{"id":200,"date":"2026-06-30T09:02:11","date_gmt":"2026-06-30T08:02:11","guid":{"rendered":"https:\/\/askthenozzle.com\/blog\/how-to-fix-under-extrusion-the-settings-and-order-that-actually-work\/"},"modified":"2026-07-06T09:03:34","modified_gmt":"2026-07-06T08:03:34","slug":"how-to-fix-under-extrusion-the-settings-and-order-that-actually-work","status":"publish","type":"post","link":"https:\/\/askthenozzle.com\/blog\/how-to-fix-under-extrusion-the-settings-and-order-that-actually-work\/","title":{"rendered":"How to Fix Under-Extrusion: The Settings (and Order) That Actually Work"},"content":{"rendered":"<p>Under-extrusion is one of the most common \u2014 and most misdiagnosed \u2014 FDM problems. It happens when your printer doesn&#8217;t push enough filament to fill the layers it&#8217;s been told to lay down, leaving thin, weak walls, visible gaps between perimeters, and a rough, patchy surface. The good news: it&#8217;s rarely a sign of a serious hardware fault. The bad news: it has a long list of possible causes, which is exactly why people burn an afternoon changing random sliders. This guide gives you the right way to <strong>fix under-extrusion settings<\/strong> \u2014 in the correct order, with concrete values you can act on today.<\/p>\n<p>If you&#8217;d rather just upload a photo of the failure and get back exact slicer settings, that&#8217;s what our <a href=\"https:\/\/askthenozzle.com\/diagnose\">Diagnose tool<\/a> is built for. But if you want to understand and fix it yourself, read on.<\/p>\n<h2>How to spot under-extrusion (and rule out other faults)<\/h2>\n<p>Before you touch a single setting, confirm you&#8217;re actually looking at under-extrusion. The classic signs are:<\/p>\n<ul>\n<li>Thin, weak walls that flex or split along layer lines<\/li>\n<li>Visible gaps between adjacent extrusion lines, especially on top layers<\/li>\n<li>Sparse, broken extrusion that doesn&#8217;t fully fill the perimeter<\/li>\n<\/ul>\n<p>A quick, reliable test: print a small calibration cube and hold one wall up to a bright light. If you can see pinholes or gaps between the lines, you&#8217;re under-extruding and likely need a marginal flow increase. If you&#8217;re not sure whether you&#8217;re chasing under-extrusion or something else entirely, our broader guide on <a href=\"https:\/\/askthenozzle.com\/blog\/why-is-my-3d-print-failing-the-real-causes-and-exact-fixes\/\">why prints fail<\/a> and the <a href=\"https:\/\/askthenozzle.com\/blog\/3d-print-defect-identification-tool-how-to-spot-diagnose-and-fix-fdm-failures-fast\/\">defect identification tool<\/a> will help you name the defect before you fix it.<\/p>\n<h2>Fix it in the right order \u2014 or get misleading results<\/h2>\n<p>This is the part most tutorials get wrong. Calibrating in the wrong sequence gives you numbers that look right but don&#8217;t hold up. Work through it like this:<\/p>\n<ol>\n<li><strong>Rule out mechanical issues first.<\/strong> If your printer was fine yesterday and under-extrudes today, your E-steps didn&#8217;t magically change. The cause is mechanical \u2014 a partially clogged nozzle, heat creep, or a worn\/slipping extruder. Calibrating software values to mask a mechanical fault is a band-aid that will fail again. Fix the hardware, then calibrate.<\/li>\n<li><strong>E-steps next.<\/strong> Get extruder steps-per-mm within 1\u20132% of correct. This is a firmware setting calibrated once per extruder.<\/li>\n<li><strong>Temperature before flow.<\/strong> Flow is highly sensitive to temperature, so run a temperature tower and lock in your ideal nozzle temp <em>before<\/em> you calibrate flow. Calibrate flow at the wrong temperature and every later number is wrong too.<\/li>\n<li><strong>Flow rate \/ extrusion multiplier last<\/strong>, calibrated per filament.