The present study used multiple calibration indices to capture the complex picture of fifth graders' calibration of feeling of confidence in mathematics. Specifically, the effects of gender, type of mathematical problem, instruction method, and time of measurement (before and after problem solving) on calibration skills were investigated. Fourteen classes (N = 389 fifth graders) were randomly selected from two school mathematics programs, namely the gradual program design and the realistic program design. Students completed two different types of mathematical problems (a set of computation problems and a set of application problems) and reported their feeling of confidence (that they would find the right solution) when first reading the problem statement and again after they had produced the solution of each of the problems. Students' calibration skills were measured using three indices of calibration. Effects on the calibration of feeling of confidence due to gender, instruction method, type of mathematical problem, and time of measurement were found and are discussed.