Basic knowledge of mathematics is essential for solving problems contextually. Mathematics has a function for the development of the ability to calculate, measure, find, and use mathematical formulas that can provide students with an understanding of concepts related to life phenomena. One ability that is synonymous with understanding problems contextually is numeracy ability. Numeration has a main focus, namely the ability of students to formulate, apply, and be able to interpret mathematics in various contexts that include mathematical reasoning and using mathematical concepts, methods, facts, and auxiliary media, explaining, and predicting phenomena in everyday life. This study aims to determine the construct of numeracy ability test instruments for class VIII public junior high school students in Pekalongan Regency, determine the quality of numeracy ability test instruments for class VIII public junior high school students in Pekalongan Regency, and determine the numeracy ability profile of class VIII public junior high school students in Pekalongan Regency. This research method approaches quantitatively by developing instruments using CFA and IRT mixed models. This research was conducted at the junior high school level within the scope of the education office of Pekalongan Regency, Central Java Province, by taking 6 schools as samples. Content validity using Aiken V and Cronbach Alpha reliability as well as item characteristics with mixed IRT and descriptive analysis. The results of this study, namely (1) Construction of numeracy ability instruments for grade VIII State Junior High School students, which are related to the content of algebra, numbers, geometry, and measurement, as well as data and uncertainty. In addition, using personal, socio-cultural, and scientific contexts, using cognitive levels of understanding, application, and reasoning, (2) The quality of numeracy ability instruments is declared valid and reliable, and in construct validity all items are fit as seen from the Loading Factor Standardized Solution value of more than 0.3 and p-value < 0.05 and the reliability of the high category and the estimated characteristics of the items show that the question items are included in the category both in terms of difficulty, and (3) The numeracy ability of junior high school students in Pekalongan Regency shows that there are 36 students out of 599 students classified as proficient with a percentage of 6%, 139 students out of 599 students classified as proficient with a percentage of 23%, 390 students out of 599 students classified as basic with a percentage of 65%, and 34 students out of 599 students classified as needing special intervention with a percentage of 6%.