Post-disaster aid distribution remains vulnerable to subjective beneficiary selection, inconsistent assessment standards, fragmented records, and limited decision traceability. This study developed a web-based Decision Support System (DSS) using Simple Additive Weighting (SAW) to support standardized and documented prioritization of post-disaster aid recipients. Six criteria housing damage, household socioeconomic condition, vulnerable household members, female-headed household status, self-recovery capacity, and access to basic necessities were derived from interviews with BPBD personnel, field observations, and reviews of relevant regulations and administrative documents. The system was developed through a modified Waterfall process using PHP 8, CodeIgniter 4, and MySQL. Its novelty lies not in proposing a new decision-making method, but in implementing SAW as a governed and traceable administrative workflow that integrates configurable criteria, administrator-adjustable weights, beneficiary-data verification, role-based access, automated reporting, and audit logging. Functional conformity was examined through nine black-box testing scenarios. Computational consistency was assessed in one manual verification scenario involving three alternatives by comparing system-generated and independently calculated normalization results, preference scores, and rankings. All nine functions produced the expected outputs, while the three-alternative case reproduced the manual preference scores and ranking order to four decimal places. These findings demonstrate functional conformity and calculation reproducibility only within the limited evaluation scope. Field targeting accuracy, ranking stability, distributive fairness, security, usability, and institutional effectiveness were not evaluated and require validation using larger datasets, realistic disaster scenarios, and operational deployment