Calculate SPI TFT bandwidth, frame transfer time, maximum FPS, required clock for target FPS, and RGB565 framebuffer size for embedded display projects.
Enter resolution, color depth, and SPI settings to estimate bandwidth and frame rate.
Display bandwidth is the amount of pixel data you must transmit per frame. For SPI TFT displays, higher resolution and color depth increase transfer time and reduce practical frame rate.
RGB565 uses 16 bits per pixel, so framebuffer bytes are width × height × 2. Full-frame buffers are often large for small MCUs, especially when double buffering is needed.
Theoretical FPS assumes pixel data transfer only. Actual FPS is lower due to command overhead, driver timing, DMA setup, and software scheduling.
Partial updates can reduce transferred pixels and improve refresh speed. UI elements or region-based redraw strategies often perform better than full-screen updates on SPI displays.
| Resolution | Color depth | Framebuffer size | Notes |
|---|---|---|---|
| 128×160 | RGB565 | 40 KB | Small SPI TFT |
| 240×240 | RGB565 | 112.5 KB | Square TFT display |
| 240×320 | RGB565 | 150 KB | Common ILI9341 display |
| 320×480 | RGB565 | 300 KB | Larger SPI TFT |
| 480×320 | RGB565 | 300 KB | Landscape display |
Typical embedded TFT sizes include 128x160, 240x240, 240x320, and 320x480. Use this calculator to estimate memory and bus performance before final hardware choices.
RGB565 uses 2 bytes per pixel. Multiply width × height × 2 to estimate full framebuffer size in bytes.
Compute bits per frame, divide by effective SPI bitrate to get frame time, then FPS is 1 divided by frame time.
Real systems include command bytes, address windows, software overhead, and bus inefficiencies that reduce practical throughput.
If your UI changes small regions, partial updates often improve responsiveness and reduce SPI bandwidth usage.