Eighth Mile to Quarter Mile
Calculator
Scale an eighth-mile elapsed time using a user-selected conversion factor. The default 1.57 factor is a heuristic, not a validated prediction for every vehicle.
Your setup
Your results
CalculatedThe factor expresses an assumption about the second half of the run.
No universal factor exists. This is user-controlled extrapolation; it is unsuitable as a guaranteed dial-in.
How the calculation works
Follow the formula and keep the input units consistent at every step.
estimated quarter-mile ET = eighth-mile ET × selected factor- Read the measured eighth-mile ET.
- Choose a factor supported by your own comparable runs.
- Multiply to get a provisional quarter-mile ET.
A Worked Example
8.00 s × 1.57 = 12.56 s. Changing the factor to 1.60 gives 12.80 s, a 0.24 s difference.
What Your Result Means
The factor expresses an assumption about the second half of the run.
Assumptions & Limitations
No universal factor exists. This is user-controlled extrapolation; it is unsuitable as a guaranteed dial-in.
Common Mistakes
Do not double the eighth-mile ET or confuse distance scaling with time scaling.
Questions about this calculation
Which values should I enter?
Read the measured eighth-mile ET. Do not double the eighth-mile ET or confuse distance scaling with time scaling.
How should I interpret the result’s precision?
Displayed results are rounded for readability. Intermediate calculations retain floating-point precision; extra displayed decimals do not improve your input accuracy.
Can I use metric units?
Yes. Select Metric above the calculator to convert your inputs. Results always state their units. Tire-size designations keep their conventional mm and inch units.
What are the main limitations?
No universal factor exists. This is user-controlled extrapolation; it is unsuitable as a guaranteed dial-in.
Method, sources & relevant guides
Hale coefficient model: ET constant 5.825 and speed constant 234. Lucius documents the formulas and compares them with road-test data. These are empirical relationships, not physical laws or calibrated vehicle predictions.
Jeff Lucius / Stealth 316 — Quarter-mile formulas and original regression analysisMethod documentation updated October 18, 2026. Independent professional review has not been claimed. Read the calculation and review policy.