The IRS announced the release of a new calculator to determine interest rates for large, multi-year construction and manufacturing projects. The calculator is named Percentage-of-Completion Method (PCM) Look-Back Interest Calculator and is MS Excel based. It supports calculations for Form 8697, Interest Computation Under the Look-Back Method for Completed Long-Term Contracts. However, it does not address all fact patterns or complexities associated with look-back interest calculations.
“The IRS is focused on improving and enhancing how we serve taxpayers,” said IRS Chief Executive Officer Frank J. Bisignano. “We are transforming the IRS into a digital-first agency that provides the best possible experience for taxpayers, and tools like this calculator are an important step in that effort,” he added.
The look-back interest is determined using a three-step process:
- Hypothetically reallocating income to prior tax year based on actual revenues and costs;
- Computing hypothetical tax overpayments or underpayments of tax; and
- Calculating interest on tax underpayments or overpayments.
Taxpayers and tax practitioners may submit feedback about the calculator, by emailing Stakeholder Liaison and including “Look-Back Interest Workbook Feedback” in the subject line. More information can be found here.
IR 2026-70
