Model Building & Hobby

Model building calculators for scale conversion, RC car gearing, model rockets, railroad track planning, and battery sizing.

Matches are ranked by relevance. Use CtrlK anytime to search the full site.

Convert real-world dimensions to model scale dimensions. Supports common model scales like HO (1:87), N (1:160), O (1:48), and more.

Calculate how much paint you need for model kits based on surface area, coats, and whether the surface is primered.

Calculate final drive ratio and theoretical top speed for RC cars based on pinion, spur, diff ratio, and motor specs.

Determine the right motor class for your model rocket based on weight, target altitude, body diameter, and drag.

Calculate wing loading, stall speed, and flying characteristics for RC airplanes based on weight and wing area.

Plan model railroad layouts with minimum curve radius, track spacing, grade limits, and turnout sizing by scale.

Calculate actual and scale speed of slot cars from motor RPM, tire diameter, gear ratio, and scale.

Calculate forced perspective scale transitions for dioramas. Determine foreground and background element sizes for depth illusion.

Calculate thread diameter, rigging lengths, and ratline counts for scale model ship building.

Calculate the right LiPo battery capacity, C rating, and weight for your RC vehicle or aircraft.

Glycerin and water ratio for snow globe viscosity.