The interest rates on overpayments and underpayments are increased slightly for the first quarter of 2019, as compared with the rates for the prior quarter (Rev Rul. 2018-32). The rates are:
The 6% rate is used to figure estimated tax penalties for individuals for the first quarter of 2019 and also the first 15 days of April.
As the Federal Reserve continues to gradually raise rates, it is expected that future IRS interest rates will also increase.
Generally, an unmarried person who maintains a household for dependents and is allowed to compute his or her tax based on head of household rates, which are more favorable than single person rates.