diff --git a/pkg/cmd/gpg-key/add/add.go b/pkg/cmd/gpg-key/add/add.go
index c5b8c2abe..d50529479 100644
--- a/pkg/cmd/gpg-key/add/add.go
+++ b/pkg/cmd/gpg-key/add/add.go
@@ -7,6 +7,7 @@ import (
 	"net/http"
 	"os"
 
+	"github.com/MakeNowJust/heredoc"
 	"github.com/cli/cli/v2/internal/config"
 	"github.com/cli/cli/v2/pkg/cmdutil"
 	"github.com/cli/cli/v2/pkg/iostreams"
@@ -80,18 +81,30 @@ func runAdd(opts *AddOptions) error {
 
 	err = gpgKeyUpload(httpClient, hostname, keyReader)
 	if err != nil {
-		if errors.Is(err, scopesError) {
-			cs := opts.IO.ColorScheme()
+		cs := opts.IO.ColorScheme()
+		if errors.Is(err, errScopesMissing) {
 			fmt.Fprint(opts.IO.ErrOut, "Error: insufficient OAuth scopes to list GPG keys\n")
 			fmt.Fprintf(opts.IO.ErrOut, "Run the following to grant scopes: %s\n", cs.Bold("gh auth refresh -s write:gpg_key"))
 			return cmdutil.SilentError
 		}
+		if errors.Is(err, errDuplicateKey) {
+			fmt.Fprintf(opts.IO.ErrOut, "%s Error: the key already exists in your account\n", cs.FailureIcon())
+			return cmdutil.SilentError
+		}
+		if errors.Is(err, errWrongFormat) {
+			fmt.Fprint(opts.IO.ErrOut, heredoc.Docf(`
+				%s Error: the GPG key you are trying to upload might not be in ASCII-armored format.
+				Find your GPG key ID with:    %s
+				Then add it to your account:  %s
+			`, cs.FailureIcon(), cs.Bold("gpg --list-keys"), cs.Bold("gpg --armor --export <ID> | gh gpg-key add -")))
+			return cmdutil.SilentError
+		}
 		return err
 	}
 
 	if opts.IO.IsStdoutTTY() {
 		cs := opts.IO.ColorScheme()
-		fmt.Fprintf(opts.IO.ErrOut, "%s GPG key added to your account\n", cs.SuccessIcon())
+		fmt.Fprintf(opts.IO.Out, "%s GPG key added to your account\n", cs.SuccessIcon())
 	}
 	return nil
 }
diff --git a/pkg/cmd/gpg-key/add/add_test.go b/pkg/cmd/gpg-key/add/add_test.go
index bbb7a01da..01261beae 100644
--- a/pkg/cmd/gpg-key/add/add_test.go
+++ b/pkg/cmd/gpg-key/add/add_test.go
@@ -4,6 +4,7 @@ import (
 	"net/http"
 	"testing"
 
+	"github.com/MakeNowJust/heredoc"
 	"github.com/cli/cli/v2/internal/config"
 	"github.com/cli/cli/v2/pkg/httpmock"
 	"github.com/cli/cli/v2/pkg/iostreams"
@@ -11,32 +12,114 @@ import (
 )
 
 func Test_runAdd(t *testing.T) {
-	ios, stdin, stdout, stderr := iostreams.Test()
-	ios.SetStdinTTY(false)
-	ios.SetStdoutTTY(true)
-	ios.SetStderrTTY(true)
+	tests := []struct {
+		name       string
+		stdin      string
+		httpStubs  func(*httpmock.Registry)
+		wantStdout string
+		wantStderr string
+		wantErrMsg string
+		opts       AddOptions
+	}{
+		{
+			name:  "valid key",
+			stdin: "-----BEGIN PGP PUBLIC KEY BLOCK-----",
+			httpStubs: func(reg *httpmock.Registry) {
+				reg.Register(
+					httpmock.REST("POST", "user/gpg_keys"),
+					httpmock.StatusStringResponse(200, ``))
+			},
+			wantStdout: "✓ GPG key added to your account\n",
+			wantStderr: "",
+			wantErrMsg: "",
+			opts:       AddOptions{KeyFile: "-"},
+		},
+		{
+			name:  "binary format fails",
+			stdin: "gCAAAAA7H7MHTZWFLJKD3vP4F7v",
+			httpStubs: func(reg *httpmock.Registry) {
+				reg.Register(
+					httpmock.REST("POST", "user/gpg_keys"),
+					httpmock.StatusStringResponse(422, `{
+						"message": "Validation Failed",
+						"errors": [{
+							"resource": "GpgKey",
+							"code": "custom",
+							"message": "We got an error doing that."
+						}],
+						"documentation_url": "https://docs.github.com/v3/users/gpg_keys"
+					}`),
+				)
+			},
+			wantStdout: "",
+			wantStderr: heredoc.Doc(`
+				X Error: the GPG key you are trying to upload might not be in ASCII-armored format.
+				Find your GPG key ID with:    gpg --list-keys
+				Then add it to your account:  gpg --armor --export <ID> | gh gpg-key add -
+			`),
+			wantErrMsg: "SilentError",
+			opts:       AddOptions{KeyFile: "-"},
+		},
+		{
+			name:  "duplicate key",
+			stdin: "-----BEGIN PGP PUBLIC KEY BLOCK-----",
+			httpStubs: func(reg *httpmock.Registry) {
+				reg.Register(
+					httpmock.REST("POST", "user/gpg_keys"),
+					httpmock.WithHeader(httpmock.StatusStringResponse(422, `{
+						"message": "Validation Failed",
+						"errors": [{
+							"resource": "GpgKey",
+							"code": "custom",
+							"field": "key_id",
+							"message": "key_id already exists"
+						}, {
+							"resource": "GpgKey",
+							"code": "custom",
+							"field": "public_key",
+							"message": "public_key already exists"
+						}],
+						"documentation_url": "https://docs.github.com/v3/users/gpg_keys"
+					}`), "Content-type", "application/json"),
+				)
+			},
+			wantStdout: "",
+			wantStderr: "X Error: the key already exists in your account\n",
+			wantErrMsg: "SilentError",
+			opts:       AddOptions{KeyFile: "-"},
+		},
+	}
 
