Two studies were conducted to evaluate the effect of dietary Ca levels (low, 1% and high, 3%) on ileal endogenous amino acid losses (IEAAL) and standardized ileal amino acid digestibility (SIAAD) in broilers (BR) and laying hens (LH) fed nitrogen-free diets (NFD) and distiller's dried grain with solubles (DDGS)-based diets. A total of 384 male Cobb 500 BR and 288 LH were used in a completely randomized design (CRD) with 16 (BR) or 12 (LH) replicate cages with 6 birds/replicate. IEAAL and apparent ileal digestibility (AID) of AA were analyzed using the GLM procedure of SAS appropriate for a CRD while SIAAD values were analyzed using the GLM procedure of SAS appropriate for a 2 × 2 factorial arrangement of treatments. For BR, IEAAL and N losses (mg/kg of dry matter intake, DMI) were higher (P < 0.05) when NFD with high Ca level was fed (total AA was 39%, N was 35% higher). For most of the AA, AID was higher (P < 0.05) in BR fed DDGS-based diet with high Ca level. High dietary Ca resulted in higher (P < 0.05) SIAAD for all the AA except for Arg, Lys, Met, Cys, and Tyr. For LH, AID of AA was higher (P < 0.05) for the DDGS diet with high Ca level in 13 of the 18 AA evaluated. There was interaction (P < 0.05) between diet Ca level and correction method on LH SIAAD values for Thr, Asp, Gly, and Ser. The SIAAD values for 8 AA were higher (P < 0.05) in birds on high Ca DDGS diet. Correction with low Ca NFD resulted in higher (P < 0.05) SIAAD values for all the AA. Result from this study showed that high Ca increased total IEAAL in BR by 39% but decreased same by 27% in LH. Finally, SIAAD values were increased in BR fed high Ca DDGS-based diet while SIAAD value in LH was lower when correction was done using values from high Ca-NFD fed birds.