3D Print Scaling Compensation Calculator
Find the exact scaling factor to apply in your slicer after measuring a calibration print. Accounts for material shrinkage, print temperature, and print speed to correct systematic dimensional errors.
About this calculator
When a printed calibration object measures differently from its modeled size, you need a correction factor to apply before the next print. This calculator computes that factor as: scalingFactor = (targetDimension / measuredDimension) × materialShrinkageFactor × (1 + (temperature − 200) / 5000) × (1 + (60 − printSpeed) / 1000). The base ratio (target ÷ measured) gives you the raw correction. The material shrinkage factor adjusts for the known bulk contraction of the chosen plastic. The temperature correction nudges the factor up or down because higher nozzle temperatures increase flow and slightly expand dimensions, while the speed correction accounts for under-extrusion at high speeds reducing part size. Multiply the result by 100 to get the percentage to enter in your slicer's scaling dialog.
How to use
You modeled a 50 mm cube, printed it, and measured 49.2 mm. Material factor = 1.0 (PLA baseline), temperature = 200 °C, print speed = 60 mm/s. Step 1: base ratio = 50 / 49.2 = 1.01626. Step 2: temperature correction = (200 − 200) / 5000 = 0, so factor = 1.0. Step 3: speed correction = (60 − 60) / 1000 = 0, so factor = 1.0. Step 4: scalingFactor = 1.01626 × 1.0 × 1.0 × 1.0 = 1.01626. Enter 101.63% scaling in your slicer. If you print at 220 °C and 40 mm/s instead, the temperature term adds (220−200)/5000 = 0.004 and speed adds (60−40)/1000 = 0.02, giving 1.01626 × 1.004 × 1.02 ≈ 1.041.
Frequently asked questions
How do I measure a calibration print accurately to use this calculator?
Print a simple calibration object — a 20 mm or 50 mm cube is common — with no scaling applied. Let the part cool fully to room temperature before measuring, because warm plastic can still be slightly expanded. Use digital calipers and take measurements at multiple points along each axis, then average them. Measure X, Y, and Z separately because each axis may have a different error; you may need separate scaling factors per axis if your printer's motion system is not well-calibrated.
Why does print temperature affect the scaling factor in 3D printing?
Nozzle temperature controls melt viscosity and flow rate. At higher temperatures, plastic flows more easily and tends to spread slightly wider, increasing dimensions; at lower temperatures, the filament is more viscous and may under-extrude, reducing dimensions. The correction term (1 + (T − 200) / 5000) in this formula uses 200 °C as a neutral reference point, adding a small positive correction above 200 °C and a small negative one below it. This is a first-order approximation — actual behavior varies by filament brand and hotend design — so empirical calibration prints are always recommended to validate the result.
When should I recalculate my 3D print scaling compensation factor?
You should recalculate any time you change filament brand or material, switch to a different nozzle diameter, significantly change print temperature or speed, or upgrade your printer's motion hardware. Environmental factors like ambient temperature and humidity (especially for hygroscopic materials like Nylon or PETG) can also shift dimensions over time. As a best practice, run a quick calibration cube at the start of any critical batch of parts and compare it to your stored factor before committing to a full print.