Introduction: Photoplethysmography (PPG) signals are debated for their potential in blood pressure (BP) measurement. Most current approaches rely on complementary data (e.g., ECG) or require regular calibration with cuff-based devices. This study analyzed the largest dataset to date of paired PPG and cuff BP measurements to assess the feasibility of estimating BP using only PPG signals, without additional inputs or repeated calibration. Methods: Systolic and diastolic BP (SBP, DBP) were recorded using an upper-arm oscillometric cuff, simultaneously with wrist PPG signals from 32,152 European residents (mean age 55.9±11.8 years; 24% female; BMI 27.7±4.6) between March/2021-March/2023 (668,080 paired measure-ments). Six machine learning models were trained using cuff BP as reference (75% training, 15% validation, 15% testing): four baseline models using heart rate (HR), age, morphology (age, gender, BMI), and morphology+HR; and two models based on PPG waveform analysis (PPG alone and PPG+Morphology). Performance was evaluated in the testing set (n=4,823) using Pearson's correlation coefficient (r) to compare estimated versus refer-ence (cuff) BP values, and area under the receiver operating characteristic curve (AUROC), true positive rate (TPR), and true negative rate (TNR) for high BP detection (SBP≥140 or DBP≥90 mmHg), with a ±8 mmHg exclusion zone to account for cuff measurement uncertainty. Results: PPG-based models achieved higher correlation with reference BP (Figure, SBP: r=0.63; DBP: r=0.67) and better high BP detection performance (SBP: AUROC=0.89, TPR=TNR=0.80; DBP: AUROC=0.93, TPR=TNR=0.86), outperforming all baseline models (r<0.35, AUROC<0.68). Conclusion: These findings confirm that PPG signals alone provide suffi-cient information for accurate BP estimation, without relying on complemen-tary data or regular calibration. This supports a pathway toward calibration-free, continual BP monitoring using optical sensors already embedded in wearable and clinical devices – offering the potential to transform hyperten-sion screening and healthcare delivery.