diff --git a/README.md b/README.md
index a2e4b3a..ef61a23 100644
--- a/README.md
+++ b/README.md
@@ -51,6 +51,24 @@ Unit tests for an individual file can be built and run with `make fft_fr_test` f
 
 Thanks to [Acutest](https://github.com/mity/acutest) for the unit test harness, which is used here under the MIT licence.
 
+## Run benchmarks
+
+This will run all available benchmarks, for the default one second per test size:
+
+```
+cd src
+make bench
+```
+
+You can run individual benchmarks, and optionally specify how long to run each test size:
+
+```
+make fft_fr_bench
+./fft_fr_bench 5
+```
+
+Doing `make clean` should resolve any weird build issues.
+
 ## Prerequisites
 
  - Blst library (see above)
diff --git a/src/Makefile b/src/Makefile
index fa2de1a..b67685c 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -41,4 +41,5 @@ clean:
 	rm -f *.o
 	rm -f libckzg.a
 	rm -f $(TESTS)
+	rm -f $(BENCH)
 	rm -f a.out
diff --git a/src/bench_util.c b/src/bench_util.c
index cb03b5e..46a20dd 100644
--- a/src/bench_util.c
+++ b/src/bench_util.c
@@ -18,7 +18,7 @@
 #include "bench_util.h"
 #include "blst_util.h"
 
-unsigned long tdiff(timespec start, timespec end) {
+unsigned long tdiff(timespec_t start, timespec_t end) {
     return (end.tv_sec - start.tv_sec) * NANO + (end.tv_nsec - start.tv_nsec);
 }
 
diff --git a/src/bench_util.h b/src/bench_util.h
index 6c0e26e..797a2bb 100644
--- a/src/bench_util.h
+++ b/src/bench_util.h
@@ -17,11 +17,12 @@
 #include <time.h> // CLOCK_REALTIME, clock_gettime(), timespec
 #include "c_kzg.h"
 
-typedef struct timespec timespec;
+typedef struct timespec timespec_t;
 
 #define NANO 1000000000L
+#define NSEC 1
 
-unsigned long tdiff(timespec start, timespec end);
+unsigned long tdiff(timespec_t start, timespec_t end);
 uint64_t rand_uint64();
 blst_fr rand_fr();
 blst_p1 rand_g1();
diff --git a/src/fft_fr_bench.c b/src/fft_fr_bench.c
index 3677ad2..e28dfa1 100644
--- a/src/fft_fr_bench.c
+++ b/src/fft_fr_bench.c
@@ -14,19 +14,21 @@
  * limitations under the License.
  */
 
-#include <stdlib.h> // malloc(), free()
+#include <stdlib.h> // malloc(), free(), atoi()
 #include <stdio.h>  // printf()
 #include <assert.h> // assert()
+#include <unistd.h> // EXIT_SUCCESS/FAILURE
 #include "bench_util.h"
 #include "fft_fr.h"
 
 // Run the benchmark for `max_seconds` and return the time per iteration in nanoseconds.
 long run_bench(int scale, int max_seconds) {
-    timespec t0, t1;
+    timespec_t t0, t1;
     unsigned long total_time = 0, nits = 0;
     FFTSettings fs;
 
     assert(C_KZG_OK == new_fft_settings(&fs, scale));
+
     // Allocate on the heap to avoid stack overflow for large sizes
     blst_fr *data, *out;
     data = malloc(fs.max_width * sizeof(blst_fr));
@@ -51,11 +53,29 @@ long run_bench(int scale, int max_seconds) {
     return total_time / nits;
 }
 
-#define NSEC 1
+int main(int argc, char *argv[]) {
+    int nsec = 0;
 
-int main(void) {
-    printf("*** Benchmarking FFT_fr, %d second%s per test.\n", NSEC, NSEC == 1 ? "" : "s");
-    for (int scale = 4; scale < 16; scale++) {
-        printf("fft_fr/scale_%d %lu ns/op\n", scale, run_bench(scale, 1));
+    switch (argc) {
+    case 1:
+        nsec = NSEC;
+        break;
+    case 2:
+        nsec = atoi(argv[1]);
+        break;
+    default:
+        break;
+    };
+
+    if (nsec == 0) {
+        printf("Usage: %s [test time in seconds > 0]\n", argv[0]);
+        exit(EXIT_FAILURE);
     }
+
+    printf("*** Benchmarking FFT_fr, %d second%s per test.\n", nsec, nsec == 1 ? "" : "s");
+    for (int scale = 4; scale <= 15; scale++) {
+        printf("fft_fr/scale_%d %lu ns/op\n", scale, run_bench(scale, nsec));
+    }
+
+    return EXIT_SUCCESS;
 }
diff --git a/src/fft_g1_bench.c b/src/fft_g1_bench.c
index ef6e7b9..6be5fc5 100644
--- a/src/fft_g1_bench.c
+++ b/src/fft_g1_bench.c
@@ -14,19 +14,21 @@
  * limitations under the License.
  */
 
-#include <stdlib.h> // malloc(), free()
+#include <stdlib.h> // malloc(), free(), atoi()
 #include <stdio.h>  // printf()
 #include <assert.h> // assert()
+#include <unistd.h> // EXIT_SUCCESS/FAILURE
 #include "bench_util.h"
 #include "fft_g1.h"
 
 // Run the benchmark for `max_seconds` and return the time per iteration in nanoseconds.
 long run_bench(int scale, int max_seconds) {
-    timespec t0, t1;
+    timespec_t t0, t1;
     unsigned long total_time = 0, nits = 0;
     FFTSettings fs;
 
     assert(C_KZG_OK == new_fft_settings(&fs, scale));
+
     // Allocate on the heap to avoid stack overflow for large sizes
     blst_p1 *data, *out;
     data = malloc(fs.max_width * sizeof(blst_p1));
@@ -51,11 +53,29 @@ long run_bench(int scale, int max_seconds) {
     return total_time / nits;
 }
 
-#define NSEC 1
+int main(int argc, char *argv[]) {
+    int nsec = 0;
 
-int main(void) {
-    printf("*** Benchmarking FFT_g1, %d second%s per test.\n", NSEC, NSEC == 1 ? "" : "s");
-    for (int scale = 4; scale < 16; scale++) {
-        printf("fft_g1/scale_%d %lu ns/op\n", scale, run_bench(scale, 1));
+    switch (argc) {
+    case 1:
+        nsec = NSEC;
+        break;
+    case 2:
+        nsec = atoi(argv[1]);
+        break;
+    default:
+        break;
+    };
+
+    if (nsec == 0) {
+        printf("Usage: %s [test time in seconds > 0]\n", argv[0]);
+        exit(EXIT_FAILURE);
     }
+
+    printf("*** Benchmarking FFT_g1, %d second%s per test.\n", nsec, nsec == 1 ? "" : "s");
+    for (int scale = 4; scale <= 15; scale++) {
+        printf("fft_g1/scale_%d %lu ns/op\n", scale, run_bench(scale, nsec));
+    }
+
+    return EXIT_SUCCESS;
 }