diff --git a/src/dump_atom.cpp b/src/dump_atom.cpp
index 0dbd3b3278..dd2ea7ee13 100644
--- a/src/dump_atom.cpp
+++ b/src/dump_atom.cpp
@@ -289,19 +289,21 @@ void DumpAtom::header_item(bigint ndump)
 {
   if (unit_flag && !unit_count) {
     ++unit_count;
-    fprintf(fp,"ITEM: UNITS\n%s\n",update->unit_style);
+    fmt::print(fp,"ITEM: UNITS\n{}\n",update->unit_style);
   }
-  if (time_flag) fprintf(fp,"ITEM: TIME\n%.16g\n",compute_time());
+  if (time_flag) fmt::print(fp,"ITEM: TIME\n{:.16}\n",compute_time());
 
-  fprintf(fp,"ITEM: TIMESTEP\n");
-  fprintf(fp,BIGINT_FORMAT "\n",update->ntimestep);
-  fprintf(fp,"ITEM: NUMBER OF ATOMS\n");
-  fprintf(fp,BIGINT_FORMAT "\n",ndump);
-  fprintf(fp,"ITEM: BOX BOUNDS %s\n",boundstr);
-  fprintf(fp,"%-1.16e %-1.16e\n",boxxlo,boxxhi);
-  fprintf(fp,"%-1.16e %-1.16e\n",boxylo,boxyhi);
-  fprintf(fp,"%-1.16e %-1.16e\n",boxzlo,boxzhi);
-  fprintf(fp,"ITEM: ATOMS %s\n",columns);
+  fmt::print(fp,"ITEM: TIMESTEP\n{}\n"
+             "ITEM: NUMBER OF ATOMS\n{}\n",
+             update->ntimestep, ndump);
+
+  fmt::print(fp,"ITEM: BOX BOUNDS {}\n"
+             "{:>1.16e} {:>1.16e}\n"
+             "{:>1.16e} {:>1.16e}\n"
+             "{:>1.16e} {:>1.16e}\n",
+             boundstr,boxxlo,boxxhi,boxylo,boxyhi,boxzlo,boxzhi);
+
+  fmt::print(fp,"ITEM: ATOMS {}\n",columns);
 }
 
 /* ---------------------------------------------------------------------- */
@@ -310,19 +312,21 @@ void DumpAtom::header_item_triclinic(bigint ndump)
 {
   if (unit_flag && !unit_count) {
     ++unit_count;
-    fprintf(fp,"ITEM: UNITS\n%s\n",update->unit_style);
+    fmt::print(fp,"ITEM: UNITS\n{}\n",update->unit_style);
   }
-  if (time_flag) fprintf(fp,"ITEM: TIME\n%.16g\n",compute_time());
+  if (time_flag) fmt::print(fp,"ITEM: TIME\n{:.16}\n",compute_time());
 
-  fprintf(fp,"ITEM: TIMESTEP\n");
-  fprintf(fp,BIGINT_FORMAT "\n",update->ntimestep);
-  fprintf(fp,"ITEM: NUMBER OF ATOMS\n");
-  fprintf(fp,BIGINT_FORMAT "\n",ndump);
-  fprintf(fp,"ITEM: BOX BOUNDS xy xz yz %s\n",boundstr);
-  fprintf(fp,"%-1.16e %-1.16e %-1.16e\n",boxxlo,boxxhi,boxxy);
-  fprintf(fp,"%-1.16e %-1.16e %-1.16e\n",boxylo,boxyhi,boxxz);
-  fprintf(fp,"%-1.16e %-1.16e %-1.16e\n",boxzlo,boxzhi,boxyz);
-  fprintf(fp,"ITEM: ATOMS %s\n",columns);
+  fmt::print(fp,"ITEM: TIMESTEP\n{}\n"
+             "ITEM: NUMBER OF ATOMS\n{}\n",
+             update->ntimestep, ndump);
+
+  fmt::print(fp,"ITEM: BOX BOUNDS xy xz yz {}\n"
+             "{:>1.16e} {:>1.16e} {:>1.16e}\n"
+             "{:>1.16e} {:>1.16e} {:>1.16e}\n"
+             "{:>1.16e} {:>1.16e} {:>1.16e}\n",
+             boundstr,boxxlo,boxxhi,boxxy,boxylo,boxyhi,boxxz,boxzlo,boxzhi,boxyz);
+
+  fmt::print(fp,"ITEM: ATOMS {}\n",columns);
 }
 
