The control of interdialytic weight gain (IDWG) in hemodialysis patients is very important to maintain the quality of dialysis, but this recommendation is not always followed by patients. An increase in IDWG more than normal and unstable has a high risk of length of hospitalization, heart disease, and mortality. Patients need media that can help control their daily IDWG. This study aims to analyze the effectiveness of the IDWG calculator on the stability of IDWG in chronic kidney disease patients undergoing hemodialysis. The research design used a pre-experimental research design with one group pre-post-test. The population of this study amounted to 154 patients undergoing hemodialysis. The sampling technique used was purposive sampling with a sample of 15 respondents. While the research instrument uses the IDWG Calculator Application and the IDWG diary. Data analysis was performed using the Wilcoxon signed-rank test statistic with a significance level of <0.05. The results showed that before using the IDWG Calculator, 4 respondents (26.7%) had a stable IDWG, but after using the IDWG Calculator, 11 respondents (73.3%) had a stable IDWG. The results showed that the value of = 0.020 which means the IDWG Calculator is effective on IDWG stability in patients with chronic kidney disease undergoing hemodialysis in RSUD dr. Harjono Ponorogo. Respondents who underwent using the IDWG Calculator became aware of the daily IDWG status and carried out fluid intake management tips to suit their needs. Patients undergoing hemodialysis should use the IDWG Calculator as an easy and effective medium to control weight gain between two hemodialysis sessions.