diff --git a/dive.c b/dive.c
index 455b1288c..edcb130f4 100644
--- a/dive.c
+++ b/dive.c
@@ -549,7 +549,7 @@ static void sanitize_cylinder_type(cylinder_type_t *type)
 		volume_of_air = cuft_to_l(type->size.mliter);
 		/* milliliters at 1 atm: "true size" */
 		volume = volume_of_air / surface_volume_multiplier(type->workingpressure);
-		type->size.mliter = volume + 0.5;
+		type->size.mliter = rint(volume);
 	}
 
 	/* Ok, we have both size and pressure: try to match a description */
diff --git a/dive.h b/dive.h
index 658b199fe..16105e1ec 100644
--- a/dive.h
+++ b/dive.h
@@ -155,7 +155,7 @@ static inline double grams_to_lbs(int grams)
 
 static inline int lbs_to_grams(double lbs)
 {
-	return lbs * 453.6 + 0.5;
+	return rint(lbs * 453.6);
 }
 
 static inline double ml_to_cuft(int ml)
@@ -175,12 +175,12 @@ static inline double mm_to_feet(int mm)
 
 static inline unsigned long feet_to_mm(double feet)
 {
-	return feet * 304.8 + 0.5;
+	return rint(feet * 304.8);
 }
 
 static inline int to_feet(depth_t depth)
 {
-	return mm_to_feet(depth.mm) + 0.5;
+	return rint(mm_to_feet(depth.mm));
 }
 
 static inline double mkelvin_to_C(int mkelvin)
@@ -195,12 +195,12 @@ static inline double mkelvin_to_F(int mkelvin)
 
 static inline unsigned long F_to_mkelvin(double f)
 {
-	return (f-32) * 1000 / 1.8 + ZERO_C_IN_MKELVIN + 0.5;
+	return rint((f-32) * 1000 / 1.8 + ZERO_C_IN_MKELVIN);
 }
 
 static inline unsigned long C_to_mkelvin(double c)
 {
-	return c * 1000 + ZERO_C_IN_MKELVIN + 0.5;
+	return rint(c * 1000 + ZERO_C_IN_MKELVIN);
 }
 
 static inline double psi_to_bar(double psi)
@@ -210,12 +210,12 @@ static inline double psi_to_bar(double psi)
 
 static inline long psi_to_mbar(double psi)
 {
-	return psi_to_bar(psi)*1000 + 0.5;
+	return rint(psi_to_bar(psi)*1000);
 }
 
 static inline int to_PSI(pressure_t pressure)
 {
-	return pressure.mbar * 0.0145037738 + 0.5;
+	return rint(pressure.mbar * 0.0145037738);
 }
 
 static inline double bar_to_atm(double bar)
@@ -446,7 +446,7 @@ static inline int calculate_depth_to_mbar(int depth, pressure_t surface_pressure
 	if (!salinity)
 		salinity = SEAWATER_SALINITY;
 	specific_weight = salinity / 10000.0 * 0.981;
-	mbar += depth / 10.0 * specific_weight + 0.5;
+	mbar += rint(depth / 10.0 * specific_weight);
 	return mbar;
 }
 
@@ -471,7 +471,7 @@ static inline int rel_mbar_to_depth(int mbar, struct dive *dive)
 	if (dive->dc.salinity)
 		specific_weight = dive->dc.salinity / 10000.0 * 0.981;
 	/* whole mbar gives us cm precision */
-	cm = mbar / specific_weight + 0.5;
+	cm = rint(mbar / specific_weight);
 	return cm * 10;
 }
 
