Scale Factor Calculator was built for people who repeatedly need the same small piece of maths: take an object's length, width and height, multiply them by a scale factor, and find out how much surface the result has. Model makers, 3D printing hobbyists, product designers, packaging planners, students and teachers all run into it.
What the tool does
- Scales length, width and height uniformly using either a magnification multiplier or a percentage.
- Calculates total surface area for three reference models: a rectangular box, an ellipsoid (sphere) and a rectangular-base pyramid.
- Draws the original and scaled models side by side so the difference is visible, not just numeric.
- Copies results to the clipboard or exports them as a text file.
The formulas used
- Box: 2 × (LW + LH + WH).
- Sphere / ellipsoid: the Knud Thomsen approximation, accurate to roughly 1% for typical proportions.
- Rectangular-base pyramid: base area plus four triangular faces derived from their slant heights.
Accuracy and limits
Results are mathematical idealisations. Real objects have fillets, chamfers, wall thickness, tolerances and material shrinkage that this tool does not model. Treat the output as a planning estimate and confirm critical dimensions against your CAD data or a physical measurement before committing to production.
Privacy by design
Every calculation runs locally in your browser. Dimensions you type are never transmitted to or stored on a server. You can read more in the privacy policy.
Feedback
Suggestions, corrections and feature requests are welcome through the contact page.