diff --git a/cli.c b/cli.c
index bc264cd..b44a482 100644
--- a/cli.c
+++ b/cli.c
@@ -44,7 +44,7 @@ main(int argc, char *argv[])
 
 	counter = 0;
 	do_hotp = 0;
-	while ((ch = getopt(argc, argv, "H:")) != -1) {
+	while ((ch = getopt(argc, argv, "H:T:")) != -1) {
 		switch (ch) {
 		case 'H':
 			counter = mystrtonum(optarg, 0, LLONG_MAX, &errstr);
@@ -52,6 +52,12 @@ main(int argc, char *argv[])
 				errx(1, "counter is %s: %s", errstr, optarg);
 			do_hotp = 1;
 			break;
+		case 'T':
+			counter = mystrtonum(optarg, 0, LLONG_MAX, &errstr);
+			if (errstr != NULL)
+				errx(1, "counter is %s: %s", errstr, optarg);
+			do_hotp = 0;
+			break;
 		default:
 			usage();
 		}
@@ -67,8 +73,13 @@ main(int argc, char *argv[])
 		if (r == -1)
 			errx(1, "couldn't calculate HOTP");
 		printf("%" PRId32 "\n", r);
-	} else
-		errx(1, "TOTP unimplemented");
+	} else {
+		r = totp(OTP_HMAC_SHA1, argv[0], strlen(argv[0]), counter,
+		    30, 8);
+		if (r == -1)
+			errx(1, "couldn't calculate TOTP");
+		printf("%" PRId32 "\n", r);
+	}
 
 	return 0;
 }
diff --git a/otp.c b/otp.c
index 472cb0a..aa7f1ff 100644
--- a/otp.c
+++ b/otp.c
@@ -78,5 +78,5 @@ int32_t
 totp(enum otp_hmac hmac, const void *key, size_t key_len, uint64_t t,
     unsigned int step, unsigned int digits)
 {
-	return -1;
+	return hotp(hmac, key, key_len, t / step, digits);
 }
diff --git a/run-tests.sh b/run-tests.sh
index 81561e7..d6515da 100644
--- a/run-tests.sh
+++ b/run-tests.sh
@@ -44,6 +44,25 @@ case_eq 162583 ./otpcli -H 7 "$HOTP_SECRET"
 case_eq 399871 ./otpcli -H 8 "$HOTP_SECRET"
 case_eq 520489 ./otpcli -H 9 "$HOTP_SECRET"
 
+case_eq 94287082 ./otpcli -T 59 "$HOTP_SECRET"
+#case_eq 46119246 ./otpcli -h sha256 -T 59 "$HOTP_SECRET"
+#case_eq 90693936 ./otpcli -h sha512 -T 59 "$HOTP_SECRET"
+case_eq 07081804 ./otpcli -T 1111111109 "$HOTP_SECRET"
+#case_eq 68084774 ./otpcli -h sha256 -T 1111111109 "$HOTP_SECRET"
+#case_eq 25091201 ./otpcli -h sha512 -T 1111111109 "$HOTP_SECRET"
+case_eq 14050471 ./otpcli -T 1111111111 "$HOTP_SECRET"
+#case_eq 67062674 ./otpcli -h sha256 -T 1111111111 "$HOTP_SECRET"
+#case_eq 99943326 ./otpcli -h sha512 -T 1111111111 "$HOTP_SECRET"
+case_eq 89005924 ./otpcli -T 1234567890 "$HOTP_SECRET"
+#case_eq 91819424 ./otpcli -h sha256 -T 1234567890 "$HOTP_SECRET"
+#case_eq 93441116 ./otpcli -h sha512 -T 1234567890 "$HOTP_SECRET"
+case_eq 69279037 ./otpcli -T 2000000000 "$HOTP_SECRET"
+#case_eq 90698825 ./otpcli -h sha256 -T 2000000000 "$HOTP_SECRET"
+#case_eq 38618901 ./otpcli -h sha512 -T 2000000000 "$HOTP_SECRET"
+case_eq 65353130 ./otpcli -T 20000000000 "$HOTP_SECRET"
+#case_eq 77737706 ./otpcli -h sha256 -T 20000000000 "$HOTP_SECRET"
+#case_eq 47863826 ./otpcli -h sha512 -T 20000000000 "$HOTP_SECRET"
+
 if [ $_test_rc -eq 0 ]; then
 	printf "All %u tests completed successfully!\n" "$_test_nr" >&2
 else