 /* ---------------------------------------------------------------------- */
diff --git a/src/dump_cfg.cpp b/src/dump_cfg.cpp
index d52dac745f..b1c9aed58b 100644
--- a/src/dump_cfg.cpp
+++ b/src/dump_cfg.cpp
@@ -123,7 +123,7 @@ void DumpCFG::write_header(bigint n)
   if (atom->peri_flag) scale = atom->pdscale;
   else if (unwrapflag == 1) scale = UNWRAPEXPAND;
 
-  fprintf(fp,"Number of particles = " BIGINT_FORMAT "\n", n);
+  fmt::print(fp,"Number of particles = {}\n", n);
   fprintf(fp,"A = %g Angstrom (basic length-scale)\n",scale);
   fprintf(fp,"H0(1,1) = %g A\n",domain->xprd);
   fprintf(fp,"H0(1,2) = 0 A \n");
diff --git a/src/dump_custom.cpp b/src/dump_custom.cpp
index 5d371d3145..e7371c1fe1 100644
--- a/src/dump_custom.cpp
+++ b/src/dump_custom.cpp
@@ -507,19 +507,21 @@ void DumpCustom::header_item(bigint ndump)
 {
   if (unit_flag && !unit_count) {
     ++unit_count;
-    fprintf(fp,"ITEM: UNITS\n%s\n",update->unit_style);
+    fmt::print(fp,"ITEM: UNITS\n{}\n",update->unit_style);
   }
-  if (time_flag) fprintf(fp,"ITEM: TIME\n%.16g\n",compute_time());
+  if (time_flag) fmt::print(fp,"ITEM: TIME\n{:.16}\n",compute_time());
 
-  fprintf(fp,"ITEM: TIMESTEP\n");
-  fprintf(fp,BIGINT_FORMAT "\n",update->ntimestep);
-  fprintf(fp,"ITEM: NUMBER OF ATOMS\n");
-  fprintf(fp,BIGINT_FORMAT "\n",ndump);
-  fprintf(fp,"ITEM: BOX BOUNDS %s\n",boundstr);
-  fprintf(fp,"%-1.16e %-1.16e\n",boxxlo,boxxhi);
-  fprintf(fp,"%-1.16e %-1.16e\n",boxylo,boxyhi);
-  fprintf(fp,"%-1.16e %-1.16e\n",boxzlo,boxzhi);
-  fprintf(fp,"ITEM: ATOMS %s\n",columns);
+  fmt::print(fp,"ITEM: TIMESTEP\n{}\n"
+             "ITEM: NUMBER OF ATOMS\n{}\n",
+             update->ntimestep, ndump);
+
+  fmt::print(fp,"ITEM: BOX BOUNDS {}\n"
+             "{:>1.16e} {:>1.16e}\n"
+             "{:>1.16e} {:>1.16e}\n"
+             "{:>1.16e} {:>1.16e}\n",
+             boundstr,boxxlo,boxxhi,boxylo,boxyhi,boxzlo,boxzhi);
+
+  fmt::print(fp,"ITEM: ATOMS {}\n",columns);
 }
 
 /* ---------------------------------------------------------------------- */
@@ -528,19 +530,21 @@ void DumpCustom::header_item_triclinic(bigint ndump)
 {
   if (unit_flag && !unit_count) {
     ++unit_count;
-    fprintf(fp,"ITEM: UNITS\n%s\n",update->unit_style);
+    fmt::print(fp,"ITEM: UNITS\n{}\n",update->unit_style);
   }
-  if (time_flag) fprintf(fp,"ITEM: TIME\n%.16g\n",compute_time());
+  if (time_flag) fmt::print(fp,"ITEM: TIME\n{:.16}\n",compute_time());
 
