When should I use a raft?

Use a raft when printing with warpy materials like ABS or Nylon, when your part has a very small footprint, or when bed adhesion is unreliable. For PLA on a good surface, a brim is usually sufficient.

How many raft layers should I use?

Two to three layers is standard. The base layer provides adhesion, and interface layers create a smooth surface for the part. More layers can help on uneven beds but waste more material.

How do I separate the raft cleanly?

Raft separation depends on the air gap setting in your slicer (typically 0.1-0.2mm). Let the part cool completely, then flex or peel the raft away. A larger air gap makes removal easier but may give a rougher bottom surface.

3DPrintCalcs

Raft Calculator — Extra Material & Time

Estimate extra material and time for raft adhesion layers.

Part Width (X)

Width measurement

Part Depth (Y)

Depth measurement

Raft Margin

Extra area around the part

Raft Layers

Select an option for raft layers

Material Density

Select the material type

How We Calculate This

Formula

Raft dimensions = Part dimensions + 2 x Margin
Base layer volume = Raft area x 0.3mm x 60% infill
Interface volume = Raft area x 0.2mm x 90% density x (layers - 1)
Raft weight = Total volume x Material density

The base layer uses a thicker layer height with gaps for easy removal. Interface layers are denser to create a smooth surface for the part to print on.

Frequently Asked Questions

Related Calculators

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Estimate the contact area and adhesion force for your print footprint.

Brim Width Calculator

Calculate optimal brim width based on part footprint and material shrinkage.

Bed Temperature Calculator

Find recommended bed temperatures for different materials and surfaces.

Last updated: February 2026

All calculations are estimates. Always verify settings with test prints before committing to final prints.