diff --git a/changelog/12229.txt b/changelog/12229.txt
new file mode 100644
index 0000000000000..6503ba5e97c9f
--- /dev/null
+++ b/changelog/12229.txt
@@ -0,0 +1,3 @@
+```release-note:bug
+core: fix byte printing for diagnose disk checks
+```
diff --git a/go.mod b/go.mod
index 0ab34636831ad..aedb0745b29ef 100644
--- a/go.mod
+++ b/go.mod
@@ -41,6 +41,7 @@ require (
 	github.com/docker/go-connections v0.4.0
 	github.com/dsnet/compress v0.0.1 // indirect
 	github.com/duosecurity/duo_api_golang v0.0.0-20190308151101-6c680f768e74
+	github.com/dustin/go-humanize v1.0.0
 	github.com/elazarl/go-bindata-assetfs v1.0.1-0.20200509193318-234c15e7648f
 	github.com/fatih/color v1.11.0
 	github.com/fatih/structs v1.1.0
diff --git a/vault/diagnose/os_common.go b/vault/diagnose/os_common.go
index 6d4658c006629..937c4c99813dd 100644
--- a/vault/diagnose/os_common.go
+++ b/vault/diagnose/os_common.go
@@ -7,6 +7,7 @@ import (
 	"fmt"
 	"strings"
 
+	"github.com/dustin/go-humanize"
 	"github.com/shirou/gopsutil/disk"
 )
 
@@ -31,10 +32,10 @@ partLoop:
 			Warn(ctx, fmt.Sprintf("Could not obtain partition usage for %s: %v.", partition.Mountpoint, err))
 		} else {
 			if usage.UsedPercent > 95 {
-				SpotWarn(ctx, testName, fmt.Sprintf(partition.Mountpoint+" is %d percent full.", usage.UsedPercent),
+				SpotWarn(ctx, testName, fmt.Sprintf(partition.Mountpoint+" is %.2f percent full.", usage.UsedPercent),
 					Advice("It is recommended to have more than five percent of the partition free."))
-			} else if usage.Free < 2<<30 {
-				SpotWarn(ctx, testName, partition.Mountpoint+" has %d bytes full.",
+			} else if usage.Free < 1<<30 {
+				SpotWarn(ctx, testName, fmt.Sprintf(partition.Mountpoint+" has %s free.", humanize.Bytes(usage.Free)),
 					Advice("It is recommended to have at least 1 GB of space free per partition."))
 			} else {
 				SpotOk(ctx, testName, partition.Mountpoint+" usage ok.")