Free STL Viewer
Open an STL locally in your browser, inspect it in 3D and see its dimensions and triangle count.
Open STL Viewer3D printing file tools
3D Quality Tools
Free tools to check, measure and prepare 3D printing files.
Choose a tool
Currently supporting STL and 3MF files.
STL tools
STL Quality Checker
Find common mesh problems before printing, including open edges, non-manifold geometry, duplicate triangles and orientation issues.
Check STL qualitySTL Print Preflight Checker
Run mesh, size, printer-fit, sampled wall-thickness and volume checks together before slicing.
Run STL preflightSTL Repair Tool
Clean duplicate and degenerate triangles, and correct simple orientation issues before checking the STL again.
Clean an STL safelySTL Watertight Checker
Check whether an STL has a closed surface, open edges or possible holes.
Check watertightnessSTL Manifold Checker
Check whether an STL is closed and manifold, with clear counts for open edges, non-manifold edges and separate shells.
Check STL topologySTL Dimensions Checker
Measure an STL, convert units, calculate proportional scaling and check whether it fits your printer.
Measure an STL fileSTL Scale Tool
Resize an STL proportionally by percentage, target dimension, or an assumed unit conversion, then download it locally.
Scale an STLSTL Wall Thickness Checker
Estimate sampled wall thickness locally and identify areas that may need closer print-preparation review.
Check wall thicknessSTL Overhang Checker
Highlight downward-facing geometry that exceeds your chosen overhang review threshold.
Check overhang riskSTL Splitter
Split a valid STL into two capped printable parts.
Split an STLSTL Volume Calculator
Calculate your model’s volume, convert units and estimate approximate material weight.
Calculate STL volumeSTL Triangle Counter
Count triangles and understand mesh complexity before slicing or sharing.
Count STL trianglesSTL File Size Reducer
Convert ASCII STL to binary locally or simplify a copy with clear before-and-after file and triangle counts.
Reduce STL file sizeSTL to 3MF Converter
Convert an STL into a basic 3MF locally and choose the unit for its existing coordinates.
Convert STL to 3MF3MF tools
Free 3MF Viewer
Open a 3MF model locally, inspect it in 3D and review its declared units, dimensions and triangle count.
Open a 3MF file3MF Quality Checker
Check 3MF mesh quality, declared units and build-item geometry before slicing.
Check 3MF quality3MF Print Preflight Checker
Resolve a 3MF build locally and check unit, size, printer fit, mesh integrity, sampled wall thickness and volume guidance together.
Run 3MF preflight3MF Repair Tool
Safely remove duplicate and degenerate triangles from a 3MF package without rebuilding its resources.
Repair a 3MF file3MF Watertight Checker
Check resolved 3MF build geometry for open edges before slicing.
Check 3MF watertightness3MF Manifold Checker
Check resolved 3MF geometry for open edges, non-manifold edges and separate shells.
Check 3MF topology3MF Dimensions Checker
Measure final 3MF build dimensions, confirm declared units and check printer fit.
Measure a 3MF file3MF Volume Calculator
Calculate resolved 3MF build volume and estimate solid-model material weight.
Calculate 3MF volume3MF Wall Thickness Checker
Estimate sampled wall thickness in resolved 3MF build geometry locally, including transforms and repeated objects.
Check wall thickness3MF Overhang Checker
Review resolved 3MF build geometry for downward-facing overhang risk before slicing.
Check overhang risk3MF Triangle Counter
Count triangles in the resolved 3MF print build before slicing.
Count 3MF triangles3MF to STL Converter
Export resolved 3MF build geometry as one binary STL locally in your browser.
Convert 3MF to STLPlanning and functional tools
3D Printer Fit Checker
Check an STL or 3MF bounding box against a named printer or custom build volume, with local unit, clearance, rotation and scale guidance.
Check printer fit3D Print Orientation Planner
Compare six sensible STL or 3MF build directions for printer fit, downward-facing geometry and estimated bed contact.
Plan an orientation3D Print Bed Layout Planner
Arrange multiple STL and 3MF model footprints on your saved printer bed before opening the slicer.
Plan a print bed3D Print Tolerance & Clearance Calculator
Turn a chosen fit intent and your calibration measurements into editable hole and pin model dimensions.
Calculate a fit3D Print Shrinkage Calculator
Calculate per-axis CAD or slicer scale compensation from your own measured calibration print.
Calculate shrinkage3D Print Cost Calculator
Estimate filament, energy, machine and labour costs from slicer values or model volume.
Calculate print cost3D Printing Price Calculator
Build a customer quote from production costs, quantity and target profit margin.
Calculate a priceFilament Length Calculator
Convert filament weight to length, or length to weight, using spool diameter and material density.
Convert filament lengthG-code and print workflow
G-code Viewer & Preflight Checker
Open sliced G-code locally to inspect parsed layers, extrusion and travel paths, metadata and preflight details before printing.
Inspect G-codeCollections and next-job planning
Batch STL and 3MF Checker
Check a small collection locally and export independent findings, settings and sampled-check limits.
Check a collectionSTL Revision Comparison
Overlay before/after exports in one coordinate frame and inspect bidirectional sampled surface distances.
Compare revisionsFilament Remaining Calculator
Subtract empty-spool tare and reserve, then check a complete sliced job or number of copies.
Check spool sufficiencyNozzle, Layer Height and Wall Planner
Separate diameter from actual line width and estimate nominal wall lines before slicer review.
Plan wall linesVolumetric Flow Calculator
Calculate requested throughput without inventing a hotend limit or recommended machine speed.
Plan requested flowPrint Finish Time Calculator
Add elapsed slicer duration to a chosen start across dates and daylight-saving boundaries.
Plan a finish time