-  fprintf(fp,"ITEM: TIMESTEP\n");
-  fprintf(fp,BIGINT_FORMAT "\n",update->ntimestep);
-  fprintf(fp,"ITEM: NUMBER OF ATOMS\n");
-  fprintf(fp,BIGINT_FORMAT "\n",ndump);
-  fprintf(fp,"ITEM: BOX BOUNDS xy xz yz %s\n",boundstr);
-  fprintf(fp,"%-1.16e %-1.16e %-1.16e\n",boxxlo,boxxhi,boxxy);
-  fprintf(fp,"%-1.16e %-1.16e %-1.16e\n",boxylo,boxyhi,boxxz);
-  fprintf(fp,"%-1.16e %-1.16e %-1.16e\n",boxzlo,boxzhi,boxyz);
-  fprintf(fp,"ITEM: ATOMS %s\n",columns);
+  fmt::print(fp,"ITEM: TIMESTEP\n{}\n"
+             "ITEM: NUMBER OF ATOMS\n{}\n",
+             update->ntimestep, ndump);
+
+  fmt::print(fp,"ITEM: BOX BOUNDS xy xz yz {}\n"
+             "{:>1.16e} {:>1.16e} {:>1.16e}\n"
+             "{:>1.16e} {:>1.16e} {:>1.16e}\n"
+             "{:>1.16e} {:>1.16e} {:>1.16e}\n",
+             boundstr,boxxlo,boxxhi,boxxy,boxylo,boxyhi,boxxz,boxzlo,boxzhi,boxyz);
+
+  fmt::print(fp,"ITEM: ATOMS {}\n",columns);
 }
 
 /* ---------------------------------------------------------------------- */
diff --git a/src/dump_local.cpp b/src/dump_local.cpp
index 67586c625a..a5bc99d939 100644
--- a/src/dump_local.cpp
+++ b/src/dump_local.cpp
@@ -242,8 +242,7 @@ int DumpLocal::modify_param(int narg, char **arg)
       // use of &str[1] removes leading '%' from BIGINT_FORMAT string
       char *ptr = strchr(format_int_user,'d');
       if (ptr == nullptr)
-        error->all(FLERR,
-                   "Dump_modify int format does not contain d character");
+        error->all(FLERR, "Dump_modify int format does not contain d character");
       char str[8];
       sprintf(str,"%s",BIGINT_FORMAT);
       *ptr = '\0';
@@ -273,26 +272,29 @@ void DumpLocal::write_header(bigint ndump)
   if (me == 0) {
     if (unit_flag && !unit_count) {
       ++unit_count;
-      fprintf(fp,"ITEM: UNITS\n%s\n",update->unit_style);
+      fmt::print(fp,"ITEM: UNITS\n{}\n",update->unit_style);
     }
-    if (time_flag) fprintf(fp,"ITEM: TIME\n%.16g\n",compute_time());
+    if (time_flag) fmt::print(fp,"ITEM: TIME\n{:.16}\n",compute_time());
+
+    fmt::print(fp,"ITEM: TIMESTEP\n{}\n"
+               "ITEM: NUMBER OF {}\n{}\n",
+               update->ntimestep, label, ndump);
 
-    fprintf(fp,"ITEM: TIMESTEP\n");
-    fprintf(fp,BIGINT_FORMAT "\n",update->ntimestep);
-    fprintf(fp,"ITEM: NUMBER OF %s\n",label);
-    fprintf(fp,BIGINT_FORMAT "\n",ndump);
     if (domain->triclinic) {
-      fprintf(fp,"ITEM: BOX BOUNDS xy xz yz %s\n",boundstr);
-      fprintf(fp,"%-1.16e %-1.16e %-1.16e\n",boxxlo,boxxhi,boxxy);
-      fprintf(fp,"%-1.16e %-1.16e %-1.16e\n",boxylo,boxyhi,boxxz);
-      fprintf(fp,"%-1.16e %-1.16e %-1.16e\n",boxzlo,boxzhi,boxyz);
+      fmt::print(fp,"ITEM: BOX BOUNDS xy xz yz {}\n"
+                 "{:>1.16e} {:>1.16e} {:>1.16e}\n"
+                 "{:>1.16e} {:>1.16e} {:>1.16e}\n"
+                 "{:>1.16e} {:>1.16e} {:>1.16e}\n",
+                 boundstr,boxxlo,boxxhi,boxxy,boxylo,boxyhi,boxxz,boxzlo,boxzhi,boxyz);
     } else {
-      fprintf(fp,"ITEM: BOX BOUNDS %s\n",boundstr);
-      fprintf(fp,"%-1.16e %-1.16e\n",boxxlo,boxxhi);
-      fprintf(fp,"%-1.16e %-1.16e\n",boxylo,boxyhi);
-      fprintf(fp,"%-1.16e %-1.16e\n",boxzlo,boxzhi);
+      fmt::print(fp,"ITEM: BOX BOUNDS {}\n"
+                 "{:>1.16e} {:>1.16e}\n"
+                 "{:>1.16e} {:>1.16e}\n"
+                 "{:>1.16e} {:>1.16e}\n",
+                 boundstr,boxxlo,boxxhi,boxylo,boxyhi,boxzlo,boxzhi);
     }
-    fprintf(fp,"ITEM: %s %s\n",label,columns);
+    
+    fmt::print(fp,"ITEM: {} {}\n", label, columns);
   }
 }
 
