diff --git a/src/kiri/core/conf.js b/src/kiri/core/conf.js
index b8f5ffb4..5ac17300 100644
--- a/src/kiri/core/conf.js
+++ b/src/kiri/core/conf.js
@@ -263,6 +263,7 @@ export const conf = {
                 firstLayerBedTemp: 0,
                 firstLayerBeltBump: 0,
                 firstLayerBeltLead: 3,
+                firstLayerBeltFact: 1,
                 firstLayerBrim: 0,
                 firstLayerBrimGap: 0,
                 firstLayerBrimIn: 0,
diff --git a/src/kiri/mode/fdm/init-menu.js b/src/kiri/mode/fdm/init-menu.js
index 453d83da..715ce191 100644
--- a/src/kiri/mode/fdm/init-menu.js
+++ b/src/kiri/mode/fdm/init-menu.js
@@ -134,6 +134,7 @@ export function menu() {
     firstLayerFanSpeed:  newInput(LANG.ou_fans_s, {title:LANG.ou_fans_l, convert:toInt,   bound:bound(0,255), show:isBelt}),
     firstLayerYOffset:   newInput(LANG.fl_zoff_s, {title:LANG.fl_zoff_l, convert:toFloat, show:isBelt}),
     firstLayerFlatten:   newInput(LANG.fl_flat_s, {title:LANG.fl_flat_l, convert:toFloat, show:isBelt}),
+    firstLayerBeltFact:  newInput(LANG.fl_mult_s, {title:LANG.fl_mult_l, convert:toFloat, bound:bound(0, 2), show:isBelt}),
     firstLayerRate:      newInput(LANG.fl_rate_s, {title:LANG.fl_rate_l, convert:toFloat}),
     firstLayerFillRate:  newInput(LANG.fl_frat_s, {title:LANG.fl_frat_l, convert:toFloat, show:isNotBelt}),
     separator:           newBlank({ class:"set-sep", driven, show:isBelt }),
diff --git a/src/kiri/mode/fdm/prepare.js b/src/kiri/mode/fdm/prepare.js
index 680cc075..8fd835b3 100644
--- a/src/kiri/mode/fdm/prepare.js
+++ b/src/kiri/mode/fdm/prepare.js
@@ -682,6 +682,7 @@ export async function fdm_prepare(widgets, settings, update) {
 
             for (let rec of layer) {
                 overate = rec.overate >= 0 ? rec.overate : overate;
+                let bmult = params.firstLayerBeltFact ?? 1;
                 let brate = params.firstLayerRate || firstLayerRate;
                 let point = rec.point;
                 let belty = rec.belty = -point.y + (point.z * belt.slope);
@@ -695,6 +696,8 @@ export async function fdm_prepare(widgets, settings, update) {
                     // apply base speed to segments touching belt
                     rec.speed = params.firstLayerRate || Math.min(rec.speed, lowrate);
                     rec.fan = params.firstLayerFanSpeed;
+                    // apply base flowrate multiplier to segments touching belt
+                    rec.emit *= bmult;
                     minx = Math.min(minx, point.x, lastout.point.x);
                     maxx = Math.max(maxx, point.x, lastout.point.x);
                     maxy = Math.max(maxy, point.y);