All Free Scale Modelling Calculators
Browse all 86 free calculators across 10 categories. Every tool is designed for scale modellers, railway enthusiasts, RC builders and wargamers.
Convert real-world measurements to any model scale and back. Compare scales, calculate speed, weight, area and volume at scale.
Scale Calculator
Convert any measurement between real world and model scale. Supports all common scales.
Real to Scale Converter
Convert a real-world measurement down to your chosen model scale.
Scale to Real Converter
Convert a model measurement back up to find the real-world equivalent.
Scale Ratio Calculator
Find the scale ratio from a real measurement and its model equivalent.
Mixed Scale Calculator
Convert a measurement from one model scale to another without going back to real size.
Scale Speed Calculator
Calculate the correct scale speed so your model moves at a realistic pace.
Scale Weight Calculator
Estimate the scale-equivalent weight of an object using the cube law.
Scale Area Calculator
Convert real-world areas to scale areas and back using the square law.
Scale Volume Calculator
Convert real-world volumes to scale volumes and back using the cube law.
Scale Comparison Calculator
Compare model sizes across different scales side by side.
Mix paints accurately, calculate thinning ratios, airbrush settings, spray coverage and weathering quantities for perfect model finishes.
Paint Mix Calculator
Mix two or more paint colours by ratio to get the exact shade you need.
Thinning Ratio Calculator
Calculate the correct paint-to-thinner ratio for brush, airbrush or spray can.
Airbrush Pressure Calculator
Find the recommended PSI setting for your paint type, nozzle size and technique.
Spray Coverage Calculator
Estimate how much spray paint or primer you need for your model surface area.
Wash Mix Calculator
Calculate the paint-to-medium ratio for panel line washes and pin washes.
Dry Brush Calculator
Work out paint quantity and recommended brush sizes for dry brushing techniques.
Clear Coat Calculator
Calculate how much clear coat (gloss, satin, matt) you need for your model.
Primer Calculator
Estimate primer quantity needed based on model surface area and application method.
Weathering Calculator
Plan weathering product quantities for washes, pigments, oils and streaking effects.
Paint Volume Calculator
Estimate total paint volume needed for a model based on surface area and coat count.
Plan your plastic kit builds with calculators for glue, filler, decals, rigging, photo-etch and build time estimation.
Parts Count Estimator
Estimate total parts count for a kit based on scale, subject type and complexity.
Glue Amount Calculator
Calculate how much plastic cement or CA glue you need for your kit build.
Filler Calculator
Estimate putty or filler needed for seam lines, gaps and corrections.
Decal Calculator
Plan decal application with setting solution and softener quantities.
Rigging Calculator
Calculate rigging line lengths for biplanes, ships and other rigged models.
Photo-Etch Calculator
Estimate CA glue and tools needed for photo-etch detail sets.
Resin Parts Calculator
Plan resin aftermarket part preparation â washing, pinning and glue quantities.
Build Time Estimator
Estimate total build hours based on kit complexity, scale, and detail level.
Essential calculators for model railway layouts â track, curves, gradients, platforms, bridges, signals and baseboards.
Track Length Calculator
Calculate total track length needed for your layout plan including sidings.
Curve Radius Calculator
Find the minimum curve radius for your rolling stock and scale.
Gradient Calculator
Calculate gradient percentages and rise-over-run for inclines and hills.
Point Spacing Calculator
Work out correct spacing between turnouts and crossings for smooth operation.
Platform Length Calculator
Calculate scale platform length based on train lengths and number of coaches.
Bridge Calculator
Size bridges for your layout â span, clearance height and approach grades.
Tunnel Calculator
Calculate tunnel bore dimensions, portal size and minimum length at scale.
Catenary Calculator
Calculate overhead wire heights, mast spacing and wire sag for electrified lines.
Signal Spacing Calculator
Work out realistic signal placement distances for your scale and era.
Baseboard Calculator
Plan baseboard dimensions, support spacing and materials for your layout.
Radio-controlled model calculators for batteries, motors, ESCs, gearing, servos, wing loading, propellers and flight time.
Battery Calculator
Calculate battery capacity, C-rating, discharge rate and run time for your RC model.
Motor KV Calculator
Work out motor RPM from KV rating and battery voltage, or find the right KV.
ESC Rating Calculator
Size your electronic speed controller based on motor current draw and battery setup.
Gear Ratio Calculator
Calculate gear ratios, final drive ratio and top speed for RC cars and trucks.
Servo Torque Calculator
Determine the servo torque needed for your control surfaces or steering.
Wing Loading Calculator
Calculate wing loading to predict flight characteristics and stall speed.
