diff --git a/doc/pic.ms b/doc/pic.ms
index 6d581ba..a0a77c7 100644
--- a/doc/pic.ms
+++ b/doc/pic.ms
@@ -1722,7 +1722,8 @@ GNU \fBgpic\fP also documents a one-argument form or rand,
 version.
 .PP
 The function \fBsprintf()\fP behaves like a C \fIsprintf\/\fP(3)
-function that only takes %, %e, %f, and %g format strings.
+function that only takes the format strings %e, %E, %f, %g and %G,
+as well as %% for printing a raw percent character.
 .
 .
 .NH 1
diff --git a/src/preproc/pic/pic.1.man b/src/preproc/pic/pic.1.man
index 847bbe3..85af1e7 100644
--- a/src/preproc/pic/pic.1.man
+++ b/src/preproc/pic/pic.1.man
@@ -906,6 +906,11 @@ this will produce the arguments formatted according to
 which should be a string as described in
 .BR printf (3)
 appropriate for the number of arguments supplied.
+Only the flags
+.B #-+ 0123456789.,
+and the formats
+.B eEfgG%
+are supported.
 .
 .
 .LP
diff --git a/src/preproc/pic/pic.ypp b/src/preproc/pic/pic.ypp
index 6afa2ab..2e5562e 100644
--- a/src/preproc/pic/pic.ypp
+++ b/src/preproc/pic/pic.ypp
@@ -1895,6 +1895,11 @@ char *do_sprintf(const char *form, const double *v, int nv)
   string one_format;
   while (*form) {
     if (*form == '%') {
+      if(form[1] == '%'){
+        result += '%';
+        form += 2;
+        continue;
+      }
       one_format += *form++;
       for (; *form != '\0' && strchr("#-+ 0123456789.", *form) != 0; form++)
 	one_format += *form;