Accurately compare powerlifting performances across different bodyweight classes. Enter your bodyweight (kg), total lifted (kg) and gender to compute your Wilks score — the official coefficient used by IPF from 1998–2019. Includes interactive Wilks coefficient curve and real-time scoring.
The Wilks Coefficient (or Wilks Formula) is a mathematical method developed by Robert Wilks, former president of the Australian Powerlifting Union, to allow fair comparison of lifters across different bodyweight categories. It is the official coefficient used by the International Powerlifting Federation (IPF) from 1998 until 2019, when it was replaced by the IPF GL Points system. Nevertheless, Wilks remains the most recognized standard in powerlifting history and is widely used in amateur and retro competitions, online rankings, and personal tracking.
? Formula for Wilks Coefficient λ (Male):
λ = 500 / (a + b·w + c·w² + d·w³ + e·w⁴ + f·w⁵)
with coefficients: a=-216.0475144, b=16.2606339, c=-0.002388645, d=-0.00113732, e=7.01863E-06, f=-1.291E-08
Wilks Score = Total Lifted (kg) × λ
For females, a different set of coefficients is used (see code references, derived by Robert Wilks from statistical analysis of world-class powerlifters).
The coefficients were derived by analyzing the relationship between body mass and world‑record totals in powerlifting. The polynomial of degree 5 was chosen to provide a smooth, continuous fit. The value 500 in the numerator is a scaling factor so that the coefficient for a 75 kg male is approximately 1.0. The curve peaks for men around 75–80 kg, meaning lifters in those classes have a multiplier close to 1, while lighter lifters receive a coefficient >1 (advantage) and heavier lifters receive λ <1 (disadvantage). For women, the peak occurs around 60–65 kg.
Robert Wilks published the formula in the late 1990s after analyzing data from thousands of elite lifters. It revolutionized powerlifting by creating a standardized, objective measurement that allowed federations to compare athletes regardless of weight class. In 2019, the IPF transitioned to GL (Gepulido‑Lombardo) Points, which addresses some mathematical limitations of Wilks (e.g., extrapolation at extreme bodyweights). However, Wilks remains the gold standard for legacy meets and casual comparison.
| Gender | Bodyweight (kg) | Total (kg) | Wilks Coefficient | Wilks Score | Strength Level |
|---|---|---|---|---|---|
| Male | 66.0 | 550 | 0.8472 | 466.0 | Elite |
| Male | 83.0 | 720 | 0.9352 | 673.3 | World Class |
| Male | 105.0 | 780 | 0.9758 | 761.1 | Elite |
| Female | 52.0 | 350 | 1.1782 | 412.4 | Advanced |
| Female | 63.0 | 450 | 1.0667 | 480.0 | Elite |
| Female | 84.0 | 500 | 0.8901 | 445.1 | Competitive |
Lifter A: Male, 73 kg bodyweight, 620 kg total → Wilks Score = 620 × 0.9579 = 593.9.
Lifter B: Male, 93 kg bodyweight, 680 kg total → Wilks Score = 680 × 0.9352 = 635.9.
Despite Lifter B having a heavier total, their Wilks score (635.9) is higher than Lifter A (593.9), meaning Lifter B achieved a relatively stronger performance considering bodyweight. This allows fair ranking in a competition with mixed weight classes.