FERS and CSRS employees and members of the uniformed services may contribute up to the Internal Revenue Code limitation, which is $22,500 for 2023. The contribution for FERS and CSRS for civilian employees may be either a specific dollar amount or a percentage of pay (whole dollars or whole percentages only), while uniformed service members can only elect a percentage of pay; any amounts will be adjusted once the annual IRC limitation is reached. Once the contribution amount is selected, it automatically renews each year at the same amount or percentage until the participant elects otherwise. In addition, participants age 50 or older may also make "catch-up" contributions up to the IRC limitation, which is $7,500 for 2023. The catch-up contributions are tax-deferred and allow age eligible participants to defer up to $30,000 for 2023 in their TSP account. Civilian employees may only contribute from regular pay (the standard pay for their grade plus applicable locality pay); they cannot contribute from bonuses or any overtime. Uniformed service members are permitted to make contributions from both basic pay as well as from incentive, special, or bonus pay, but are subject to the regular contribution limits. Members of the uniformed services who deploy to designated combat zones are subject to the combat zone tax exclusion, which allows tax-exempt income earned. Contributions to the TSP by uniformed service members in a combat zone are contributed to the TSP as tax-exempt, and accrue tax-deferred earnings. Tax-exempt contributions are not subject to the IRC elective deferral limit. Participants who are both civilian federal employees and members of the uniformed services will have two separate TSP accounts if they elect to contribute while in civilian and/or uniformed service status; however, the total tax-deferred contributions in both may not exceed the IRC elective deferral or catch-up limits. In addition, the total tax-deferred, tax-exempt, and agency contributions made to both TSP accounts are subject to the IRC Section 415(c) overall limitation, which is $58,000 for 2021. Catch-up contributions made are in addition to the elective deferral and 415(c) limits. Participants may also roll over existing 401(k) or Individual Retirement Accounts (traditional IRAs only) into the TSP. Matching contributions All FERS employees automatically have 1% of base pay contributed by their agency, even if the employee does not participate in TSP; the employee cannot waive this requirement. Additional matching contributions are made dollar-per-dollar up to 3% of base pay