diff --git a/divelist.c b/divelist.c
index a9a2b451c..9dc4b9438 100644
--- a/divelist.c
+++ b/divelist.c
@@ -226,7 +226,7 @@ static int calculate_otu(struct dive *dive)
 		if (po2 >= 500)
 			otu += pow((po2 - 500) / 1000.0, 0.83) * t / 30.0;
 	}
-	return otu + 0.5;
+	return rint(otu);
 }
 /* calculate CNS for a dive - this only takes the first divecomputer into account */
 int const cns_table[][3] = {
diff --git a/libdivecomputer.c b/libdivecomputer.c
index f93b2c0fc..7cc3894f9 100644
--- a/libdivecomputer.c
+++ b/libdivecomputer.c
@@ -77,13 +77,13 @@ static bool get_tanksize(device_data_t *devdata, const unsigned char *data, cyli
 		case COBALT_CFATPSI:
 			airvolume = cuft_to_l(atomics_gas_info[idx].tanksize) * 1000.0;
 			mbar = psi_to_mbar(atomics_gas_info[idx].workingpressure);
-			cyl[idx].type.size.mliter = airvolume / bar_to_atm(mbar / 1000.0) + 0.5;
+			cyl[idx].type.size.mliter = rint(airvolume / bar_to_atm(mbar / 1000.0));
 			cyl[idx].type.workingpressure.mbar = mbar;
 			break;
 		case COBALT_CFATBAR:
 			airvolume = cuft_to_l(atomics_gas_info[idx].tanksize) * 1000.0;
 			mbar = atomics_gas_info[idx].workingpressure * 1000;
-			cyl[idx].type.size.mliter = airvolume / bar_to_atm(mbar / 1000.0) + 0.5;
+			cyl[idx].type.size.mliter = rint(airvolume / bar_to_atm(mbar / 1000.0));
 			cyl[idx].type.workingpressure.mbar = mbar;
 			break;
 		case COBALT_WETINDL:
@@ -112,8 +112,8 @@ static int parse_gasmixes(device_data_t *devdata, struct dive *dive, dc_parser_t
 		if (i >= MAX_CYLINDERS)
 			continue;
 
-		o2 = gasmix.oxygen * 1000 + 0.5;
-		he = gasmix.helium * 1000 + 0.5;
+		o2 = rint(gasmix.oxygen * 1000);
+		he = rint(gasmix.helium * 1000);
 
 		/* Ignore bogus data - libdivecomputer does some crazy stuff */
 		if (o2 + he <= O2_IN_AIR || o2 >= 1000)
@@ -204,11 +204,11 @@ sample_cb(dc_sample_type_t type, dc_sample_value_t value, void *userdata)
 		finish_sample(dc);
 		break;
 	case DC_SAMPLE_DEPTH:
-		sample->depth.mm = value.depth * 1000 + 0.5;
+		sample->depth.mm = rint(value.depth * 1000);
 		break;
 	case DC_SAMPLE_PRESSURE:
 		sample->sensor = value.pressure.tank;
-		sample->cylinderpressure.mbar = value.pressure.value * 1000 + 0.5;
+		sample->cylinderpressure.mbar = rint(value.pressure.value * 1000);
 		break;
 	case DC_SAMPLE_TEMPERATURE:
 		sample->temperature.mkelvin = C_to_mkelvin(value.temperature);
@@ -235,28 +235,28 @@ sample_cb(dc_sample_type_t type, dc_sample_value_t value, void *userdata)
 #if DC_VERSION_CHECK(0, 3, 0)
 	case DC_SAMPLE_SETPOINT:
 		/* for us a setpoint means constant pO2 from here */
-		sample->po2 = po2 = value.setpoint * 1000 + 0.5;
+		sample->po2 = po2 = rint(value.setpoint * 1000);
 		break;
 	case DC_SAMPLE_PPO2:
-		sample->po2 = po2 = value.ppo2 * 1000 + 0.5;
+		sample->po2 = po2 = rint(value.ppo2 * 1000);
 		break;
 	case DC_SAMPLE_CNS:
-		sample->cns = cns = value.cns * 100 + 0.5;
+		sample->cns = cns = rint(value.cns * 100);
 		break;
 	case DC_SAMPLE_DECO:
 		if (value.deco.type == DC_DECO_NDL) {
 			sample->ndl.seconds = ndl = value.deco.time;
-			sample->stopdepth.mm = stopdepth = value.deco.depth * 1000.0 + 0.5;
+			sample->stopdepth.mm = stopdepth = rint(value.deco.depth * 1000.0);
 			sample->in_deco = in_deco = false;
 		} else if (value.deco.type == DC_DECO_DECOSTOP ||
 			   value.deco.type == DC_DECO_DEEPSTOP) {
 			sample->in_deco = in_deco = true;
-			sample->stopdepth.mm = stopdepth = value.deco.depth * 1000.0 + 0.5;
+			sample->stopdepth.mm = stopdepth = rint(value.deco.depth * 1000.0);
 			sample->stoptime.seconds = stoptime = value.deco.time;
 			ndl = 0;
 		} else if (value.deco.type == DC_DECO_SAFETYSTOP) {
 			sample->in_deco = in_deco = false;
-			sample->stopdepth.mm = stopdepth = value.deco.depth * 1000.0 + 0.5;
+			sample->stopdepth.mm = stopdepth = rint(value.deco.depth * 1000.0);
 			sample->stoptime.seconds = stoptime = value.deco.time;
 		}
 #endif
@@ -451,7 +451,7 @@ static int dive_cb(const unsigned char *data, unsigned int size,
 		dc_parser_destroy(parser);
 		return false;
 	}
-	dive->dc.maxdepth.mm = maxdepth * 1000 + 0.5;
+	dive->dc.maxdepth.mm = rint(maxdepth * 1000);
 
