This tool estimates how much filament your support structures will consume, so you can budget material and cost before you ever slice. It is especially useful for dual-material jobs where supports print in a separate, often pricier, dissolvable filament.
How it works
Support weight scales with two things: how much of the model needs supporting (driven by overhang severity) and how dense those supports are. The estimate is:
Support weight = model weight x baseRatio(overhang) x (density% / referenceDensity%)
Each overhang level carries a base support ratio calibrated to a 20% support density reference: gentle around 0.08, moderate around 0.20, severe around 0.45. The chosen density then scales that ratio linearly — 10% density halves it, 40% roughly doubles it.
Worked example
A 120 g moderate-overhang functional bracket, supported at 15% density:
- Base ratio (moderate) = 0.20 at the 20% reference
- Density scale =
15 / 20 = 0.75 - Support weight =
120 x 0.20 x 0.75 = 18g - At 22 per kg filament, supports cost about 0.40 (18/1000 x 22)
Total job weight is 120 + 18 = 138 g.
Why support density matters more than most settings
Support density has an almost linear effect on support material consumption. A model with severe overhangs (the kind that really need support) at 5% density might add only 10 g of support material; at 25% density the same model might add 50 g. Yet the actual surface quality of supported overhangs often does not improve linearly with density — there is frequently a crossover point around 10–15% where you get most of the benefit for a fraction of the material.
This is why pre-slicing estimates are useful even for single-material jobs. If your support estimate is 30% of the model weight, it is worth asking whether the model orientation or geometry can reduce the overhang severity before you commit to the print.
Choosing the right overhang severity category
Gentle. Parts that are mostly self-supporting — a simple bracket, a flat housing — with a few bridging spans or short overhangs. The overhangs are not the main design feature.
Moderate. Typical functional parts with significant unsupported areas: curved bodies, complex shapes, parts with long horizontal spans or protruding features. Most prints in this category.
Severe. Organic models, figurines, highly cantilevered geometry, or parts where support touches most of the underside. Architectural models, character models, and parts with inverted features typically fall here.
Dissolvable versus breakaway supports
The cost calculation differs significantly between support strategies. Dissolvable supports (PVA, HIPS) allow supports in deep internal channels and complex geometries where breakaway would be impossible to remove. The trade-off is cost: dissolvable filaments typically cost more per kilogram than standard PLA. This estimator separates the support material cost so you can price a PVA support spool at its actual cost rather than using the model material’s price per kilogram.
Tips and notes
- This is an estimate. Once sliced, trust the slicer’s exact support figure.
- Tree/organic supports use noticeably less material than grid supports for the same model — treat severe-overhang figures as worst case.
- For dissolvable supports, price the support spool separately; PVA and HIPS often cost more per kg than PLA.
- Lowering support density and raising the support Z-distance reduces both material and removal effort, at some risk to overhang quality.
All calculations run locally in your browser.