Enter Custom Resolution Values
Formula Used
Total horizontal pixels = active width + horizontal blanking
Total vertical lines = active height + vertical blanking
Pixel clock = total horizontal × total vertical × refresh rate
Visible bandwidth = width × height × refresh × effective bits per pixel
Timed link estimate = total pixels × refresh × effective bits per pixel × overhead factor
PPI = √(width² + height²) ÷ screen diagonal
Dot pitch = 25.4 ÷ PPI
The calculator reduces the resolution ratio with the greatest common divisor. It estimates color load from bits per channel and chroma format. The result is a planning estimate, not a driver override.
How to Use This Calculator
- Enter the active width and active height of the custom mode.
- Enter the refresh rate you want to test.
- Select a timing profile. Use manual blanking when you know exact values.
- Add color depth, color format, and screen diagonal.
- Enter target scaling values if the mode will be scaled.
- Set your planning pixel clock and link bandwidth limits.
- Press the calculate button. Review clock load, bandwidth, PPI, and notes.
Example Data Table
| Mode | Refresh | Blanking style | Color | Typical use |
|---|---|---|---|---|
| 1920 × 1080 | 144 Hz | Reduced | 8 bpc RGB | High refresh gaming test |
| 2560 × 1440 | 120 Hz | Conservative | 10 bpc 4:4:4 | Sharp desktop planning |
| 3840 × 2160 | 60 Hz | Reduced | 8 bpc RGB | UHD monitor check |
| 3440 × 1440 | 100 Hz | Tight | 8 bpc RGB | Ultrawide mode test |
Understanding Custom Display Timing
Signal Timing Basics
Custom resolutions look simple because they start with width and height. The physics behind them is broader. A display must draw every pixel, move through blanking intervals, and repeat the scan at the selected refresh rate. Each choice changes the pixel clock. That clock tells the graphics card and monitor how fast the signal must travel.
This calculator treats a video mode as a timed stream. Active pixels form the visible image. Horizontal and vertical blanking add hidden pixels and lines. They give the monitor time to reset the scan. Modern panels often use reduced blanking, but very tight values can fail on older scalers, cables, or adapters.
Bandwidth And Density
Bandwidth is the next limit. A sharper image or faster refresh rate raises the number of bits sent each second. Color depth also matters. Ten bit color needs more data than eight bit color. Chroma formats reduce color detail to save bandwidth. This is why one mode may work in 4:2:0 but fail in full RGB.
Pixel density gives another useful check. It links resolution with screen size. A high PPI value can make text crisp, but it can also make interface items small. Dot pitch shows the same idea in millimeters. Smaller pitch means pixels sit closer together.
Scaling And Hardware Limits
Scaling should be checked before applying a custom mode. A non integer scale can soften text. Unequal horizontal and vertical scaling can stretch shapes. The calculator compares a source mode with a target size, so you can see whether the scale is even.
Pixel clock limits are practical, not just theoretical. Monitor firmware, cable quality, ports, adapters, and drivers can stop a mode even when basic math looks acceptable. A safe result should still be tested carefully. Start near a known working mode. Increase one value at a time. Keep the refresh rate modest when exploring high pixel counts.
Practical Planning
Use this tool as a planning aid before changing display settings. It does not rewrite monitor data. It estimates the load created by a proposed mode. The values help you decide whether the mode is sensible, efficient, and close to your hardware limits.
For gaming, response feel often improves with refresh rate. For design work, density and color depth may matter more. For old displays, conservative blanking can be safer. For modern panels, reduced blanking can lower pixel clock and leave more bandwidth headroom. A balanced custom resolution respects all these limits together.
Another useful value is line rate. It shows how many scan lines move each second. High line rate can stress signal processors. Frame time also matters. A lower frame time means each image is replaced sooner. This improves motion clarity when the panel can keep up. When the panel cannot keep up, skipped frames, blank screens, or unstable colors can appear. These symptoms mean the mode should be reduced or the timing should be made more conservative. Always document working settings.
FAQs
What does this calculator estimate?
It estimates display timing, pixel clock, active pixels, bandwidth, PPI, dot pitch, frame time, line rate, scaling, and headroom against user-selected limits.
Does this tool change my monitor settings?
No. It only performs calculations. You must use your display driver or a separate utility to apply a custom mode.
What is pixel clock?
Pixel clock is the rate at which total timed pixels are sent. It includes visible pixels and blanking intervals, so it can be higher than the visible image load.
Why does blanking matter?
Blanking adds hidden timing space between active lines and frames. It affects pixel clock and signal demand, even though it is not visible on the screen.
Which timing profile should I choose?
Use reduced blanking for modern panels. Use conservative or legacy estimates when testing older displays, adapters, or unknown hardware. Use manual values when exact timing is known.
Why does color depth increase bandwidth?
Higher color depth sends more bits for each pixel. Ten bit color sends more data than eight bit color, which raises link demand.
What does chroma subsampling do?
Chroma subsampling reduces color detail to lower data rate. It can help high resolutions work, but text and fine colored edges may look less sharp.
What is a safe headroom value?
Staying below about ninety percent of your selected clock and link limits gives useful room for overhead, cable loss, adapter limits, and monitor tolerance.
Can a mode fail even when math looks good?
Yes. Firmware, ports, cables, adapters, drivers, and scaler behavior can reject a mode. Always test changes carefully and keep a known working mode available.
Why compare target width and height?
The comparison shows scaling behavior. Equal scale factors preserve shape. Unequal scale factors can stretch circles, text, and interface elements.
What does PPI tell me?
PPI shows pixel density for the selected diagonal size. Higher PPI can improve sharpness, but it may require display scaling for comfortable reading.