Propeller Calculator
Match propeller diameter and pitch to your motor for optimal thrust.
Flight Time Calculator
Estimate flight or run time from battery capacity and average current draw.
Plan dioramas with calculators for base sizing, terrain, vegetation, water effects, lighting, figure placement and materials.
Base Size Calculator
Calculate the right diorama base dimensions for your subject and scale.
Terrain Calculator
Estimate plaster, foam and scenic materials for terrain features.
Vegetation Calculator
Plan static grass, foliage, tree and ground cover quantities for your scene.
Water Effect Calculator
Calculate resin, water effect and ripple product volumes for water features.
Lighting Calculator
Plan LED quantities, resistor values and power supply for diorama lighting.
Figure Placement Calculator
Calculate realistic spacing and grouping for figures in your diorama scene.
Background Calculator
Size backdrop panels and calculate print dimensions for your diorama.
Material Cost Calculator
Estimate total material costs for your diorama project from base to finish.
Wargaming calculators for army points, paint pots, basing, movement trays, dice odds, range rulers and army costs.
Army Points Calculator
Build army lists to a target points value with unit costs and upgrades.
Paint Pot Calculator
Estimate how many paint pots you need based on army size and colour scheme.
Base Size Calculator
Look up correct base sizes for miniature figures by game system and unit type.
Movement Tray Calculator
Calculate movement tray dimensions for your regiment size and base shape.
Dice Probability Calculator
Calculate hit, wound and save probabilities for your dice rolls.
Range Ruler Calculator
Convert game inches to table distances and check weapon ranges.
Terrain Coverage Calculator
Calculate recommended terrain piece count and coverage for balanced games.
Army Cost Calculator
Estimate the real-world cost to buy and build your full army list.
Calculators for scratch builders â sheet thickness, rod and tube sizing, templates, structural strength, rivets and panel lines.
Sheet Thickness Calculator
Find the correct scale styrene or brass sheet thickness for walls, panels and skins.
Rod Size Calculator
Calculate the right rod diameter at scale for pipes, rails, handrails and aerials.
Tube Size Calculator
Find the correct tube diameter and wall thickness for structural elements at scale.
Template Calculator
Generate dimensions for templates â circles, arches, angles and compound curves.
Structure Calculator
Calculate framing, bracing and panel sizes for scratch-built structures.
Rivet Spacing Calculator
Calculate realistic rivet spacing and row patterns at your model scale.
Panel Line Calculator
Work out panel line widths and spacing for realistic surface detail at scale.
Material Calculator
Estimate quantities of styrene sheet, rod, tube and adhesive for your project.
Find the right tools â drill bit sizes, blade selection, magnification power, lighting setups, cutting mats and compressor settings.
Drill Bit Size Calculator
Find the right drill bit size for pinning, rivet holes and detail work at scale.
Blade Selection Calculator
Choose the right hobby knife blade for cutting, scribing and trimming tasks.
Magnification Calculator
Calculate the magnification power needed for detail work at your scale.
Light Setup Calculator
Plan workbench lighting â lux levels, bulb count, colour temperature and positioning.
Cutting Mat Calculator
Find the right cutting mat size for your workspace and typical project sizes.
Clamp Calculator
Calculate clamp quantity and size needed for sub-assemblies and glue-ups.
Soldering Calculator
Choose the right soldering iron temperature and tip size for model work.
Compressor Calculator
Size an airbrush compressor based on nozzle size, pressure needs and duty cycle.
Planning and budgeting calculators â material costs, build time, collection value, display cases, shipping and competition scoring.
Project Cost Calculator
Estimate total project cost including kit, paints, tools and aftermarket parts.
Build Time Calculator
Estimate total build hours based on complexity, experience and sessions per week.
Collection Value Calculator
Track and estimate the value of your model collection for insurance or sale.
Display Case Calculator
Calculate display case dimensions and shelf spacing for your collection.
Shipping Calculator
Estimate box size, packing materials and weight for shipping models safely.
Competition Score Calculator
Score your model against common IPMS-style competition judging criteria.
Photo Setup Calculator
Calculate backdrop size, camera distance and lighting angles for model photography.
Budget Calculator
Plan your annual hobby budget across kits, paints, tools and events.
Why Use ModelCalcs?
Every calculator on this page is completely free, requires no signup, and works on any device. All tools are built specifically for scale modellers and hobby enthusiasts, using correct formulas for scale conversion, paint mixing, and engineering calculations.
Whether you are converting dimensions between scales, planning a model railway layout, mixing paints for your airbrush, or budgeting a wargaming army, ModelCalcs helps you get accurate results quickly.