diff --git a/vm/src/cformat.rs b/vm/src/cformat.rs
index 0d86609bf..e372384a8 100644
--- a/vm/src/cformat.rs
+++ b/vm/src/cformat.rs
@@ -831,6 +831,20 @@ mod tests {
                 .format_float(f64::from(1.2345678901)),
             "1.234568".to_string()
         );
+        assert_eq!(
+            "%f"
+                .parse::<CFormatSpec>()
+                .unwrap()
+                .format_number(&BigInt::from(123)),
+            "123.000000".to_string()
+        );
+        assert_eq!(
+            "%f"
+                .parse::<CFormatSpec>()
+                .unwrap()
+                .format_number(&BigInt::from(-123)),
+            "-123.000000".to_string()
+        )
     }
 
     #[test]
diff --git a/vm/src/obj/objstr.rs b/vm/src/obj/objstr.rs
index 95b4d0f05..1e05fb862 100644
--- a/vm/src/obj/objstr.rs
+++ b/vm/src/obj/objstr.rs
@@ -1222,16 +1222,19 @@ fn do_cformat_specifier(
             Ok(format_spec.format_number(objint::get_value(&obj)))
         }
         CFormatType::Float(_) => {
-            if !objtype::isinstance(&obj, &vm.ctx.float_type()) {
-                let required_type_string = "an floating point";
-                return Err(vm.new_type_error(format!(
+            if objtype::isinstance(&obj, &vm.ctx.float_type()) {
+                Ok(format_spec.format_float(objfloat::get_value(&obj)))
+            } else if objtype::isinstance(&obj, &vm.ctx.int_type()){
+                Ok(format_spec.format_float(objint::get_value(&obj).to_f64().unwrap()))
+            } else {
+                let required_type_string = "an floating point or integer";
+                Err(vm.new_type_error(format!(
                     "%{} format: {} is required, not {}",
                     format_spec.format_char,
                     required_type_string,
                     obj.class()
-                )));
+                )))
             }
-            Ok(format_spec.format_float(objfloat::get_value(&obj)))
         }
         CFormatType::Character => {
             let char_string = {