https://www.tsp.gov/PlanParticipatio...ionLimits.html

Elective Deferral Limit $19,500 IRC §402(g) Applies to combined total of traditional and Roth contributions. For members of the uniformed services, it includes all traditional and Roth contributions from taxable basic pay, incentive pay, special pay, and bonus pay, but does not apply to traditional contributions made from tax-exempt pay earned in a combat zone.
Annual Addition Limit $57,000 IRC §415(c) An additional limit imposed on the total amount of all contributions made on behalf of an employee in a calendar year. This limit is per employer and includes employee contributions (tax-deferred, after-tax, and tax-exempt), Agency/Service Automatic (1%) Contributions, and Matching Contributions. For 415(c) purposes, working for multiple Federal agencies or services in the same year is considered having one employer.
Catch-up Contribution Limit $6,500 IRC §414(v) The maximum amount of catch-up contributions that can be contributed in a given year by participants age 50 and older. It is separate from the elective deferral and annual addition limit imposed on regular employee contributions.