Texture Memory Calculator

Estimate texture memory before it becomes a performance problem

A texture budget starts with the surfaces the player can actually see. Compare resolution and storage formats before importing a full material library, then confirm your choices with the engine profiler. This calculator helps estimate texture storage; it does not compress images or measure your graphics card.

For an asset with base color, normal and roughness maps, calculate each format group separately and add the totals. The texture count applies the same dimensions and format to every texture. Use the PBR map setup guide to identify the channels your material actually uses before counting them.

How texture memory is calculated

For each mip level, RGB8 uses width × height × 3 bytes and RGBA8 uses width × height × 4. BC formats store 4 × 4 texel blocks: multiply ceil(width / 4) × ceil(height / 4) by 8 bytes for BC1 or 16 bytes for BC3, BC5 and BC7. Even a 1 × 1 compressed mip needs a complete block.

Each enabled level is summed before multiplying by the texture count. This is a tightly packed storage estimate: dimensions that are not multiples of four are rounded up to full blocks for this calculation, not certified as valid texture resources on every graphics API. Imported size and alignment rules can differ.

How much memory do mipmaps use?

A full chain halves each dimension, rounding down and never going below one, until both reach 1 × 1. For a large square, power-of-two uncompressed texture, the extra levels approach one third of the base size. That shortcut is less useful for small textures, narrow rectangles and block-rounded levels, so this tool adds the real level sizes instead.

For example, 2048 × 2048 RGBA8 occupies 16 MiB without mips and 22,369,620 bytes (about 21.33 MiB) with all 12 levels. A 1 × 8 RGBA8 texture has levels 1 × 8, 1 × 4, 1 × 2 and 1 × 1: 60 bytes in total instead of a simple 33% allowance. Mipmaps can improve sampling at a distance; disabling them solely to save storage may introduce visible aliasing.

BC1 vs BC3 vs BC5 vs BC7

BC1 favors compact color storage with limited alpha. BC3 provides a separate alpha component. BC5 stores two channels and is often chosen for normal-map data. BC7 targets higher-quality color and alpha on platforms that support it. These choices are not interchangeable simply because several occupy the same space: inspect your imported texture and target platform.

See Microsoft's BC format reference for storage and support details. Before optimizing a normal map, resolve shading problems with the normal-map convention troubleshooting guide; changing compression will not repair an inverted green channel.

Why texture resolution matters

A 4096 × 4096 texture contains four times as many pixels as a 2048 × 2048 texture. With the same uncompressed format, its base memory also quadruples. Decide whether that detail is visible using the texture resolution guide for 3D assets, and keep detail consistent across objects with the texel-density workflow.

Reducing texture memory addresses one part of an asset budget. Geometry, draw calls and materials also matter: use the game asset optimization workflow to identify the bottleneck before changing every texture.

Texture memory is only an estimate

The result estimates theoretical storage for the selected 2D texture levels, not exact VRAM used by Unity, Unreal Engine or another runtime. GPU, platform, graphics API, allocation alignment, padding, import settings and format conversion can change the footprint. RGB8 is particularly important: Unity documents RGB24 conversion to RGBA32 on GPUs without native support. Choose RGBA8 here to estimate that expanded storage.

Streaming may keep only some mips resident. Virtual texturing, arrays, cubemaps, runtime or CPU copies, render targets and engine implementation add other considerations outside this model. The number shown is also different from a PNG or JPEG file's compressed disk size. Check the imported format and resident memory on the actual target device.

Use the Unity import-settings checks when the engine result differs from the estimate. Return to 3DSkillUp Tools for other focused texture utilities.