diff --git a/PR.md b/PR.md
new file mode 100644
index 0000000..4c26d1c
--- /dev/null
+++ b/PR.md
@@ -0,0 +1,74 @@
+# fix(strutil): BaseConv family returns "0" for zero instead of empty string
+
+## Problem
+
+Converting the value zero through the base-conversion helpers returns an empty
+string instead of `"0"`:
+
+```go
+strutil.BaseConv("0", 10, 16)   // "" , want "0"
+strutil.BaseConv("0", 16, 10)   // "" , want "0"
+strutil.Base10Conv("0", 62)     // "" , want "0"
+strutil.BaseConvInt(0, 64)      // "" , want "0"
+```
+
+This is also internally inconsistent: `BaseConvInt` returns the correct `"0"`
+for small bases because it delegates to `strconv.FormatUint`/`big.Int.Text`,
+but returns `""` for bases in `(62, 64]`, which go through the template path:
+
+```go
+strutil.BaseConvInt(0, 16)      // "0"  (strconv path)
+strutil.BaseConvInt(0, 64)      // ""   (template path)
+```
+
+## Root cause
+
+`strutil/convbase.go`, `BaseConvIntByTpl`:
+
+```go
+func BaseConvIntByTpl(dec uint64, toBase string) string {
+	var res string
+	toLen := uint64(len(toBase))
+	for dec > 0 {                 // never runs when dec == 0
+		res = string(toBase[dec%toLen]) + res
+		dec /= toLen
+	}
+	return res                    // returns "" for dec == 0
+}
+```
+
+The loop condition `dec > 0` is never entered when `dec == 0`, so the function
+returns the zero-value empty string. Every public entry point that reaches the
+template path (`BaseConvIntByTpl`, `BaseConvByTpl`, `BaseConv`, `Base10Conv`,
+`BaseConvInt` for base > 62) inherits the defect.
+
+## Fix
+
+Handle the zero case explicitly by emitting the zero digit of the target base
+(the first character of the template), and guard against an empty template to
+avoid an out-of-range index:
+
+```go
+if toLen == 0 {
+	return res
+}
+if dec == 0 {
+	return string(toBase[0])
+}
+```
+
+## Test
+
+Added `TestBaseConv_zero` in `strutil/convbase_test.go` covering `BaseConv`,
+`Base10Conv`, `BaseConvInt` (small and large bases) and `BaseConvIntByTpl`.
+
+- Gate: `go test ./strutil/ -run 'TestBaseConv|TestBase10Conv'` -> ok (PASS)
+- `go vet ./strutil/` -> exit 0
+- `go build ./...` -> exit 0
+
+Counterfactual: reverting the change in `BaseConvIntByTpl` makes the new test
+fail with `actual: string("")` vs `expect: string("0")`.
+
+Note: `TestDateSNv3/dateLen4_base62` in `strutil/gensn_test.go` is flaky and
+already fails on the unmodified base commit (it asserts uniqueness of randomly
+generated serial numbers over 60 iterations); it is unrelated to this change.
diff --git a/strutil/convbase.go b/strutil/convbase.go
index d15fc53..6ae7ac4 100644
--- a/strutil/convbase.go
+++ b/strutil/convbase.go
@@ -100,6 +100,16 @@ func BaseConvIntByTpl(dec uint64, toBase string) string {
 	// convert to new base
 	var res string
 	toLen := uint64(len(toBase))
+	if toLen == 0 {
+		return res
+	}
+
+	// zero maps to the zero digit of the target base, otherwise the loop below
+	// would produce an empty string for a valid input.
+	if dec == 0 {
+		return string(toBase[0])
+	}
+
 	for dec > 0 {
 		res = string(toBase[dec%toLen]) + res
 		dec /= toLen
diff --git a/strutil/convbase_test.go b/strutil/convbase_test.go
index 86d9052..a03555f 100644
--- a/strutil/convbase_test.go
+++ b/strutil/convbase_test.go
@@ -7,6 +7,21 @@ import (
 	"github.com/gookit/goutil/x/assert"
 )
 
+func TestBaseConv_zero(t *testing.T) {
+	// Zero must convert to the zero digit of the target base, not an empty
+	// string. This also keeps BaseConvInt consistent across all bases: the
+	// strconv-backed path already returns "0" for small bases.
+	assert.Eq(t, "0", strutil.BaseConv("0", 10, 16))
+	assert.Eq(t, "0", strutil.BaseConv("0", 16, 10))
+	assert.Eq(t, "0", strutil.Base10Conv("0", 62))
+
+	assert.Eq(t, "0", strutil.BaseConvInt(0, 16))
+	assert.Eq(t, "0", strutil.BaseConvInt(0, 62))
+	assert.Eq(t, "0", strutil.BaseConvInt(0, 64))
+
+	assert.Eq(t, "0", strutil.BaseConvIntByTpl(0, strutil.Base64Chars))
+}
+
 func TestBaseConv(t *testing.T) {
 	tests := []struct {
 		give string