearch/xpack/rollup/job/RollupIndexerIndexingTests.java b/x-pack/plugin/rollup/src/test/java/org/elasticsearch/xpack/rollup/job/RollupIndexerIndexingTests.java
index 8ab5b68b7ae7c..673c49122bc12 100644
--- a/x-pack/plugin/rollup/src/test/java/org/elasticsearch/xpack/rollup/job/RollupIndexerIndexingTests.java
+++ b/x-pack/plugin/rollup/src/test/java/org/elasticsearch/xpack/rollup/job/RollupIndexerIndexingTests.java
@@ -283,7 +283,7 @@ public void testSimpleDateHistoWithDelay() throws Exception {
                         asMap("the_histo", now)
                 )
         );
-        final Rounding rounding = dateHistoConfig.createRounding();
+        final Rounding.Prepared rounding = dateHistoConfig.createRounding();
         executeTestCase(dataset, job, now, (resp) -> {
             assertThat(resp.size(), equalTo(3));
             IndexRequest request = resp.get(0);
@@ -350,7 +350,7 @@ public void testSimpleDateHistoWithOverlappingDelay() throws Exception {
                 asMap("the_histo", now)
             )
         );
-        final Rounding rounding = dateHistoConfig.createRounding();
+        final Rounding.Prepared rounding = dateHistoConfig.createRounding();
         executeTestCase(dataset, job, now, (resp) -> {
             assertThat(resp.size(), equalTo(2));
             IndexRequest request = resp.get(0);