How much border should I leave around my subject?

A good rule of thumb is 30-50% extra on each side for vehicles, more for figure scenes where you want context. Vignettes can be tighter with 15-20% border. The calculator adjusts based on your subject type.

What base materials are best for dioramas?

MDF and plywood (3-6mm thick) are the most popular choices. MDF is flat and easy to cut but can warp if sealed badly. Plywood is stronger but heavier. Picture frames, wooden plaques and commercial diorama bases also work well.

Should the base be rectangular or can I use other shapes?

Rectangular and square bases are the most common and easiest to frame. Oval and circular bases work well for vignettes. Irregular shapes can add visual interest but are harder to display and transport.

Do I enter the model dimensions or the real-world dimensions?

Enter the model dimensions in millimetres. Measure your built model (or check the kit box for approximate finished dimensions). The calculator works from the model size to determine the base needed.

ModelCalcs

Base Size Calculator — Diorama Base Dimensions

Calculate the right diorama base dimensions for your subject and scale. Accounts for border space and scene composition.

Subject Type

Model Length

Length of your built model

Model Width

Width of your built model

Scale

Add scenic border

Extra space around subject for terrain and scene

How We Calculate This

The calculator takes your model dimensions and applies a border multiplier based on the subject type.

Formula

Base dimension = Model dimension x Border multiplier
Vehicle scenes use 1.5x, figure groups use 1.8x, vignettes use 1.3x

These multipliers come from compositional guidelines used by competition diorama builders. The border gives breathing room and prevents the subject feeling cramped.

Frequently Asked Questions

Related Calculators

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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.

Last updated: February 2026

All calculations are estimates. Always verify quantities before purchasing materials.