1% Low & 0.1% Low FPS Calculator

How to use it

Paste a list of frame times in milliseconds, one per line or separated by commas. If you have FPS readings instead, switch "Plain numbers are" to FPS values. You can also paste or load a CSV exported from a capture tool. The analyzer looks for a frame-time column such as MsBetweenPresents (PresentMon and CapFrameX exports) or a column named Frametime, which you can produce from an MSI Afterburner log in a spreadsheet. Press Analyze. Nothing is uploaded.

How the numbers are calculated

Average FPS is total frames divided by total time, not the average of per-frame FPS, which would overstate it. 1% low is the average FPS of the slowest 1% of frames: we sort frames by frame time, take the slowest 1% (at least one frame), and divide their count by their combined time. 0.1% low does the same with the slowest 0.1%. Some tools report percentile values instead, the FPS at the 99th or 99.9th percentile frame time, so we show those as well. Expect small differences from other software that uses the other method. A stutter here is any frame that takes more than twice the median frame time.

Frame times are the other side of FPS. Use our FPS to frame time converter to translate between them.

FAQ

Why do 1% lows matter? Average FPS hides hitches. Two systems can both average 100 FPS while one has frequent 40 ms spikes. The lows reflect how smooth a game actually feels.

How long should my capture be? At least 60 seconds of consistent gameplay. 0.1% lows from short captures rest on only a handful of frames and swing a lot between runs.

Why doesn't my CSV load? Make sure it has a header row with a frame-time column, or paste just the numbers. Afterburner's native .hml format isn't parsed directly. Export the frame-time column first.

Is my log sent anywhere? No. Parsing, math, and the chart all run locally in your browser.