The final result on the charged kaon semileptonic form factors from the NA48/2 experiment is presented. The measurement is based on 4.28 million $K^\pm_{e3}$ and 2.91 million $K^\pm_{\mu 3}$ events collected in 2004 with very low background (< 0.1% and ∼ 0.2%, respectively). The joint analysis of these samples provides the most precise combined measurement of $K^\pm_{l3}$ form factors.