diff --git a/src/humanize/number.py b/src/humanize/number.py
index f060b794..0b5b99b7 100644
--- a/src/humanize/number.py
+++ b/src/humanize/number.py
@@ -548,14 +548,14 @@ def metric(value: float, unit: str = "", precision: int = 3) -> str:
         return _format_not_finite(value)
     exponent = int(math.floor(math.log10(abs(value)))) if value != 0 else 0
 
-    if exponent >= 27 or exponent < -24:
+    if exponent >= 33 or exponent < -30:
         return scientific(value, precision - 1) + unit
 
     value /= 10 ** (exponent // 3 * 3)
     if exponent >= 3:
-        ordinal_ = "kMGTPEZY"[exponent // 3 - 1]
+        ordinal_ = "kMGTPEZYRQ"[exponent // 3 - 1]
     elif exponent < 0:
-        ordinal_ = "mμnpfazy"[(-exponent - 1) // 3]
+        ordinal_ = "mμnpfazyrq"[(-exponent - 1) // 3]
     else:
         ordinal_ = ""
     value_ = format(value, ".%if" % (precision - (exponent % 3) - 1))
diff --git a/tests/test_number.py b/tests/test_number.py
index 9f57c64c..e66beed0 100644
--- a/tests/test_number.py
+++ b/tests/test_number.py
@@ -245,8 +245,14 @@ def test_clamp(test_args: list[typing.Any], expected: str) -> None:
         ([200_000], "200 k"),
         ([1e25, "m"], "10.0 Ym"),
         ([1e26, "m"], "100 Ym"),
-        ([1e27, "A"], "1.00 x 10²⁷A"),
-        ([1.234e28, "A"], "1.23 x 10²⁸A"),
+        ([1e27, "A"], "1.00 RA"),
+        ([1.234e28, "A"], "12.3 RA"),
+        ([1.234e-28, "A"], "123 qA"),
+        ([1.235e29, "A"], "124 RA"),
+        ([2.56e-30, "V"], "2.56 qV"),
+        ([2.596e32, "F"], "260 QF"),
+        ([1e50], "1.00 x 10⁵⁰"),
+        ([1e-50], "1.00 x 10⁻⁵⁰"),
         ([-1500, "V"], "-1.50 kV"),
         ([0.12], "120 m"),
         ([0.012], "12.0 m"),
@@ -254,8 +260,8 @@ def test_clamp(test_args: list[typing.Any], expected: str) -> None:
         ([0.00012], "120 μ"),
         ([1e-23], "10.0 y"),
         ([1e-24], "1.00 y"),
-        ([1e-25], "1.00 x 10⁻²⁵"),
-        ([1e-26], "1.00 x 10⁻²⁶"),
+        ([1e-25], "100 r"),
+        ([1e-26], "10.0 r"),
         ([1, "°"], "1.00°"),
         ([0.1, "°"], "100m°"),
         ([100], "100"),