diff --git a/internal/metrics/datum/buckets.go b/internal/metrics/datum/buckets.go
index 4d4a11736..ef15f0cb0 100644
--- a/internal/metrics/datum/buckets.go
+++ b/internal/metrics/datum/buckets.go
@@ -44,7 +44,7 @@ func (d *Buckets) Observe(v float64, ts time.Time) {
 	defer d.Unlock()
 
 	for i, b := range d.Buckets {
-		if b.Range.Contains(v) {
+		if v <= b.Range.Max {
 			d.Buckets[i].Count++
 			break
 		}
diff --git a/internal/runtime/compiler/codegen/codegen.go b/internal/runtime/compiler/codegen/codegen.go
index e18a05a4d..30467b796 100644
--- a/internal/runtime/compiler/codegen/codegen.go
+++ b/internal/runtime/compiler/codegen/codegen.go
@@ -130,17 +130,12 @@ func (c *codegen) VisitBefore(node ast.Node) (ast.Visitor, ast.Node) {
 				c.errorf(n.Pos(), "a histogram need at least two boundaries")
 				return nil, n
 			}
-			if n.Buckets[0] >= n.Buckets[1] {
-				c.errorf(n.Pos(), "buckets boundaries must be sorted")
-				return nil, n
-			}
 
 			if n.Buckets[0] > 0 {
 				m.Buckets = append(m.Buckets, datum.Range{0, n.Buckets[0]})
 			}
-			m.Buckets = append(m.Buckets, datum.Range{n.Buckets[0], n.Buckets[1]})
-			min := n.Buckets[1]
-			for _, max := range n.Buckets[2:] {
+			min := n.Buckets[0]
+			for _, max := range n.Buckets[1:] {
 				if max <= min {
 					c.errorf(n.Pos(), "buckets boundaries must be sorted")
 					return nil, n
diff --git a/internal/runtime/runtime_integration_test.go b/internal/runtime/runtime_integration_test.go
index 883c832a5..f5b8b28b2 100644
--- a/internal/runtime/runtime_integration_test.go
+++ b/internal/runtime/runtime_integration_test.go
@@ -71,6 +71,7 @@ histogram hist3 by f buckets -1, 0, 1
 		`b 3
 b 3
 b 3
+b 0
 `,
 		0,
 		metrics.MetricSlice{
@@ -84,7 +85,10 @@ b 3
 					{
 						Value: &datum.Buckets{
 							Buckets: []datum.BucketCount{
-								{Range: datum.Range{Min: 0, Max: 1}},
+								{
+									Range: datum.Range{Min: 0, Max: 1},
+									Count: 1,
+								},
 								{Range: datum.Range{Min: 1, Max: 2}},
 								{
 									Range: datum.Range{Min: 2, Max: 4},
@@ -93,7 +97,7 @@ b 3
 								{Range: datum.Range{Min: 4, Max: 8}},
 								{Range: datum.Range{Min: 8, Max: math.Inf(+1)}},
 							},
-							Count: 3,
+							Count: 4,
 							Sum:   9,
 						},
 					},
@@ -111,7 +115,10 @@ b 3
 						Labels: []string{"b"},
 						Value: &datum.Buckets{
 							Buckets: []datum.BucketCount{
-								{Range: datum.Range{Min: 0, Max: 1}},
+								{
+									Range: datum.Range{Min: 0, Max: 1},
+									Count: 1,
+								},
 								{Range: datum.Range{Min: 1, Max: 2}},
 								{
 									Range: datum.Range{Min: 2, Max: 4},
@@ -120,7 +127,7 @@ b 3
 								{Range: datum.Range{Min: 4, Max: 8}},
 								{Range: datum.Range{Min: 8, Max: math.Inf(+1)}},
 							},
-							Count: 3,
+							Count: 4,
 							Sum:   9,
 						},
 					},
@@ -139,14 +146,17 @@ b 3
 						Labels: []string{"b"},
 						Value: &datum.Buckets{
 							Buckets: []datum.BucketCount{
-								{Range: datum.Range{Min: -1, Max: 0}},
+								{
+									Range: datum.Range{Min: -1, Max: 0},
+									Count: 1,
+								},
 								{Range: datum.Range{Min: 0, Max: 1}},
 								{
 									Range: datum.Range{Min: 1, Max: math.Inf(+1)},
 									Count: 3,
 								},
 							},
-							Count: 3,
+							Count: 4,
 							Sum:   9,
 						},
 					},