diff --git a/buildtools.json b/buildtools.json
index 6b3e85e..433b176 100644
--- a/buildtools.json
+++ b/buildtools.json
@@ -77,4 +77,4 @@
       "checksum": "6317c36bec63158038381e8878601151ae996310fef58306f70cb03f1b46ef7f"
     }
   ]
-}
+}
\ No newline at end of file
diff --git a/cmd/bindownloader/config.go b/cmd/bindownloader/config.go
index 2bd9572..e3af7cd 100644
--- a/cmd/bindownloader/config.go
+++ b/cmd/bindownloader/config.go
@@ -2,19 +2,23 @@ package main
 
 import (
 	"encoding/json"
+	"fmt"
 	"io/ioutil"
+	"path"
 
 	"github.com/alecthomas/kong"
 	"github.com/willabides/bindownloader"
 )
 
 var configKongVars = kong.Vars{
-	"config_format_help":    `formats the config file`,
-	"config_checksums_help": `update checksums in the config file`,
+	"config_format_help":        `formats the config file`,
+	"config_checksums_help":     `update checksums in the config file`,
+	"config_checksums_bin_help": `name of the binary to update`,
 }
 
 type configCmd struct {
-	Format configFmtCmd `kong:"cmd,help=${config_format_help}"`
+	Format          configFmtCmd             `kong:"cmd,help=${config_format_help}"`
+	UpdateChecksums configUpdateChecksumsCmd `kong:"cmd,help=${config_checksums_bin_help}"`
 }
 
 type configFmtCmd struct{}
@@ -30,3 +34,39 @@ func (c configFmtCmd) Run() error {
 	}
 	return ioutil.WriteFile(cli.Configfile, b, 0600)
 }
+
+type configUpdateChecksumsCmd struct {
+	TargetFile string `kong:"required=true,arg,help=${config_checksums_bin_help}"`
+}
+
+func (d *configUpdateChecksumsCmd) Run(*kong.Context) error {
+	config, err := bindownloader.LoadConfigFile(cli.Configfile)
+	if err != nil {
+		return fmt.Errorf("error loading config from %q", cli.Configfile)
+	}
+	binary := path.Base(d.TargetFile)
+	binDir := path.Dir(d.TargetFile)
+
+	downloaders, ok := config[binary]
+	if !ok {
+		return fmt.Errorf("nothing configured for %q", binary)
+	}
+
+	for _, downloader := range downloaders {
+		err = downloader.UpdateChecksum(bindownloader.UpdateChecksumOpts{
+			DownloaderName: binary,
+			CellarDir:      cli.CellarDir,
+			TargetDir:      binDir,
+		})
+		if err != nil {
+			return err
+		}
+	}
+
+	b, err := json.MarshalIndent(&config, "", "  ")
+	if err != nil {
+		return err
+	}
+
+	return ioutil.WriteFile(cli.Configfile, b, 0600)
+}
diff --git a/downloader.go b/downloader.go
index 1189fa2..66ac393 100644
--- a/downloader.go
+++ b/downloader.go
@@ -139,6 +139,12 @@ func (d *Downloader) download(downloadDir string) error {
 	return downloadFile(dlPath, d.URL)
 }
 
+func (d *Downloader) setDefaultBinName(defaultName string) {
+	if d.BinName == "" {
+		d.BinName = defaultName
+	}
+}
+
 func (d *Downloader) validateChecksum(targetDir string) error {
 	targetFile, err := d.downloadablePath(targetDir)
 	if err != nil {
@@ -162,6 +168,45 @@ got: %s`, targetFile, d.Checksum, result)
 	return nil
 }
 
+//UpdateChecksumOpts options for UpdateChecksum
+type UpdateChecksumOpts struct {
+	// DownloaderName is the downloader's key from the config file
+	DownloaderName string
+	// CellarDir is the directory where downloads and extractions will be placed.  Default is a <TargetDir>/.bindownloader
+	CellarDir string
+	// TargetDir is the directory where the executable should end up
+	TargetDir string
+}
+
+//UpdateChecksum updates the checksum based on a fresh download
+func (d *Downloader) UpdateChecksum(opts UpdateChecksumOpts) error {
+	cellarDir := opts.CellarDir
+	if cellarDir == "" {
+		cellarDir = filepath.Join(opts.TargetDir, ".bindownloader")
+	}
+
+	downloadDir := filepath.Join(cellarDir, "downloads", d.downloadsSubName())
+
+	err := d.download(downloadDir)
+	if err != nil {
+		log.Printf("error downloading: %v", err)
+		return err
+	}
+
+	dlPath, err := d.downloadablePath(downloadDir)
+	if err != nil {
+		return err
+	}
+
+	checkSum, err := fileChecksum(dlPath)
+	if err != nil {
+		return err
+	}
+
+	d.Checksum = checkSum
+	return nil
+}
+
 //InstallOpts options for Install
 type InstallOpts struct {
 	// DownloaderName is the downloader's key from the config file
@@ -184,9 +229,7 @@ func (d *Downloader) extractsSubName() string {
 
 //Install downloads and installs a bin
 func (d *Downloader) Install(opts InstallOpts) error {
-	if d.BinName == "" {
-		d.BinName = opts.DownloaderName
-	}
+	d.setDefaultBinName(opts.DownloaderName)
 	cellarDir := opts.CellarDir
 	if cellarDir == "" {
 		cellarDir = filepath.Join(opts.TargetDir, ".bindownloader")