diff --git a/scrape/scrape.go b/scrape/scrape.go
index 215c63c0497..d9ed8a02b7c 100644
--- a/scrape/scrape.go
+++ b/scrape/scrape.go
@@ -24,6 +24,7 @@ import (
 	"math"
 	"net/http"
 	"reflect"
+	"strconv"
 	"sync"
 	"time"
 	"unsafe"
@@ -718,7 +719,7 @@ func (s *targetScraper) scrape(ctx context.Context, w io.Writer) (string, error)
 		req.Header.Add("Accept", acceptHeader)
 		req.Header.Add("Accept-Encoding", "gzip")
 		req.Header.Set("User-Agent", userAgentHeader)
-		req.Header.Set("X-Prometheus-Scrape-Timeout-Seconds", fmt.Sprintf("%f", s.timeout.Seconds()))
+		req.Header.Set("X-Prometheus-Scrape-Timeout-Seconds", strconv.FormatFloat(s.timeout.Seconds(), 'f', -1, 64))
 
 		s.req = req
 	}
diff --git a/scrape/scrape_test.go b/scrape/scrape_test.go
index 5848c5cb112..56109d4e2d8 100644
--- a/scrape/scrape_test.go
+++ b/scrape/scrape_test.go
@@ -1825,7 +1825,7 @@ func TestScrapeLoopOutOfBoundsTimeError(t *testing.T) {
 func TestTargetScraperScrapeOK(t *testing.T) {
 	const (
 		configTimeout   = 1500 * time.Millisecond
-		expectedTimeout = "1.500000"
+		expectedTimeout = "1.5"
 	)
 
 	server := httptest.NewServer(