Text of IRS Rev. Proc. 2018-27: Adjustment to Annual Limit for HSA Contributions for 2018 (PDF)

"This revenue procedure modifies the annual limitation on deductions for contributions to Health Savings Accounts (HSAs) allowed for individuals with family coverage under a high deductible health plan (HDHP) for calendar year 2018 announced in Revenue Procedure 2018-18 ... For 2018, taxpayers may treat $6,900 as the annual limitation on the deduction for an individual with family coverage under an HDHP pursuant to section 223(b)(2)(B) of the Internal Revenue Code. This revenue procedure makes no other changes to Rev. Proc. 2018-18."
Internal Revenue Service [IRS]

IRS IR 2018-107: Relief for Taxpayers Affected by Reduction of Maximum Deductible Health Savings Account Contribution (PDF)

"A change in the inflation adjustment calculations for 2018 under the Tax Cuts and Jobs Act reduced the maximum deductible HSA contribution for taxpayers with family coverage under an HDHP by $50, to $6,850. Revenue Procedure 2018-27 announces this relief for affected taxpayers and allows the $6,900 limitation to remain in effect for 2018[.]"
Internal Revenue Service [IRS]