diff --git a/chain/types/bigint_test.go b/chain/types/bigint_test.go
index 43e5633b2..60130277e 100644
--- a/chain/types/bigint_test.go
+++ b/chain/types/bigint_test.go
@@ -43,7 +43,7 @@ func TestBigIntSerializationRoundTrip(t *testing.T) {
 
 func TestFilRoundTrip(t *testing.T) {
 	testValues := []string{
-		"0", "1", "1.001", "100.10001", "101100", "5000.01", "5000",
+		"0 FIL", "1 FIL", "1.001 FIL", "100.10001 FIL", "101100 FIL", "5000.01 FIL", "5000 FIL",
 	}
 
 	for _, v := range testValues {
diff --git a/chain/types/fil.go b/chain/types/fil.go
index 527078e0f..1d912d9c0 100644
--- a/chain/types/fil.go
+++ b/chain/types/fil.go
@@ -13,9 +13,9 @@ type FIL BigInt
 func (f FIL) String() string {
 	r := new(big.Rat).SetFrac(f.Int, big.NewInt(int64(build.FilecoinPrecision)))
 	if r.Sign() == 0 {
-		return "0"
+		return "0 FIL"
 	}
-	return strings.TrimRight(strings.TrimRight(r.FloatString(18), "0"), ".")
+	return strings.TrimRight(strings.TrimRight(r.FloatString(18), "0"), ".") + " FIL"
 }
 
 func (f FIL) Format(s fmt.State, ch rune) {
@@ -28,14 +28,35 @@ func (f FIL) Format(s fmt.State, ch rune) {
 }
 
 func ParseFIL(s string) (FIL, error) {
+	suffix := strings.TrimLeft(s, ".1234567890")
+	s = s[:len(s)-len(suffix)]
+	var attofil bool
+	if suffix != "" {
+		norm := strings.ToLower(strings.TrimSpace(suffix))
+		switch norm {
+		case "", "fil":
+		case "attofil", "afil":
+			attofil = true
+		default:
+			return FIL{}, fmt.Errorf("unrecognized suffix: %q", suffix)
+		}
+	}
+
 	r, ok := new(big.Rat).SetString(s)
 	if !ok {
 		return FIL{}, fmt.Errorf("failed to parse %q as a decimal number", s)
 	}
 
-	r = r.Mul(r, big.NewRat(int64(build.FilecoinPrecision), 1))
+	if !attofil {
+		r = r.Mul(r, big.NewRat(int64(build.FilecoinPrecision), 1))
+	}
+
 	if !r.IsInt() {
-		return FIL{}, fmt.Errorf("invalid FIL value: %q", s)
+		var pref string
+		if attofil {
+			pref = "atto"
+		}
+		return FIL{}, fmt.Errorf("invalid %sFIL value: %q", pref, s)
 	}
 
 	return FIL{r.Num()}, nil