diff --git a/api/handler/put.go b/api/handler/put.go
index 3e5e287f..ee8764ef 100644
--- a/api/handler/put.go
+++ b/api/handler/put.go
@@ -54,17 +54,29 @@ func (p *postPolicy) condition(key string) *policyCondition {
 	return nil
 }
 
-func (p *postPolicy) CheckContentLength(size uint64) bool {
+func (p *postPolicy) CheckContentLength(size uint64) error {
 	if p.empty {
-		return true
+		return nil
 	}
 	for _, condition := range p.Conditions {
 		if condition.Matching == "content-length-range" {
-			length := strconv.FormatUint(size, 10)
-			return condition.Key <= length && length <= condition.Value
+			start, err := strconv.ParseUint(condition.Key, 10, 64)
+			if err != nil {
+				return errInvalidCondition
+			}
+
+			end, err := strconv.ParseUint(condition.Value, 10, 64)
+			if err != nil {
+				return errInvalidCondition
+			}
+
+			if start <= size && size <= end {
+				return nil
+			}
+			return fmt.Errorf("length of the content did not fall within the range specified in the condition")
 		}
 	}
-	return true
+	return nil
 }
 
 func (p *policyCondition) match(value string) bool {
@@ -560,8 +572,8 @@ func (h *handler) PostObject(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	if !policy.CheckContentLength(size) {
-		h.logAndSendError(ctx, w, "invalid content-length", reqInfo, apierr.GetAPIError(apierr.ErrInvalidArgument))
+	if err := policy.CheckContentLength(size); err != nil {
+		h.logAndSendError(ctx, w, err.Error(), reqInfo, apierr.GetAPIError(apierr.ErrPostPolicyConditionInvalidFormat))
 		return
 	}
 
diff --git a/api/handler/put_test.go b/api/handler/put_test.go
index 5178efce..bc4a063f 100644
--- a/api/handler/put_test.go
+++ b/api/handler/put_test.go
@@ -1206,6 +1206,104 @@ func TestFormEncryptionParamsBase(t *testing.T) {
 	}
 }
 
+func TestCheckContentLength(t *testing.T) {
+	contentLength := "content-length-range"
+	notFallError := "length of the content did not fall within the range specified in the condition"
+	parseError := "invalid condition"
+	for _, tc := range []struct {
+		name        string
+		matching    string
+		key         string
+		value       string
+		size        uint64
+		errMsg      string
+		emptyPolicy bool
+	}{
+		{
+			name:     "valid",
+			matching: contentLength,
+			key:      "0",
+			value:    "1000",
+			size:     50,
+		},
+		{
+			name:     "valid lower limit",
+			matching: contentLength,
+			key:      "5",
+			value:    "100",
+			size:     5,
+		},
+		{
+			name:     "valid upper limit",
+			matching: contentLength,
+			key:      "5",
+			value:    "100",
+			size:     100,
+		},
+		{
+			name:     "invalid size value (too small)",
+			matching: contentLength,
+			key:      "5",
+			value:    "100",
+			size:     2,
+			errMsg:   notFallError,
+		},
+		{
+			name:     "invalid size value (to high)",
+			matching: contentLength,
+			key:      "5",
+			value:    "100",
+			size:     200,
+			errMsg:   notFallError,
+		},
+		{
+			name: "no matching",
+		},
+		{
+			name:     "invalid key type",
+			matching: contentLength,
+			key:      "invalid",
+			value:    "100",
+			size:     10,
+			errMsg:   parseError,
+		},
+		{
+			name:     "invalid value type",
+			matching: contentLength,
+			key:      "5",
+			value:    "invalid",
+			size:     10,
+			errMsg:   parseError,
+		},
+		{
+			name:        "empty policy",
+			emptyPolicy: true,
+		},
+	} {
+		t.Run(tc.name, func(t *testing.T) {
+			policy := &postPolicy{
+				Conditions: []*policyCondition{
+					{
+						Matching: tc.matching,
+						Key:      tc.key,
+						Value:    tc.value,
+					},
+				},
+				empty: tc.emptyPolicy,
+			}
+
+			err := policy.CheckContentLength(tc.size)
+			if tc.errMsg != "" {
+				require.Error(t, err)
+				require.Contains(t, err.Error(), tc.errMsg)
+				return
+			}
+
+			require.NoError(t, err)
+		})
+	}
+}
+
 func prepareRequestForEncryption(hc *handlerContext, algo, key, md5, tlsTermination string, reqWithoutTLS, reqWithoutSSE, isCopySource bool) *http.Request {
 	r := httptest.NewRequest(http.MethodPost, "/", nil)