diff --git a/CHANGELOG.md b/CHANGELOG.md
index 999630aa2a31..a9d5366e766e 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,6 +1,7 @@
 ## Main
 
 * [5302](https://github.com/grafana/loki/pull/5302) **MasslessParticle** Update azure blobstore client to use new sdk.
+* [5243](https://github.com/grafana/loki/pull/5290) **ssncferreira**: Update Promtail to support duration string formats.
 * [5266](https://github.com/grafana/loki/pull/5266) **jeschkies**: Write Promtail position file atomically on Unix.
 * [5280](https://github.com/grafana/loki/pull/5280) **jeschkies**: Fix Docker target connection loss.
 * [5243](https://github.com/grafana/loki/pull/5243) **owen-d**: moves `querier.split-queries-by-interval` to limits code only.
diff --git a/clients/pkg/logentry/stages/metrics.go b/clients/pkg/logentry/stages/metrics.go
index 2079dadfdaed..4626485bba4d 100644
--- a/clients/pkg/logentry/stages/metrics.go
+++ b/clients/pkg/logentry/stages/metrics.go
@@ -311,7 +311,7 @@ func getFloat(unk interface{}) (float64, error) {
 	case uint:
 		return float64(i), nil
 	case string:
-		return strconv.ParseFloat(i, 64)
+		return getFloatFromString(i)
 	case bool:
 		if i {
 			return float64(1), nil
@@ -321,3 +321,22 @@ func getFloat(unk interface{}) (float64, error) {
 		return math.NaN(), fmt.Errorf("can't convert %v to float64", unk)
 	}
 }
+
+// getFloatFromString converts string into float64
+// Two types of string formats are supported:
+//   * strings that represent floating point numbers, e.g., "0.804"
+//   * duration format strings, e.g., "0.5ms", "10h".
+//     Valid time units are "ns", "us", "ms", "s", "m", "h".
+//     Values in this format are converted as a floating point number of seconds.
+//     E.g., "0.5ms" is converted to 0.0005
+func getFloatFromString(str string) (float64, error) {
+	dur, err := strconv.ParseFloat(str, 64)
+	if err != nil {
+		dur, err := time.ParseDuration(str)
+		if err != nil {
+			return 0, err
+		}
+		return dur.Seconds(), nil
+	}
+	return dur, nil
+}
diff --git a/clients/pkg/logentry/stages/metrics_test.go b/clients/pkg/logentry/stages/metrics_test.go
index c5ed7915273e..dd151a9549b2 100644
--- a/clients/pkg/logentry/stages/metrics_test.go
+++ b/clients/pkg/logentry/stages/metrics_test.go
@@ -321,8 +321,9 @@ func TestMetricStage_Process(t *testing.T) {
 			"contains_false":  "contains(keys(@),'nope')",
 		},
 	}
+	regexHTTPFixture := `11.11.11.11 - frank [25/Jan/2000:14:00:01 -0500] "GET /1986.js HTTP/1.1" 200 932ms"`
 	regexConfig := map[string]interface{}{
-		"expression": "(?P<get>\"GET).*HTTP/1.1\" (?P<status>\\d*) (?P<time>\\d*) ",
+		"expression": "(?P<get>\"GET).*HTTP/1.1\" (?P<status>\\d*) (?P<time>\\d*ms)",
 	}
 	timeSource := "time"
 	true := "true"
@@ -386,12 +387,12 @@ func TestMetricStage_Process(t *testing.T) {
 				Action: metric.CounterInc,
 			},
 		},
-		"response_time_ms": MetricConfig{
+		"response_time_seconds": MetricConfig{
 			MetricType:  "Histogram",
 			Source:      &timeSource,
 			Description: "response time in ms",
 			Config: metric.HistogramConfig{
-				Buckets: []float64{1, 2, 3},
+				Buckets: []float64{0.5, 1, 2},
 			},
 		},
 	}
@@ -410,7 +411,7 @@ func TestMetricStage_Process(t *testing.T) {
 		t.Fatalf("failed to create stage with metrics: %v", err)
 	}
 	out := processEntries(jsonStage, newEntry(nil, labelFoo, logFixture, time.Now()))
-	out[0].Line = regexLogFixture
+	out[0].Line = regexHTTPFixture
 	out = processEntries(regexStage, out...)
 	out = processEntries(metricStage, out...)
