An electrocardiogram (ECG)can identify any cardiac activity abnormalities. The electrical signal produced when the heart muscles contract and relax, or the ECG, is contaminated with power line and instrument noise during recording. Wavelet algorithms can be used to denoise the ECG signal. For a successful denoised ECG, it is crucial to adjust the wavelet decomposition level. In this study, wavelet transformation technique is used to simulate noisy synthetic ECGs and denoise them. At each stage of decomposition, the Mean Square Error (MSE) between the clean synthetic ECG and denoised synthetic ECG is computed. According to the examination of MSEs, the level of wavelet decomposition can be optimized to produce an efficient denoised ECG output.