The article is devoted to the assessment of direct economic effect of gradual increase of the retirement age in Russia from 2019 to 2028 by 5 years for men and women. The importance of obtaining such a quantitative assessment is substantiated and the methodology is validated. The methodology includes: 1) a three-variant forecast of the working-age population, taking into account the shift in the size of workingage population starting 2019 due to an increase in the retirement age;2) economic and mathematical models based on production functions that allow to reliably assess the impact of the increase in the retirement age on the production of Russian GDP. Based on real statistical data, a three-variant forecast of the workingage population in Russia has been compiled, taking into account the increase in the retirement age. Analysis of the results of three variants of our prognosis showed that the increase in the retirement age not only halted the steady downward trend in the size of working-age population, but also broke the trend, indicating an increase in the size of working-age population in Russia. A study of the constructed economic and mathematical models has shown that raising the retirement age will lead to a slight increase in Russian GDP (by about 0.35% annually). Thus, without significant structural changes in the economy, the direct effect of raising the retirement age in Russia is hardly noticeable in the GDP production.