diff --git a/promql/engine.go b/promql/engine.go
index 83e44e61f9..fb4e65a84e 100644
--- a/promql/engine.go
+++ b/promql/engine.go
@@ -685,6 +685,9 @@ func durationMilliseconds(d time.Duration) int64 {
 func (ng *Engine) execEvalStmt(ctx context.Context, query *query, s *parser.EvalStmt) (parser.Value, annotations.Annotations, error) {
 	prepareSpanTimer, ctxPrepare := query.stats.GetSpanTimer(ctx, stats.QueryPreparationTime, ng.metrics.queryPrepareTime)
 	mint, maxt := FindMinMaxTime(s)
+	// metric[5m] + metric[5m] offset 5m
+	// mint -10m (-5m - 5m offset)
+	// maxt now()
 	querier, err := query.queryable.Querier(mint, maxt)
 	if err != nil {
 		prepareSpanTimer.Finish()
@@ -2171,6 +2174,15 @@ func (ev *evaluator) matrixSelector(node *parser.MatrixSelector) (Matrix, annota
 
 		it = storage.NewBuffer(durationMilliseconds(node.Range))
 	)
+
+	// TODO Test for case where range of 1ms
+	if node.OpenLeft {
+		mint += 1
+	}
+	if node.OpenRight {
+		maxt -= 1
+	}
+
 	ws, err := checkAndExpandSeriesSet(ev.ctx, node)
 	if err != nil {
 		ev.error(errWithWarnings{fmt.Errorf("expanding series: %w", err), ws})
diff --git a/promql/functions.go b/promql/functions.go
index 9b3be22874..fa94bf6ef9 100644
--- a/promql/functions.go
+++ b/promql/functions.go
@@ -73,7 +73,7 @@ func extrapolatedRate(vals []parser.Value, args parser.Expressions, enh *EvalNod
 	var (
 		samples            = vals[0].(Matrix)[0]
 		rangeStart         = enh.Ts - durationMilliseconds(ms.Range+vs.Offset)
-		rangeEnd           = enh.Ts - durationMilliseconds(vs.Offset)
+		rangeEnd           = enh.Ts - durationMilliseconds(vs.Offset) // TODO Open this in the vector selector
 		resultFloat        float64
 		resultHistogram    *histogram.FloatHistogram
 		firstT, lastT      int64
diff --git a/promql/parser/ast.go b/promql/parser/ast.go
index 830e8a2c5e..3e7e49288c 100644
--- a/promql/parser/ast.go
+++ b/promql/parser/ast.go
@@ -126,6 +126,9 @@ type MatrixSelector struct {
 	VectorSelector Expr
 	Range          time.Duration
 
+	OpenLeft  bool
+	OpenRight bool
+
 	EndPos posrange.Pos
 }
 
diff --git a/promql/parser/generated_parser.y b/promql/parser/generated_parser.y
index 841bd31c19..c04f32f2b8 100644
--- a/promql/parser/generated_parser.y
+++ b/promql/parser/generated_parser.y
@@ -28,22 +28,23 @@ import (
 %}
 
 %union {
-    node        Node
-    item        Item
-    matchers    []*labels.Matcher
-    matcher     *labels.Matcher
-    label       labels.Label
-    labels      labels.Labels
-    lblList     []labels.Label
-    strings     []string
-    series      []SequenceValue
-    histogram   *histogram.FloatHistogram
-    descriptors map[string]interface{}
-    bucket_set  []float64
-    int         int64
-    uint        uint64
-    float       float64
-    duration    time.Duration
+    node           Node
+    item           Item
+    matchers       []*labels.Matcher
+    matcher        *labels.Matcher
+    label          labels.Label
+    labels         labels.Labels
+    lblList        []labels.Label
+    strings        []string
+    series         []SequenceValue
+    histogram      *histogram.FloatHistogram
+    descriptors    map[string]interface{}
+    bucket_set     []float64
+    int            int64
+    uint           uint64
+    float          float64
+    duration       time.Duration
+    range_duration rangeDuration
 }
 
 
@@ -449,7 +450,7 @@ at_modifier_preprocessors: START | END;
  * Subquery and range selectors.
  */
 
-matrix_selector : expr LEFT_BRACKET duration RIGHT_BRACKET
+matrix_selector : expr LEFT_BRACKET range_duration RIGHT_BRACKET
                         {
                         var errMsg string
                         vs, ok := $1.(*VectorSelector)
@@ -468,7 +469,9 @@ matrix_selector : expr LEFT_BRACKET duration RIGHT_BRACKET
 
                         $$ = &MatrixSelector{
                                 VectorSelector: $1.(Expr),
-                                Range: $3,
+                                Range: $3.duration,
+                                OpenLeft: $3.openLeft,
+                                OpenRight: $3.openRight,
                                 EndPos: yylex.(*parser).lastClosing,
                         }
                         }
@@ -899,6 +902,47 @@ duration        : DURATION
                         }
                 ;
 
+range_duration :  DURATION
+			{
+			var err error
+			$$.duration, err = parseDuration($1.Val)
+			if err != nil {
+				yylex.(*parser).addParseErr($1.PositionRange(), err)
+			}
+			}
+		| POW DURATION
+			{
+			var err error
+			$$.duration, err = parseDuration($1.Val)
+			if err != nil {
+				yylex.(*parser).addParseErr($1.PositionRange(), err)
+			}
+
+			$$.openLeft = true
+			}
+		| DURATION POW
+			{
+			var err error
+			$$.duration, err = parseDuration($1.Val)
+			if err != nil {
+				yylex.(*parser).addParseErr($1.PositionRange(), err)
+			}
+
+			$$.openRight = true
+			}
+		| POW DURATION POW
+			{
+			var err error
+			$$.duration, err = parseDuration($1.Val)
+			if err != nil {
+				yylex.(*parser).addParseErr($1.PositionRange(), err)
+			}
+
+			$$.openLeft = true
+			$$.openRight = true
+			}
+		;
+
 
 string_literal  : STRING
                         {
diff --git a/promql/parser/lex.go b/promql/parser/lex.go
index 4e3de2a668..cf5719c860 100644
--- a/promql/parser/lex.go
+++ b/promql/parser/lex.go
@@ -16,6 +16,7 @@ package parser
 import (
 	"fmt"
 	"strings"
+	"time"
 	"unicode"
 	"unicode/utf8"
 
@@ -1000,3 +1001,9 @@ func isLabel(s string) bool {
 	}
 	return true
 }
+
+type rangeDuration struct {
+	duration  time.Duration
+	openLeft  bool
+	openRight bool
+}