Calculators for IRS procedure
Penalty and interest, statute dates, CDP deadlines, offer amounts, payment plans, BBA imputed underpayments and transcript codes. Every calculator runs in your browser, shows its formula, and cites the Code section, regulation or IRM provision it follows.
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Failure-to-file, failure-to-pay penalty and interest calculator
Figures the late-filing and late-payment penalties month by month, applies the combination rule and the minimum, and adds daily compounded interest at the quarterly rates.
IRS statute date calculator: assessment, collection and refund deadlines
Works out the assessment, collection and refund statute dates from the filing, assessment and payment dates, with the suspensions you enter merged the way the IRM requires.
Late partnership and S corporation return penalty calculator (IRC 6698 and 6699)
Multiplies the per-month amount for the year by the number of partners or shareholders and the months late, with the 12-month cap and the relief to check.
First Time Abate eligibility checker
Walks the IRM's First Time Abate criteria in order and tells you whether the module meets them, fails, or needs the prior years' transcripts.
BBA imputed underpayment estimator
Groups and nets partnership adjustments the way Treas. Reg. 301.6225-1 does, applies the highest rate and credits, and shows the effect of modifications.
IRS transcript code decoder for individual and business accounts
Paste transcript lines and get the IRS's own definition of every transaction code and TC 971 action code, with practitioner notes on the ones that matter.
Offer in compromise reasonable collection potential (RCP) calculator
Builds the minimum doubt-as-to-collectibility offer the way Form 433-A (OIC) does: asset equity at quick-sale value plus 12 or 24 months of remaining income.
Installment agreement eligibility and payment calculator
Tests the balance against the payment plan thresholds the IRS publishes in IRM 5.14.5 and on IRS.gov, and estimates the monthly payment with interest and penalty.
IRS underpayment and overpayment interest rates by quarter
Every quarterly underpayment and overpayment rate since 2017 with its news release or revenue ruling, the IRC 6621 formulas, and a daily compounding calculator.
Collection due process and equivalent hearing deadline calculator
Counts the 30-day CDP window and the one-year equivalent hearing window from a levy notice or lien filing, with weekend and holiday rules and the Tax Court deadline.
IRS account transcript analyzer: dates, statutes, penalties, freezes and First Time Abate
Parses pasted individual or business account transcripts into assessments with their collection statute dates, penalty and interest history, payments, freezes and holds, and screens the three prior years for First Time Abate.
Tax Court petition deadline calculator: notice of deficiency, CDP, innocent spouse and whistleblower
Counts the 90-, 150- or 30-day petition period from the notice date, applies the weekend and District of Columbia holiday rule, honors a later date printed on the notice, and tests a filing or postmark date.
16 letter and checklist templates
FTA and reasonable cause letters, a formal protest, CDP and offer checklists, BBA checklists. Preview each, download as Word.