What is the dollar amount of HSA contributions allowed each year?

"The maximum amount that may be contributed to an HSA for any year is is a certain amount established by the IRS for each year. The limits are dependent on whether the individual has single coverage or family coverage in their qualified HDHP. Self-only HDHP coverage (individual limit) is a HDHP covering only an eligible individual. Family HDHP coverage (family limit) is an HDHP covering an eligible individual and at least one other individual (whether or not that individual is an eligible individual). The same annual contribution limit applies regardless of whether the contributions are made by an employee, an employer or both.​           

Individuals who are age 55 anytime during the calendar year are eligible for an additional "catch-up" contribution of $1,000.  If enrolled in an HDHP January 1 through December 1 of the current tax year, consumers are allowed to make the full annual maximum HSA contribution for the year. If enrolled in a HDHP for a partial year not including December 1, accountholders are allowed to contribute the prorated amount based on the number of months they were eligible. If enrolled in a HDHP for a partial year including December 1, accountholders are allowed to contribute the full annual maximum for the year. However, in this case if the accountholder does not remain eligible for 12 months after the end of the calendar year in which they enrolled in a HDHP, the accountholders will be subject to income tax and a 10 percent excise tax on HSA contributions for months not covered by a HDHP. Refer the IRS for up to date penalty information.

The total contribution for the year can be made in one or more payments at any time up to tax-filing deadline (without extensions). However, if an individual wishes to have a contribution made between January 1 and April 15 treated as a contribution for the preceding taxable year, they can use the UMB online contribution tool or contribution form and check the box "prior year contribution"?.