Pembelajaran trigonometri di SMK masih terkendala rendahnya kemampuan pemahaman konsep, minat belajar, dan keterbatasan media digital interaktif. Penelitian ini bertujuan mengembangkan media pembelajaran digital “jam sinchan” untuk memfasilitasi pencapaian kemampuan pemahaman konsep trigonometri siswa SMK program keahlian Teknik Mesin di Kabupaten Karawang. Metode yang digunakan adalah penelitian dan pengembangan dengan model ADDIE, melibatkan 20 siswa kelas XI. Instrumen penelitian mencakup lembar validasi ahli media dan materi, angket respon siswa, observasi keterlaksanaan, serta tes uraian pemahaman konsep. Hasil validasi menunjukkan media dinyatakan sangat layak dengan skor 96% dari ahli media dan 92% dari ahli materi. Respon siswa juga sangat positif dengan persentase minat belajar 88,33%, kemudahan pemahaman 90%, dan kemudahan penggunaan 76,67%, sehingga total respon mencapai 84,38%. Dengan demikian, media “jam sinchan” terbukti valid, praktis, dan efktif untuk memfasilitasi pencapaian kemampuan pemahaman konsep trigonometri sekaligus menciptakan pembelajaran yang lebih menyenangkan.Trigonometry learning in vocational high schools (SMK) still encounters challenges such as limited conceptual understanding, low learning interest, and the lack of interactive digital media. This study aims to develop a digital learning medium called “Jam Sinchan” to facilitate students’ attainment of conceptual understanding in trigonometry within the Mechanical Engineering program at a vocational high school in Karawang Regency. The research employed a research and development method using the ADDIE model with a sample of 20 eleventh-grade students. The instruments included validation sheets from media and material experts, student response questionnaires, observation sheets, and a conceptual understanding test. The validation results indicated that the media was categorized as highly feasible, with scores of 96% from media experts and 92% from material experts. Student responses were also highly positive, with percentages of 88.33% for learning interest, 90% for ease of understanding, and 76.67% for ease of use, yielding an overall feasibility score of 84.38%. Thus, “Jam Sinchan” is valid, practical, and effective in supporting students’ conceptual understanding of trigonometry while creating a more engaging learning experience.