<\/li>\n<\/ol>\n<h2>E-steps: fixing under-extrusion at the source<\/h2>\n<p>E-steps tells the printer how many motor steps equal 1&nbsp;mm of filament movement. If that number is off, every print under-extrudes (gaps, weak parts) or over-extrudes (blobs) regardless of slicer tweaks. Many Creality machines ship at <strong>93 steps\/mm<\/strong>, which is commonly slightly off \u2014 treat that as a typical default to check, not a universal truth.<\/p>\n<p>To calibrate:<\/p>\n<ol>\n<li>Heat the nozzle to printing temperature (e.g. 200&nbsp;\u00b0C for PLA). Cold extrusion gives false readings.<\/li>\n<li>Load filament and mark it exactly 120&nbsp;mm from where it enters the extruder body.<\/li>\n<li>Send <strong>M83<\/strong> (relative extrusion), then <strong>G1 E100 F100<\/strong> to extrude 100&nbsp;mm slowly.<\/li>\n<li>Measure the remaining distance to your mark. If the printer didn&#8217;t pull exactly 100&nbsp;mm, recalculate and update your E-steps, then save.<\/li>\n<\/ol>\n<p>The distinction matters: <strong>E-steps is a firmware setting that accounts for your extruder hardware. Flow rate is a per-filament slicer setting that accounts for filament diameter variation and material behaviour.<\/strong> They are not interchangeable.<\/p>\n<h2>Temperature: the most common easy fix<\/h2>\n<p>A nozzle that&#8217;s too cool can&#8217;t melt filament fast enough to push the required volume \u2014 a classic, easily-resolved cause of under-extrusion. Adjust in <strong>5 to 10&nbsp;\u00b0C<\/strong> steps and watch the result. As rough reference ranges (always check the specific filament&#8217;s spec sheet): PLA typically prints at <strong>180\u2013220&nbsp;\u00b0C<\/strong> and ABS at <strong>230\u2013250&nbsp;\u00b0C<\/strong>.<\/p>\n<p>One thing makers often miss: nozzle material changes the numbers. <strong>Hardened steel nozzles don&#8217;t retain heat as well as brass<\/strong>, so they generally need a higher set temperature to extrude the same material cleanly. If you swapped to hardened steel for abrasive filament and started under-extruding, bump the temperature before blaming anything else.<\/p>\n<h2>Flow rate \/ extrusion multiplier: the core setting<\/h2>\n<p>This is the headline number people mean when they search for how to fix under-extrusion settings. Be aware the naming differs across slicers: PrusaSlicer and Simplify3D call it <strong>Extrusion Multiplier<\/strong>; Cura calls it <strong>Flow<\/strong> (and confusingly uses &#8220;flow&#8221; for its volumetric preview too \u2014 a separate concept).<\/p>\n<p>At 100% the printer extrudes the calculated amount. Calibrating it corrects for small filament-diameter variations so you don&#8217;t under- or over-extrude. Usual working values sit between <strong>90 and 110<\/strong>, though you&#8217;re not forbidden from going outside that. Crucially, this is a <strong>per-filament<\/strong> setting: tune it at minimum per brand and material type. It can even vary by colour or by spool, depending on how consistent your supplier is.<\/p>\n<p>For a quick fix, increase flow by <strong>5%<\/strong> at a time until the gaps close.<\/p>\n<h3>The proper flow calibration method<\/h3>\n<p>For accuracy, print a thin-walled, single-perimeter hollow cube:<\/p>\n<ol>\n<li>Set flow to 100% and disable retraction.<\/li>\n<li>Measure all four walls with calipers and average them.<\/li>\n<li>Apply the formula: <strong>New Flow = (Target Wall Thickness \u00f7 Measured Wall Thickness) \u00d7 Current Flow<\/strong>.<\/li>\n<li>Repeat until you&#8217;re within \u00b10.02&nbsp;mm of the target.<\/li>\n<\/ol>\n<p>That said \u2014 <strong>your eyes beat the maths<\/strong>. After the calculation, nudge flow up or down based on what the surface actually looks like. The formula gets you close; the print tells you the truth.