diff --git a/Makefile b/Makefile
index f5b6fa0bebb..e7db2762a39 100644
--- a/Makefile
+++ b/Makefile
@@ -24,7 +24,7 @@ endif
 GO = go
 GOTEST_MIN = go test -v -timeout 30s
 GOTEST = $(GOTEST_MIN) -race
-GOTEST_WITH_COVERAGE = $(GOTEST) -coverprofile=coverage.out -covermode=atomic -coverpkg=./...
+GOTEST_WITH_COVERAGE = $(GOTEST) -coverprofile=coverage.out -covermode=atomic -coverpkg=go.opentelemetry.io/contrib/...
 
 .DEFAULT_GOAL := precommit
 
@@ -40,6 +40,10 @@ $(TOOLS_DIR)/misspell: $(TOOLS_MOD_DIR)/go.mod $(TOOLS_MOD_DIR)/go.sum $(TOOLS_M
 	cd $(TOOLS_MOD_DIR) && \
 	go build -o $(TOOLS_DIR)/misspell github.com/client9/misspell/cmd/misspell
 
+$(TOOLS_DIR)/gocovmerge: $(TOOLS_MOD_DIR)/go.mod $(TOOLS_MOD_DIR)/go.sum $(TOOLS_MOD_DIR)/tools.go
+	cd $(TOOLS_MOD_DIR) && \
+	go build -o $(TOOLS_DIR)/gocovmerge github.com/wadey/gocovmerge
+
 $(TOOLS_DIR)/stringer: $(TOOLS_MOD_DIR)/go.mod $(TOOLS_MOD_DIR)/go.sum $(TOOLS_MOD_DIR)/tools.go
 	cd $(TOOLS_MOD_DIR) && \
 	go build -o $(TOOLS_DIR)/stringer golang.org/x/tools/cmd/stringer
@@ -47,7 +51,7 @@ $(TOOLS_DIR)/stringer: $(TOOLS_MOD_DIR)/go.mod $(TOOLS_MOD_DIR)/go.sum $(TOOLS_M
 precommit: dependabot-check license-check generate lint build test
 
 .PHONY: test-with-coverage
-test-with-coverage:
+test-with-coverage: $(TOOLS_DIR)/gocovmerge
 	set -e; \
 	printf "" > coverage.txt; \
 	for dir in $(ALL_COVERAGE_MOD_DIRS); do \
@@ -55,9 +59,8 @@ test-with-coverage:
 	  (cd "$${dir}" && \
 	    $(GOTEST_WITH_COVERAGE) ./... && \
 	    go tool cover -html=coverage.out -o coverage.html); \
-	  [ -f "$${dir}/coverage.out" ] && cat "$${dir}/coverage.out" >> coverage.txt; \
 	done; \
-	sed -i.bak -e '2,$$ { /^mode: /d; }' coverage.txt && rm coverage.txt.bak
+	$(TOOLS_DIR)/gocovmerge $$(find . -name coverage.out) > coverage.txt
 
 .PHONY: ci
 ci: precommit check-clean-work-tree test-with-coverage test-386
diff --git a/tools/go.mod b/tools/go.mod
index 9266dda7f87..9c2ee54246a 100644
--- a/tools/go.mod
+++ b/tools/go.mod
@@ -5,5 +5,6 @@ go 1.13
 require (
 	github.com/client9/misspell v0.3.4
 	github.com/golangci/golangci-lint v1.41.1
+	github.com/wadey/gocovmerge v0.0.0-20160331181800-b5bfa59ec0ad
 	golang.org/x/tools v0.1.5
 )
diff --git a/tools/go.sum b/tools/go.sum
index 59b5e358281..81751ce1504 100644
--- a/tools/go.sum
+++ b/tools/go.sum
@@ -638,6 +638,8 @@ github.com/valyala/fasthttp v1.16.0/go.mod h1:YOKImeEosDdBPnxc0gy7INqi3m1zK6A+xl
 github.com/valyala/quicktemplate v1.6.3/go.mod h1:fwPzK2fHuYEODzJ9pkw0ipCPNHZ2tD5KW4lOuSdPKzY=
 github.com/valyala/tcplisten v0.0.0-20161114210144-ceec8f93295a/go.mod h1:v3UYOV9WzVtRmSR+PDvWpU/qWl4Wa5LApYYX4ZtKbio=
 github.com/viki-org/dnscache v0.0.0-20130720023526-c70c1f23c5d8/go.mod h1:dniwbG03GafCjFohMDmz6Zc6oCuiqgH6tGNyXTkHzXE=
+github.com/wadey/gocovmerge v0.0.0-20160331181800-b5bfa59ec0ad h1:W0LEBv82YCGEtcmPA3uNZBI33/qF//HAAs3MawDjRa0=
+github.com/wadey/gocovmerge v0.0.0-20160331181800-b5bfa59ec0ad/go.mod h1:Hy8o65+MXnS6EwGElrSRjUzQDLXreJlzYLlWiHtt8hM=
 github.com/xiang90/probing v0.0.0-20190116061207-43a291ad63a2/go.mod h1:UETIi67q53MR2AWcXfiuqkDkRtnGDLqkBTpCHuJHxtU=
 github.com/xo/terminfo v0.0.0-20210125001918-ca9a967f8778/go.mod h1:2MuV+tbUrU1zIOPMxZ5EncGwgmMJsa+9ucAQZXxsObs=
 github.com/xordataexchange/crypt v0.0.3-0.20170626215501-b2862e3d0a77/go.mod h1:aYKd//L2LvnjZzWKhF00oedf4jCCReLcmhLdhm1A27Q=
diff --git a/tools/tools.go b/tools/tools.go
index f449e286803..329b108a76a 100644
--- a/tools/tools.go
+++ b/tools/tools.go
@@ -19,5 +19,6 @@ package tools
 import (
 	_ "github.com/client9/misspell/cmd/misspell"
 	_ "github.com/golangci/golangci-lint/cmd/golangci-lint"
+	_ "github.com/wadey/gocovmerge"
 	_ "golang.org/x/tools/cmd/stringer"
 )