 	// Parse the gas mixes.
 	unsigned int ngases = 0;
@@ -474,7 +474,7 @@ static int dive_cb(const unsigned char *data, unsigned int size,
 		dc_parser_destroy(parser);
 		return false;
 	}
-	dive->dc.salinity = salinity.density * 10.0 + 0.5;
+	dive->dc.salinity = rint(salinity.density * 10.0);
 
 	double surface_pressure = 0;
 	rc = dc_parser_get_field(parser, DC_FIELD_ATMOSPHERIC, 0, &surface_pressure);
@@ -483,7 +483,7 @@ static int dive_cb(const unsigned char *data, unsigned int size,
 		dc_parser_destroy(parser);
 		return false;
 	}
-	dive->dc.surface_pressure.mbar = surface_pressure * 1000.0 + 0.5;
+	dive->dc.surface_pressure.mbar = rint(surface_pressure * 1000.0);
 #endif
 
 	rc = parse_gasmixes(devdata, dive, parser, ngases, data);
diff --git a/parse-xml.c b/parse-xml.c
index 3c536ed4b..2a98d3904 100644
--- a/parse-xml.c
+++ b/parse-xml.c
@@ -326,7 +326,7 @@ static void pressure(char *buffer, void *_press)
 			break;
 		}
 		if (mbar > 5 && mbar < 500000) {
-			pressure->mbar = mbar + 0.5;
+			pressure->mbar = rint(mbar);
 			break;
 		}
 	/* fallthrough */
@@ -341,7 +341,7 @@ static void salinity(char *buffer, void *_salinity)
 	union int_or_float val;
 	switch (integer_or_float(buffer, &val)) {
 	case FLOAT:
-		*salinity = val.fp * 10.0 + 0.5;
+		*salinity = rint(val.fp * 10.0);
 		break;
 	default:
 		printf("Strange salinity reading %s\n", buffer);
@@ -357,7 +357,7 @@ static void depth(char *buffer, void *_depth)
 	case FLOAT:
 		switch (xml_parsing_units.length) {
 		case METERS:
-			depth->mm = val.fp * 1000 + 0.5;
+			depth->mm = rint(val.fp * 1000);
 			break;
 		case FEET:
 			depth->mm = feet_to_mm(val.fp);
@@ -378,7 +378,7 @@ static void weight(char *buffer, void *_weight)
 	case FLOAT:
 		switch (xml_parsing_units.weight) {
 		case KG:
-			weight->grams = val.fp * 1000 + 0.5;
+			weight->grams = rint(val.fp * 1000);
 			break;
 		case LBS:
 			weight->grams = lbs_to_grams(val.fp);
@@ -472,7 +472,7 @@ static void percent(char *buffer, void *_fraction)
 