-	stdin.WriteString("PUBKEY")
+	for _, tt := range tests {
+		ios, stdin, stdout, stderr := iostreams.Test()
+		ios.SetStdinTTY(true)
+		ios.SetStdoutTTY(true)
+		ios.SetStderrTTY(true)
+		stdin.WriteString(tt.stdin)
 
-	tr := httpmock.Registry{}
-	defer tr.Verify(t)
+		reg := &httpmock.Registry{}
 
-	tr.Register(
-		httpmock.REST("POST", "user/gpg_keys"),
-		httpmock.StringResponse(`{}`))
-
-	err := runAdd(&AddOptions{
-		IO: ios,
-		Config: func() (config.Config, error) {
+		tt.opts.IO = ios
+		tt.opts.HTTPClient = func() (*http.Client, error) {
+			return &http.Client{Transport: reg}, nil
+		}
+		if tt.httpStubs != nil {
+			tt.httpStubs(reg)
+		}
+		tt.opts.Config = func() (config.Config, error) {
 			return config.NewBlankConfig(), nil
-		},
-		HTTPClient: func() (*http.Client, error) {
-			return &http.Client{Transport: &tr}, nil
-		},
-		KeyFile: "-",
-	})
-	assert.NoError(t, err)
+		}
 
-	assert.Equal(t, "", stdout.String())
-	assert.Equal(t, "✓ GPG key added to your account\n", stderr.String())
+		t.Run(tt.name, func(t *testing.T) {
+			defer reg.Verify(t)
+			err := runAdd(&tt.opts)
+			if tt.wantErrMsg != "" {
+				assert.Equal(t, tt.wantErrMsg, err.Error())
+			} else {
+				assert.NoError(t, err)
+			}
+			assert.Equal(t, tt.wantStdout, stdout.String())
+			assert.Equal(t, tt.wantStderr, stderr.String())
+		})
+	}
 }
diff --git a/pkg/cmd/gpg-key/add/http.go b/pkg/cmd/gpg-key/add/http.go
index 6d0dbd026..c0f6144aa 100644
--- a/pkg/cmd/gpg-key/add/http.go
+++ b/pkg/cmd/gpg-key/add/http.go
@@ -11,7 +11,9 @@ import (
 	"github.com/cli/cli/v2/internal/ghinstance"
 )
 
-var scopesError = errors.New("insufficient OAuth scopes")
+var errScopesMissing = errors.New("insufficient OAuth scopes")
+var errDuplicateKey = errors.New("key already exists")
+var errWrongFormat = errors.New("key in wrong format")
 
 func gpgKeyUpload(httpClient *http.Client, hostname string, keyFile io.Reader) error {
 	url := ghinstance.RESTPrefix(hostname) + "user/gpg_keys"
@@ -42,25 +44,27 @@ func gpgKeyUpload(httpClient *http.Client, hostname string, keyFile io.Reader) e
 	defer resp.Body.Close()
 
 	if resp.StatusCode == 404 {
-		return scopesError
+		return errScopesMissing
 	} else if resp.StatusCode > 299 {
-		var httpError api.HTTPError
 		err := api.HandleHTTPError(resp)
-		if errors.As(err, &httpError) && isDuplicateError(&httpError) {
-			return nil
+		var httpError api.HTTPError
+		if errors.As(err, &httpError) {
+			for _, e := range httpError.Errors {
+				if resp.StatusCode == 422 && e.Field == "key_id" && e.Message == "key_id already exists" {
+					return errDuplicateKey
+				}
+			}
+		}
+		if resp.StatusCode == 422 && !isGpgKeyArmored(keyBytes) {
+			return errWrongFormat
 		}
 		return err
 	}
 
-	_, err = io.Copy(io.Discard, resp.Body)
-	if err != nil {
-		return err
-	}
-
+	_, _ = io.Copy(io.Discard, resp.Body)
 	return nil
 }
 
-func isDuplicateError(err *api.HTTPError) bool {
-	return err.StatusCode == 422 && len(err.Errors) == 1 &&
-		err.Errors[0].Field == "key" && err.Errors[0].Message == "key is already in use"
+func isGpgKeyArmored(keyBytes []byte) bool {
+	return bytes.Contains(keyBytes, []byte("-----BEGIN "))
 }