Purpose <p>To assess and compare the accuracy of 12 intraocular lens (IOL) power calculation formulas after cataract phacoemulsification surgery in eyes with an axial length (AL) greater than or equal to 26.00&#xa0;mm (≥ 26.00&#xa0;mm).</p> Methods <p>A retrospective case series study including 72 eyes with an AL ≥ 26.00&#xa0;mm that underwent uneventful cataract surgery. Twelve IOL power calculation formulas were evaluated: SRK/T, Holladay 1, Haigis, Holladay 2, Barrett Universal II, Kane, EVO, Pearl-DGS, Hill RBF 3.0, SRK/T and Holladay 1 with the modified W-K AL adjustment, and Holladay 2 with the non-linear W-K AL adjustment. The median absolute error (MedAE), mean absolute error (MAE) and the percentage of eyes within specific prediction error thresholds were calculated and compared across formulas after adjusting the mean error to zero.</p> Results <p>Holladay 1_{modified W-K} obtained the lowest MedAE (0.215 DP), followed by Kane (0.233 DP), Barrett (0.246 DP), Pearl and EVO (0.252 DP). Barrett, Kane and EVO yielded significantly lower MedAEs compared to SRK/T (<i>p</i> &lt; 0.05); and Holladay 1_{modified W-K} yielded significantly lower MedAEs compared to SRK/T_{modified W-K} (<i>p</i> &lt; 0.05). Holladay 1_{modified W-K} achieved the lowest MAE (0.314 DP), followed very closely by Barrett (0.317 DP), and subsequently by Pearl (0.324 DP), Kane (0.329 DP) and EVO (0.331 DP).</p> Conclusion <p>Our study reflects a superior accuracy of the Holladay 1_{modified W-K} formula, along with the Kane, Barrett, EVO and Pearl-DGS formulas in predicting refractive outcomes for eyes with an AL greater than 26.00&#xa0;mm undergoing cataract phacoemulsification surgery.</p>