diff --git a/TODO b/TODO
index 63ebaf48..8d5a3d74 100644
--- a/TODO
+++ b/TODO
@@ -9,6 +9,8 @@
 
   displacement error, I guess?
 
+  yes, reduceh output should move one to the right
+
 - need more tests for reduce, test every kernel plus every numeric type
 
 - try orc version of reducev? and shrinkv? maybe shrinkh?
diff --git a/libvips/resample/reduceh.cpp b/libvips/resample/reduceh.cpp
index 81b447b6..de556ae4 100644
--- a/libvips/resample/reduceh.cpp
+++ b/libvips/resample/reduceh.cpp
@@ -496,7 +496,7 @@ vips_reduceh_build( VipsObject *object )
 	/* Add new pixels around the input so we can interpolate at the edges.
 	 */
 	if( vips_embed( in, &t[1], 
-		reduceh->n_points / 2, 0, 
+		reduceh->n_points / 2 - 1, 0, 
 		in->Xsize + reduceh->n_points - 1, in->Ysize,
 		"extend", VIPS_EXTEND_COPY,
 		NULL ) )
@@ -507,14 +507,14 @@ vips_reduceh_build( VipsObject *object )
 		VIPS_DEMAND_STYLE_THINSTRIP, in, NULL ) )
 		return( -1 );
 
-	/* Size output. Note: we round the output width down!
+	/* Size output. Note: we round to nearest to hide rounding errors. 
 	 *
 	 * Don't change xres/yres, leave that to the application layer. For
 	 * example, vipsthumbnail knows the true reduce factor (including the
 	 * fractional part), we just see the integer part here.
 	 */
-	resample->out->Xsize = (in->Xsize - reduceh->n_points + 1) / 
-		reduceh->xshrink;
+	resample->out->Xsize = VIPS_RINT( 
+		(in->Xsize - reduceh->n_points + 1) / reduceh->xshrink );
 	if( resample->out->Xsize <= 0 ) { 
 		vips_error( object_class->nickname, 
 			"%s", _( "image has shrunk to nothing" ) );
diff --git a/libvips/resample/reducev.cpp b/libvips/resample/reducev.cpp
index 6dd1537f..b5bd652d 100644
--- a/libvips/resample/reducev.cpp
+++ b/libvips/resample/reducev.cpp
@@ -411,7 +411,7 @@ vips_reducev_build( VipsObject *object )
 	/* Add new pixels around the input so we can interpolate at the edges.
 	 */
 	if( vips_embed( in, &t[1], 
-		0, reducev->n_points / 2, 
+		0, reducev->n_points / 2 - 1, 
 		in->Xsize, in->Ysize + reducev->n_points - 1, 
 		"extend", VIPS_EXTEND_COPY,
 		NULL ) )
@@ -422,13 +422,14 @@ vips_reducev_build( VipsObject *object )
 		VIPS_DEMAND_STYLE_SMALLTILE, in, NULL ) )
 		return( -1 );
 
-	/* Size output. Note: we round the output width down!
+	/* Size output. Note: we round to nearest to hide rounding errors. 
 	 *
 	 * Don't change xres/yres, leave that to the application layer. For
 	 * example, vipsthumbnail knows the true reduce factor (including the
 	 * fractional part), we just see the integer part here.
 	 */
-	resample->out->Ysize = (in->Ysize - reducev->n_points + 1) / reducev->yshrink;
+	resample->out->Ysize = VIPS_RINT( 
+		(in->Ysize - reducev->n_points + 1) / reducev->yshrink );
 	if( resample->out->Ysize <= 0 ) { 
 		vips_error( object_class->nickname, 
 			"%s", _( "image has shrunk to nothing" ) );
diff --git a/libvips/resample/resize.c b/libvips/resample/resize.c
index 590227b8..fc9651d5 100644
--- a/libvips/resample/resize.c
+++ b/libvips/resample/resize.c
@@ -135,13 +135,11 @@ vips_resize_build( VipsObject *object )
 	/* Do we need a further size adjustment? It's the difference
 	 * between our target size and the size we have after vips_shrink().
 	 *
-	 * Aim for a little above target so we can't round down below it.
-	 *
 	 * This can break the aspect ratio slightly :/ but hopefully no one
 	 * will notice.
 	 */
-	hresidual = ((double) target_width + 0.1) / in->Xsize;
-	vresidual = ((double) target_height + 0.1) / in->Ysize;
+	hresidual = (double) target_width / in->Xsize;
+	vresidual = (double) target_height / in->Ysize;
 
 	/* We want to make sure we read the image sequentially.
 	 * However, the convolution we may be doing later will force us 
diff --git a/tools/vipsthumbnail.c b/tools/vipsthumbnail.c
index f44dd206..a507d568 100644
--- a/tools/vipsthumbnail.c
+++ b/tools/vipsthumbnail.c
@@ -185,14 +185,13 @@ calculate_shrink( VipsImage *im )
 	VipsDirection direction;
 
 	/* Calculate the horizontal and vertical shrink we'd need to fit the
-	 * image to the bounding box, and pick the biggest. Aim for a little 
-	 * above the target so we can't round down below it. 
+	 * image to the bounding box, and pick the biggest. 
 	 *
 	 * In crop mode we aim to fill the bounding box, so we must use the
 	 * smaller axis.
 	 */
-	double horizontal = (double) width / (thumbnail_width + 0.1);
-	double vertical = (double) height / (thumbnail_height + 0.1);
+	double horizontal = (double) width / thumbnail_width;
+	double vertical = (double) height / thumbnail_height;
 
 	if( crop_image ) {
 		if( horizontal < vertical )
@@ -470,10 +469,7 @@ thumbnail_shrink( VipsObject *process, VipsImage *in )
 
 	shrink = calculate_shrink( in );
 
-	/* Add a tiny amount to stop rounding below the target.
-	 */
-	if( vips_resize( in, &t[4], 1.0 / shrink + 0.0000000001, 
-		NULL ) ) 
+	if( vips_resize( in, &t[4], 1.0 / shrink, NULL ) ) 
 		return( NULL );
 	in = t[4];