How the formula works

Terms

• E is your estimated model runtime memory, in decimal GB.
• K is any additional context or cache reserve. A blank field is treated as an assumed 0 GB.
• R is your OS and application reserve.
• p is your uncertainty input in percent. For example, entering 20 means 20%; it is not a statistical confidence interval.
• M is optional installed unified memory. Leave it blank to see the range without headroom comparison.

Arithmetic

Base = E + K + R
Low = Base × (1 − p / 100)
High = Base × (1 + p / 100)
Upper headroom = M − High
Base headroom = M − Base

If the uncertainty input is 20, the normalized fraction is u = p / 100 = 0.20. The low and high values are Base × (1 − u) and Base × (1 + u).

Rounding and signs

Displayed numbers use at most two decimal places. Headroom sign and status come from the rounded display value, and negative zero is normalized. A small positive or negative remainder that rounds to zero is shown as “No headroom at displayed precision.” The underlying arithmetic retains its full JavaScript number precision.