diff --git a/copyparty/httpcli.py b/copyparty/httpcli.py
index 26160133d..f2f3e4a1e 100644
--- a/copyparty/httpcli.py
+++ b/copyparty/httpcli.py
@@ -4974,14 +4974,15 @@ class HttpCli(object):
 
                 a, b = hrange.split("=", 1)[1].split("-")
 
+                if b.strip():
+                    upper = 1 + int(b.strip())
+                else:
+                    upper = file_sz
+
                 if a.strip():
                     lower = int(a.strip())
                 else:
-                    lower = 0
-
-                if b.strip():
-                    upper = int(b.strip()) + 1
-                else:
+                    lower = 1 + file_sz - upper
                     upper = file_sz
 
                 if upper > file_sz:
diff --git a/tests/test_httpcli.py b/tests/test_httpcli.py
index fac0cf2fb..fba9f4b84 100644
--- a/tests/test_httpcli.py
+++ b/tests/test_httpcli.py
@@ -104,6 +104,22 @@ class TestHttpCli(unittest.TestCase):
                     eprint("\033[33m{}\n# {}\033[0m".format(ret, furl))
                     self.fail()
 
+                if tctr == 1:
+                    # http206
+                    full = ret
+                    self.hcurl(furl, "Range: bytes=0-0", full[:1])
+                    self.hcurl(furl, "Range: bytes=0-4", full[0:5])
+                    self.hcurl(furl, "Range: bytes=1-4", full[1:5])
+                    self.hcurl(furl, "Range: bytes=-1", full[-1:])
+                    self.hcurl(furl, "Range: bytes=-7", full[-7:])
+                    self.hcurl(furl, "Range: bytes=0-", full)
+                    self.hcurl(furl, "Range: bytes=1-", full[1:])
+                    self.hcurl(furl, "Range: bytes=2-", full[2:])
+                    for zs in ("0--1", "--1", "-0", ""):
+                        h, _ = self.hcurl(furl, "Range: bytes=" + zs, None)
+                        self.assertEqual(h.split(" ")[1], "416")
+                    return
+
                 # file browser: html
                 h, ret = self.curl(durl)
                 res = "'{}'".format(self.fn) in ret
@@ -243,6 +259,15 @@ class TestHttpCli(unittest.TestCase):
 
         return conn.s._reply.decode("utf-8").split("\r\n\r\n", 1)
 
+    def hcurl(self, url, hdr, expected):
+        zs = "GET /%s HTTP/1.1\r\n%s\r\nCookie: cppwd=o\r\nConnection: close\r\n\r\n"
+        conn = self.conn.setbuf((zs % (url, hdr)).encode("utf-8"))
+        HttpCli(conn).run()
+        h, rsp = conn.s._reply.decode("utf-8").split("\r\n\r\n", 1)
+        if expected is not None:
+            self.assertEqual(rsp, expected)
+        return h, rsp
+
     def propfind(self, url, depth=1):
         zs = "PROPFIND /%s HTTP/1.1\r\nDepth: %d\r\nPW: o\r\nConnection: close\r\n\r\n"
         buf = zs % (url, depth)