Dalam gerakan harmonik mudah, terdapat dua jenis tenaga iaitu tenaga kinetik dan tenaga keupayaan kenyal. Maka jumlah tenaga ialah

E = 1 2 m v x 2 + 1 2 k x 2 {\displaystyle E={\frac {1}{2}}mv_{x}^{2}+{\frac {1}{2}}kx^{2}\,} E = 1 2 m [ − ω A s i n ( ω t + ϕ ) ] 2 + 1 2 k [ A c o s ( ω t + ϕ ) ] 2 {\displaystyle E={\frac {1}{2}}m[-\omega Asin(\omega t+\phi )]^{2}+{\frac {1}{2}}k[Acos(\omega t+\phi )]^{2}\,} E = 1 2 k A 2 s i n 2 ( ω t + ϕ ) + 1 2 k A 2 c o s 2 ( ω t + ϕ ) {\displaystyle E={\frac {1}{2}}kA^{2}sin^{2}(\omega t+\phi )+{\frac {1}{2}}kA^{2}cos^{2}(\omega t+\phi )\,} E = 1 2 k A 2 {\displaystyle E={\frac {1}{2}}kA^{2}\,}