 	out[0].Labels = labelFu
@@ -473,20 +474,20 @@ promtail_custom_numeric_integer{baz="fu",fu="baz"} 123.0
 # TYPE promtail_custom_numeric_string gauge
 promtail_custom_numeric_string{bar="foo",foo="bar"} 123.0
 promtail_custom_numeric_string{baz="fu",fu="baz"} 123.0
-# HELP promtail_custom_response_time_ms response time in ms
-# TYPE promtail_custom_response_time_ms histogram
-promtail_custom_response_time_ms_bucket{bar="foo",foo="bar",le="1.0"} 0.0
-promtail_custom_response_time_ms_bucket{bar="foo",foo="bar",le="2.0"} 0.0
-promtail_custom_response_time_ms_bucket{bar="foo",foo="bar",le="3.0"} 0.0
-promtail_custom_response_time_ms_bucket{bar="foo",foo="bar",le="+Inf"} 1.0
-promtail_custom_response_time_ms_sum{bar="foo",foo="bar"} 932.0
-promtail_custom_response_time_ms_count{bar="foo",foo="bar"} 1.0
-promtail_custom_response_time_ms_bucket{baz="fu",fu="baz",le="1.0"} 0.0
-promtail_custom_response_time_ms_bucket{baz="fu",fu="baz",le="2.0"} 0.0
-promtail_custom_response_time_ms_bucket{baz="fu",fu="baz",le="3.0"} 0.0
-promtail_custom_response_time_ms_bucket{baz="fu",fu="baz",le="+Inf"} 1.0
-promtail_custom_response_time_ms_sum{baz="fu",fu="baz"} 932.0
-promtail_custom_response_time_ms_count{baz="fu",fu="baz"} 1.0
+# HELP promtail_custom_response_time_seconds response time in ms
+# TYPE promtail_custom_response_time_seconds histogram
+promtail_custom_response_time_seconds_bucket{bar="foo",foo="bar",le="0.5"} 0
+promtail_custom_response_time_seconds_bucket{bar="foo",foo="bar",le="1"} 1
+promtail_custom_response_time_seconds_bucket{bar="foo",foo="bar",le="2"} 1
+promtail_custom_response_time_seconds_bucket{bar="foo",foo="bar",le="+Inf"} 1
+promtail_custom_response_time_seconds_sum{bar="foo",foo="bar"} 0.932
+promtail_custom_response_time_seconds_count{bar="foo",foo="bar"} 1
+promtail_custom_response_time_seconds_bucket{baz="fu",fu="baz",le="0.5"} 0
+promtail_custom_response_time_seconds_bucket{baz="fu",fu="baz",le="1"} 1
+promtail_custom_response_time_seconds_bucket{baz="fu",fu="baz",le="2"} 1
+promtail_custom_response_time_seconds_bucket{baz="fu",fu="baz",le="+Inf"} 1
+promtail_custom_response_time_seconds_sum{baz="fu",fu="baz"} 0.932
+promtail_custom_response_time_seconds_count{baz="fu",fu="baz"} 1.0
 # HELP promtail_custom_total_keys the total keys per doc
 # TYPE promtail_custom_total_keys counter
 promtail_custom_total_keys{bar="foo",foo="bar"} 8.0
diff --git a/docs/sources/clients/promtail/stages/metrics.md b/docs/sources/clients/promtail/stages/metrics.md
index 4ff1f1eed228..f80e7e3046ad 100644
--- a/docs/sources/clients/promtail/stages/metrics.md
+++ b/docs/sources/clients/promtail/stages/metrics.md
@@ -274,3 +274,16 @@ number in the `retries` field from the extracted map.
 This pipeline creates a histogram that reads `response_time` from the extracted
 map and places it into a bucket, both increasing the count of the bucket and the
 sum for that particular bucket.
+
+## Supported values
+
+The metric values extracted from the log data are internally converted to floating points. 
+The supported values are the following:
+* integers, floating point numbers
+* string - two types of string formats are supported:
+  * strings that represent floating point numbers: e.g., `"0.804"` is converted to `0.804`.
+  * duration format strings. Valid time units are "ns", "us", "ms", "s", "m", "h". 
+    Values in this format are converted as a floating point number of seconds. E.g., `"0.5ms"` is converted to `0.0005`.
+* boolean:
+  * `true` is converted to `1`
+  * `false` is converted to `0`
\ No newline at end of file