A gravimetric-amperometric determination of high percentages of calcium is proposed. An exactly weighed amount of EDTA, slightly less than the theoretical amount, is added and the determination is then completed amperometrically. The proposed method is more precise than direct amperometric titration for large amounts of calcium; relative errors in determining 50 mg Ca are: ±1–2% for the proposed method, ±7% for the direct method. A theoretical study of the errors involved confirms the greater precision of the proposed method at the 50-mg Ca level.