Until you know who made each product, your material assistance cost ratio is a range, not a number. Enter your costs and what you know about each supplier to see the range, the minimum it has to clear, and which unknowns decide the answer.
Enter at least one cost to see your range.
Arithmetic on the figures you enter, not a tax determination. Runs entirely in your browser: nothing you enter is sent or stored.
Cost ratio = (total direct costs − direct costs of products made by prohibited foreign entities) ÷ total direct costs. For a battery component under 45X, the law counts direct material costs. The ratio must reach the minimum for your category and year, or the credit is lost to material assistance.
The calculator works out two cases. The best case assumes every "don't know yet" product turns out not to be made by a prohibited foreign entity; the worst case assumes they all are. Your real ratio sits somewhere in between. The wider that band, the more your answer depends on supplier diligence, and the calculator shows which unknown items would settle it.
What the calculator leaves out. The law's definitions of direct costs; Treasury's safe harbor cost tables (due by 31 December 2026) and the interim rules before them; the exception for products bought under binding contracts signed before 16 June 2025; relying on supplier certifications; and the separate test of whether the company claiming the credit is itself a prohibited foreign entity. Your tax adviser applies those.
Sources: 26 USC 7701(a)(52), as amended by Public Law 119-21; IRS Notice 2026-15. Rules current as of .
That's the question we answer from public records. Request a free supplier snapshot for one supplier, or see the buyer's quick guide.