<\/p>\n<h2>Other settings worth checking<\/h2>\n<p>If temperature, E-steps and flow are dialled in and you still see under-extrusion, look at print speed (too fast outruns the hotend&#8217;s melt rate \u2014 back it off in 10&nbsp;mm\/s steps), partial clogs, and a slipping or under-tensioned extruder gear. Heat creep on long retracts can also starve the nozzle. For neighbouring symptoms that often travel with under-extrusion, see our fixes for <a href=\"https:\/\/askthenozzle.com\/blog\/first-layer-not-sticking-the-real-causes-and-exact-fixes\/\">first layer adhesion<\/a> and <a href=\"https:\/\/askthenozzle.com\/blog\/petg-stringing-fix-the-orcaslicer-settings-that-actually-work\/\">PETG stringing<\/a>. Running your file through the <a href=\"https:\/\/askthenozzle.com\/preflight\">gcode pre-flight checklist<\/a> before you print is a cheap way to catch flow-related issues early.<\/p>\n<h2>FAQ<\/h2>\n<h3>Should I calibrate E-steps or flow rate first?<\/h3>\n<p>E-steps first, then temperature, then flow. E-steps corrects the extruder hardware; flow corrects per-filament variance. If you calibrate flow on top of wrong E-steps, you&#8217;re compensating for a hardware error with a slicer band-aid that will mislead you on every other filament.<\/p>\n<h3>What flow rate should I use to fix under-extrusion?<\/h3>\n<p>Most filaments land between 90 and 110% flow. If you&#8217;re under-extruding, raise it in 5% steps until the gaps close, then verify with a thin-wall calibration cube and your calipers. Tune it per filament brand and type.<\/p>\n<h3>Can low temperature cause under-extrusion?<\/h3>\n<p>Yes \u2014 it&#8217;s one of the most common causes. If the hotend can&#8217;t melt filament fast enough, it can&#8217;t push the required volume. Raise the nozzle temperature in 5\u201310&nbsp;\u00b0C steps, and remember hardened steel nozzles usually need to run hotter than brass.<\/p>\n<h3>Why does my printer under-extrude suddenly when it was fine before?<\/h3>\n<p>That&#8217;s almost always mechanical, not a calibration drift \u2014 a partial clog, heat creep, or a slipping extruder. Fix the hardware first. Re-calibrating settings to hide it just delays the next failure.<\/p>\n<p><strong>Related:<\/strong> <a href=\"https:\/\/askthenozzle.com\/blog\/how-to-fix-stringing-in-3d-prints-the-settings-that-actually-kill-the-wisps\/\">How to Fix Stringing in 3D Prints: The Settings That Actually Kill the Wisps<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Under-extrusion is one of the most common \u2014 and most misdiagnosed \u2014 FDM problems. It happens when your printer doesn&#8217;t push enough filament to fill the layers it&#8217;s been told to lay down, leaving thin, weak walls, visible \u2026<\/p>\n","protected":false},"author":1,"featured_media":199,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-200","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-uncategorised"],"_links":{"self":[{"href":"https:\/\/askthenozzle.com\/blog\/wp-json\/wp\/v2\/posts\/200","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/askthenozzle.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/askthenozzle.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/askthenozzle.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/askthenozzle.com\/blog\/wp-json\/wp\/v2\/comments?post=200"}],"version-history":[{"count":1,"href":"https:\/\/askthenozzle.com\/blog\/wp-json\/wp\/v2\/posts\/200\/revisions"}],"predecessor-version":[{"id":214,"href":"https:\/\/askthenozzle.com\/blog\/wp-json\/wp\/v2\/posts\/200\/revisions\/214"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/askthenozzle.com\/blog\/wp-json\/wp\/v2\/media\/199"}],"wp:attachment":[{"href":"https:\/\/askthenozzle.com\/blog\/wp-json\/wp\/v2\/media?parent=200"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/askthenozzle.com\/blog\/wp-json\/wp\/v2\/categories?post=200"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/askthenozzle.com\/blog\/wp-json\/wp\/v2\/tags?post=200"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}