diff --git a/src/fix_ave_chunk.cpp b/src/fix_ave_chunk.cpp
index b6cb17b8c9..efe1bd9fdc 100644
--- a/src/fix_ave_chunk.cpp
+++ b/src/fix_ave_chunk.cpp
@@ -941,7 +941,7 @@ void FixAveChunk::end_of_step()
     if (overwrite) platform::fseek(fp,filepos);
     double count = 0.0;
     for (m = 0; m < nchunk; m++) count += count_total[m];
-    fprintf(fp,BIGINT_FORMAT " %d %g\n",ntimestep,nchunk,count);
+    fmt::print(fp,"{} {} {}\n",ntimestep,nchunk,count);
 
     int compress = cchunk->compress;
     int *chunkID = cchunk->chunkID;
diff --git a/src/fix_ave_correlate.cpp b/src/fix_ave_correlate.cpp
index 486b991b77..17182c8667 100644
--- a/src/fix_ave_correlate.cpp
+++ b/src/fix_ave_correlate.cpp
@@ -487,7 +487,7 @@ void FixAveCorrelate::end_of_step()
   if (fp && me == 0) {
     clearerr(fp);
     if (overwrite) platform::fseek(fp,filepos);
-    fprintf(fp,BIGINT_FORMAT " %d\n",ntimestep,nrepeat);
+    fmt::print(fp,"{} {}\n",ntimestep,nrepeat);
     for (i = 0; i < nrepeat; i++) {
       fprintf(fp,"%d %d %d",i+1,i*nevery,count[i]);
       if (count[i])
diff --git a/src/fix_ave_histo.cpp b/src/fix_ave_histo.cpp
index 5a7c6d4ccb..c2acd652ad 100644
--- a/src/fix_ave_histo.cpp
+++ b/src/fix_ave_histo.cpp
@@ -815,7 +815,7 @@ void FixAveHisto::end_of_step()
   if (fp && me == 0) {
     clearerr(fp);
     if (overwrite) platform::fseek(fp,filepos);
-    fprintf(fp,BIGINT_FORMAT " %d %g %g %g %g\n",ntimestep,nbins,
+    fmt::print(fp,"{} {} {} {} {} {}\n",ntimestep,nbins,
             stats_total[0],stats_total[1],stats_total[2],stats_total[3]);
     if (stats_total[0] != 0.0)
       for (i = 0; i < nbins; i++)
diff --git a/src/fix_ave_histo_weight.cpp b/src/fix_ave_histo_weight.cpp
index 16a64e093e..f90551b52f 100644
--- a/src/fix_ave_histo_weight.cpp
+++ b/src/fix_ave_histo_weight.cpp
@@ -468,7 +468,7 @@ void FixAveHistoWeight::end_of_step()
   if (fp && me == 0) {
     clearerr(fp);
     if (overwrite) platform::fseek(fp,filepos);
-    fprintf(fp,BIGINT_FORMAT " %d %g %g %g %g\n",ntimestep,nbins,
+    fmt::print(fp,"{} {} {} {} {} {}\n",ntimestep,nbins,
             stats_total[0],stats_total[1],stats_total[2],stats_total[3]);
     if (stats_total[0] != 0.0)
       for (i = 0; i < nbins; i++)
diff --git a/src/fix_ave_time.cpp b/src/fix_ave_time.cpp
index 98b066ef0b..ee08c859f4 100644
--- a/src/fix_ave_time.cpp
+++ b/src/fix_ave_time.cpp
@@ -669,11 +669,10 @@ void FixAveTime::invoke_scalar(bigint ntimestep)
   if (fp && me == 0) {
     clearerr(fp);
     if (overwrite) platform::fseek(fp,filepos);
-    fprintf(fp,BIGINT_FORMAT,ntimestep);
+    fmt::print(fp,"{}",ntimestep);
     for (i = 0; i < nvalues; i++) fprintf(fp,format,vector_total[i]/norm);
     fprintf(fp,"\n");
-    if (ferror(fp))
-      error->one(FLERR,"Error writing out time averaged data");
+    if (ferror(fp)) error->one(FLERR,"Error writing out time averaged data");
 