 		/* Then turn percent into our integer permille format */
 		if (val >= 0 && val <= 100.0) {
-			fraction->permille = val * 10 + 0.5;
+			fraction->permille = rint(val * 10);
 			break;
 		}
 	default:
@@ -502,7 +502,7 @@ static void cylindersize(char *buffer, void *_volume)
 
 	switch (integer_or_float(buffer, &val)) {
 	case FLOAT:
-		volume->mliter = val.fp * 1000 + 0.5;
+		volume->mliter = rint(val.fp * 1000);
 		break;
 
 	default:
@@ -549,7 +549,7 @@ static void get_rating(char *buffer, void *_i)
 static void double_to_permil(char *buffer, void *_i)
 {
 	int *i = _i;
-	*i = ascii_strtod(buffer, NULL) * 1000.0 + 0.5;
+	*i = rint(ascii_strtod(buffer, NULL) * 1000.0);
 }
 
 static void hex_value(char *buffer, void *_i)
@@ -636,7 +636,7 @@ static void psi_or_bar(char *buffer, void *_pressure)
 		if (val.fp > 400)
 			pressure->mbar = psi_to_mbar(val.fp);
 		else
-			pressure->mbar = val.fp * 1000 + 0.5;
+			pressure->mbar = rint(val.fp * 1000);
 		break;
 	default:
 		fprintf(stderr, "Crazy Diving Log PSI reading %s\n", buffer);
diff --git a/profile.c b/profile.c
index 07328580f..bcf4fb183 100644
--- a/profile.c
+++ b/profile.c
@@ -627,7 +627,7 @@ static void fill_missing_tank_pressures(struct dive *dive, struct plot_info *pi,
 			magic = (interpolate.end - interpolate.start) / (double) interpolate.pressure_time;
 
 			/* Use that overall pressure change to update the current pressure */
-			cur_pr[cyl] = interpolate.start + magic * interpolate.acc_pressure_time + 0.5;
+			cur_pr[cyl] = rint(interpolate.start + magic * interpolate.acc_pressure_time);
 		}
 		INTERPOLATED_PRESSURE(entry) = cur_pr[cyl];
 	}
diff --git a/uemis-downloader.c b/uemis-downloader.c
index ceac29235..99a1a8bc8 100644
--- a/uemis-downloader.c
+++ b/uemis-downloader.c
@@ -65,7 +65,7 @@ static void uemis_ts(char *buffer, void *_when)
 /* float minutes */
 static void uemis_duration(char *buffer, duration_t *duration)
 {
-	duration->seconds = ascii_strtod(buffer, NULL) * 60 + 0.5;
+	duration->seconds = rint(ascii_strtod(buffer, NULL) * 60);
 }
 
 /* int cm */
diff --git a/uemis.c b/uemis.c
index 27e526f1d..c43606d9c 100644
--- a/uemis.c
+++ b/uemis.c
@@ -329,9 +329,9 @@ void uemis_parse_divelog_binary(char *base64, void *datap) {
 		 * we store the incorrect working pressure to get the SAC calculations "close"
 		 * but the user will have to correct this manually
 		 */
-		dive->cylinder[i].type.size.mliter = volume;
+		dive->cylinder[i].type.size.mliter = rint(volume);
 		dive->cylinder[i].type.workingpressure.mbar = 202600;
-		dive->cylinder[i].gasmix.o2.permille = *(uint8_t *)(data+120+25*(gasoffset + i)) * 10 + 0.5;
+		dive->cylinder[i].gasmix.o2.permille = *(uint8_t *)(data+120+25*(gasoffset + i)) * 10;
 		dive->cylinder[i].gasmix.he.permille = 0;
 	}
 	/* first byte of divelog data is at offset 0x123 */