diff --git a/promql/engine.go b/promql/engine.go
index 13f8b06972..a23e899d04 100644
--- a/promql/engine.go
+++ b/promql/engine.go
@@ -1352,7 +1352,7 @@ func (ev *evaluator) rangeEvalAgg(ctx context.Context, aggExpr *parser.Aggregate
 	}
 	groups := make([]groupedAggregation, groupCount)
 
-	var k int
+	var k int64
 	var ratio float64
 	var seriess map[uint64]Series
 	switch aggExpr.Op {
@@ -1360,9 +1360,9 @@ func (ev *evaluator) rangeEvalAgg(ctx context.Context, aggExpr *parser.Aggregate
 		if !convertibleToInt64(param) {
 			ev.errorf("Scalar value %v overflows int64", param)
 		}
-		k = int(param)
-		if k > len(inputMatrix) {
-			k = len(inputMatrix)
+		k = int64(param)
+		if k > int64(len(inputMatrix)) {
+			k = int64(len(inputMatrix))
 		}
 		if k < 1 {
 			return nil, warnings
@@ -3172,7 +3172,7 @@ func (ev *evaluator) aggregation(e *parser.AggregateExpr, q float64, inputMatrix
 // seriesToResult maps inputMatrix indexes to groups indexes.
 // For an instant query, returns a Matrix in descending order for topk or ascending for bottomk, or without any order for limitk / limit_ratio.
 // For a range query, aggregates output in the seriess map.
-func (ev *evaluator) aggregationK(e *parser.AggregateExpr, k int, r float64, inputMatrix Matrix, seriesToResult []int, groups []groupedAggregation, enh *EvalNodeHelper, seriess map[uint64]Series) (Matrix, annotations.Annotations) {
+func (ev *evaluator) aggregationK(e *parser.AggregateExpr, k int64, r float64, inputMatrix Matrix, seriesToResult []int, groups []groupedAggregation, enh *EvalNodeHelper, seriess map[uint64]Series) (Matrix, annotations.Annotations) {
 	op := e.Op
 	var s Sample
 	var annos annotations.Annotations
@@ -3243,7 +3243,7 @@ seriesLoop:
 			case s.H != nil:
 				// Ignore histogram sample and add info annotation.
 				annos.Add(annotations.NewHistogramIgnoredInAggregationInfo("topk", e.PosRange))
-			case len(group.heap) < k:
+			case int64(len(group.heap)) < k:
 				heap.Push(&group.heap, &s)
 			case group.heap[0].F < s.F || (math.IsNaN(group.heap[0].F) && !math.IsNaN(s.F)):
 				// This new element is bigger than the previous smallest element - overwrite that.
@@ -3259,7 +3259,7 @@ seriesLoop:
 			case s.H != nil:
 				// Ignore histogram sample and add info annotation.
 				annos.Add(annotations.NewHistogramIgnoredInAggregationInfo("bottomk", e.PosRange))
-			case len(group.heap) < k:
+			case int64(len(group.heap)) < k:
 				heap.Push((*vectorByReverseValueHeap)(&group.heap), &s)
 			case group.heap[0].F > s.F || (math.IsNaN(group.heap[0].F) && !math.IsNaN(s.F)):
 				// This new element is smaller than the previous biggest element - overwrite that.
@@ -3270,13 +3270,13 @@ seriesLoop:
 			}
 
 		case parser.LIMITK:
-			if len(group.heap) < k {
+			if int64(len(group.heap)) < k {
 				heap.Push(&group.heap, &s)
 			}
 			// LIMITK optimization: early break if we've added K elem to _every_ group,
 			// especially useful for large timeseries where the user is exploring labels via e.g.
 			// limitk(10, my_metric)
-			if !group.groupAggrComplete && len(group.heap) == k {
+			if !group.groupAggrComplete && int64(len(group.heap)) == k {
 				group.groupAggrComplete = true
 				groupsRemaining--
 				if groupsRemaining == 0 {