     fflush(fp);
 
@@ -881,7 +880,7 @@ void FixAveTime::invoke_vector(bigint ntimestep)
 
   if (fp && me == 0) {
     if (overwrite) platform::fseek(fp,filepos);
-    fprintf(fp,BIGINT_FORMAT " %d\n",ntimestep,nrows);
+    fmt::print(fp,"{} {}\n",ntimestep,nrows);
     for (i = 0; i < nrows; i++) {
       fprintf(fp,"%d",i+1);
       for (j = 0; j < nvalues; j++) fprintf(fp,format,array_total[i][j]/norm);
diff --git a/src/fix_property_atom.cpp b/src/fix_property_atom.cpp
index f7b9662c24..0e91a5f3fb 100644
--- a/src/fix_property_atom.cpp
+++ b/src/fix_property_atom.cpp
@@ -445,34 +445,35 @@ void FixPropertyAtom::write_data_section(int /*mth*/, FILE *fp,
                                          int n, double **buf, int /*index*/)
 {
   int k,icol,ncol,nv;
+  std::string line;
 
   for (int i = 0; i < n; i++) {
-    fprintf(fp,TAGINT_FORMAT,(tagint) ubuf(buf[i][0]).i);
+    line = fmt::format("{}",(tagint) ubuf(buf[i][0]).i);
     icol = 1;
     for (nv = 0; nv < nvalue; nv++) {
       if (styles[nv] == MOLECULE)
-        fprintf(fp," " TAGINT_FORMAT,(tagint) ubuf(buf[i][icol++]).i);
+        line += fmt::format(" {}",(tagint) ubuf(buf[i][icol++]).i);
       else if (styles[nv] == CHARGE)
-        fprintf(fp," %g",buf[i][icol++]);
+        line += fmt::format(" {}",buf[i][icol++]);
       else if (styles[nv] == RMASS)
-        fprintf(fp," %g",buf[i][icol++]);
+        line += fmt::format(" {}",buf[i][icol++]);
       else if (styles[nv] == IVEC)
-        fprintf(fp," %d",(int) ubuf(buf[i][icol++]).i);
+        line += fmt::format(" {}",(int) ubuf(buf[i][icol++]).i);
       else if (styles[nv] == DVEC)
-        fprintf(fp," %g",buf[i][icol++]);
+        line += fmt::format(" {}",buf[i][icol++]);
       else if (styles[nv] == IARRAY) {
         ncol = cols[nv];
         for (k = 0; k < ncol; k++)
-          fprintf(fp," %d",(int) ubuf(buf[i][icol+k]).i);
+          line += fmt::format(" {}",(int) ubuf(buf[i][icol+k]).i);
         icol += ncol;
       } else if (styles[nv] == DARRAY) {
         ncol = cols[nv];
         for (k = 0; k < ncol; k++)
-          fprintf(fp," %g",buf[i][icol+k]);
+          line += fmt::format(" {}",buf[i][icol+k]);
         icol += ncol;
       }
     }
-    fprintf(fp,"\n");
+    fmt::print(fp,line+"\n");
   }
 }