diff --git a/src/cmd/compile/internal/abt/avlint32.go b/src/cmd/compile/internal/abt/avlint32.go
index eed5fa5d38..e0998f5bac 100644
--- a/src/cmd/compile/internal/abt/avlint32.go
+++ b/src/cmd/compile/internal/abt/avlint32.go
@@ -339,7 +339,7 @@ func (t *T) String() string {
 		}
 		b.WriteString(strconv.FormatInt(int64(k), 10))
 		b.WriteString(":")
-		b.WriteString(fmt.Sprint(v))
+		fmt.Fprint(&b, v)
 	}
 	return b.String()
 }
diff --git a/src/cmd/compile/internal/ssagen/ssa.go b/src/cmd/compile/internal/ssagen/ssa.go
index 21b8fbc8ec..88d43b9915 100644
--- a/src/cmd/compile/internal/ssagen/ssa.go
+++ b/src/cmd/compile/internal/ssagen/ssa.go
@@ -7271,7 +7271,7 @@ func genssa(f *ssa.Func, pp *objw.Progs) {
 			}
 			buf.WriteString("</dt>")
 			buf.WriteString("<dd class=\"ssa-prog\">")
-			buf.WriteString(fmt.Sprintf("%.5d <span class=\"l%v line-number\">(%s)</span> %s", p.Pc, p.InnermostLineNumber(), p.InnermostLineNumberHTML(), html.EscapeString(p.InstructionString())))
+			fmt.Fprintf(&buf, "%.5d <span class=\"l%v line-number\">(%s)</span> %s", p.Pc, p.InnermostLineNumber(), p.InnermostLineNumberHTML(), html.EscapeString(p.InstructionString()))
 			buf.WriteString("</dd>")
 		}
 		buf.WriteString("</dl>")
diff --git a/src/cmd/compile/internal/syntax/scanner_test.go b/src/cmd/compile/internal/syntax/scanner_test.go
index 2deb3bbf84..450ec1ff8a 100644
--- a/src/cmd/compile/internal/syntax/scanner_test.go
+++ b/src/cmd/compile/internal/syntax/scanner_test.go
@@ -88,10 +88,10 @@ func TestEmbeddedTokens(t *testing.T) {
 	// make source
 	var buf bytes.Buffer
 	for i, s := range sampleTokens {
-		buf.WriteString("\t\t\t\t"[:i&3])                            // leading indentation
-		buf.WriteString(s.src)                                       // token
-		buf.WriteString("        "[:i&7])                            // trailing spaces
-		buf.WriteString(fmt.Sprintf("/*line foo:%d */ // bar\n", i)) // comments + newline (don't crash w/o directive handler)
+		buf.WriteString("\t\t\t\t"[:i&3])                 // leading indentation
+		buf.WriteString(s.src)                            // token
+		buf.WriteString("        "[:i&7])                 // trailing spaces
+		fmt.Fprintf(&buf, "/*line foo:%d */ // bar\n", i) // comments + newline (don't crash w/o directive handler)
 	}
 
 	// scan source
diff --git a/src/cmd/compile/internal/types/fmt.go b/src/cmd/compile/internal/types/fmt.go
index c6e99d26c2..990f2e5f52 100644
--- a/src/cmd/compile/internal/types/fmt.go
+++ b/src/cmd/compile/internal/types/fmt.go
@@ -577,7 +577,7 @@ func tconv2(b *bytes.Buffer, t *Type, verb rune, mode fmtMode, visited map[*Type
 		} else {
 			b.WriteString("tp")
 			// Print out the pointer value for now to disambiguate type params
-			b.WriteString(fmt.Sprintf("%p", t))
+			fmt.Fprintf(b, "%p", t)
 		}
 
 	case TUNION:
diff --git a/src/go/types/exprstring.go b/src/go/types/exprstring.go
index e19d79d9c8..3cdf30fba1 100644
--- a/src/go/types/exprstring.go
+++ b/src/go/types/exprstring.go
@@ -33,7 +33,7 @@ func WriteExpr(buf *bytes.Buffer, x ast.Expr) {
 
 	switch x := x.(type) {
 	default:
-		buf.WriteString(fmt.Sprintf("(ast: %T)", x)) // nil, ast.BadExpr, ast.KeyValueExpr
+		fmt.Fprintf(buf, "(ast: %T)", x) // nil, ast.BadExpr, ast.KeyValueExpr
 
 	case *ast.Ident:
 		buf.WriteString(x.Name)
diff --git a/src/internal/fmtsort/sort_test.go b/src/internal/fmtsort/sort_test.go
index 11befca6f1..cddcf70159 100644
--- a/src/internal/fmtsort/sort_test.go
+++ b/src/internal/fmtsort/sort_test.go
@@ -147,7 +147,7 @@ func sprint(data any) string {
 		}
 		b.WriteString(sprintKey(key))
 		b.WriteRune(':')
-		b.WriteString(fmt.Sprint(om.Value[i]))
+		fmt.Fprint(b, om.Value[i])
 	}
 	return b.String()
 }
diff --git a/src/runtime/trace/annotation_test.go b/src/runtime/trace/annotation_test.go
index 31fccef206..69ea8f2d3b 100644
--- a/src/runtime/trace/annotation_test.go
+++ b/src/runtime/trace/annotation_test.go
@@ -147,7 +147,7 @@ func TestUserTaskRegion(t *testing.T) {
 		pretty := func(data []testData) string {
 			var s strings.Builder
 			for _, d := range data {
-				s.WriteString(fmt.Sprintf("\t%+v\n", d))
+				fmt.Fprintf(&s, "\t%+v\n", d)
 			}
 			return s.String()
 		}
diff --git a/src/runtime/wincallback.go b/src/runtime/wincallback.go
index 442a984708..9ec2027f97 100644
--- a/src/runtime/wincallback.go
+++ b/src/runtime/wincallback.go
@@ -62,7 +62,7 @@ func genasmArm() {
 TEXT runtime·callbackasm(SB),NOSPLIT|NOFRAME,$0
 `)
 	for i := 0; i < maxCallback; i++ {
-		buf.WriteString(fmt.Sprintf("\tMOVW\t$%d, R12\n", i))
+		fmt.Fprintf(&buf, "\tMOVW\t$%d, R12\n", i)
 		buf.WriteString("\tB\truntime·callbackasm1(SB)\n")
 	}
 
@@ -90,7 +90,7 @@ func genasmArm64() {
 TEXT runtime·callbackasm(SB),NOSPLIT|NOFRAME,$0
 `)
 	for i := 0; i < maxCallback; i++ {
-		buf.WriteString(fmt.Sprintf("\tMOVD\t$%d, R12\n", i))
+		fmt.Fprintf(&buf, "\tMOVD\t$%d, R12\n", i)
 		buf.WriteString("\tB\truntime·callbackasm1(SB)\n")
 	}
 
@@ -104,12 +104,12 @@ TEXT runtime·callbackasm(SB),NOSPLIT|NOFRAME,$0
 func gengo() {
 	var buf bytes.Buffer
 
-	buf.WriteString(fmt.Sprintf(`// Code generated by wincallback.go using 'go generate'. DO NOT EDIT.
+	fmt.Fprintf(&buf, `// Code generated by wincallback.go using 'go generate'. DO NOT EDIT.
 
 package runtime
 
 const cb_max = %d // maximum number of windows callbacks allowed
-`, maxCallback))
+`, maxCallback)
 	err := os.WriteFile("zcallback_windows.go", buf.Bytes(), 0666)
 	if err != nil {
 		fmt.Fprintf(os.Stderr, "wincallback: %s\n", err)