Iowa take-home pay

TY2026 rate held at 3.8% per IDR press release 2025-10-21. Standard deduction federal-conforming under §422.9 — TY2026 figures reflect Rev. Proc. 2025-32 ($16,100 / $32,200 / $16,100 / $24,150). **Personal-exemption-credit encoding**: $40 per personal credit + $40 per dependent. Iowa applies the HoH-as-2-personal-credits convention (per IA-1040 Step 3 line a's verbatim instruction "enter 2 if filing status 2 or 4" where status 2 = MFJ, status 4 = HoH), encoded via the twoTaxpayerStatuses override on PersonalExemptionCreditTable. CA's HoH-as-1-credit convention is the schema default and is unaffected. **Iowa QSS handling**: Iowa's Step 3 instruction states QSS (filing status 5) takes 1 personal credit ($40), but the calculator's 4-status enum maps QSS → MFJ → 2 credits ($80) per CLAUDE.md QSS-to-MFJ heuristic. Documented overstatement of ~$40/yr in IA credit for QSS filers. **Not modeled**: age 65+ / blind extra credits ($20 each per IA-1040 Step 3 line b). No local income taxes in IA. TY2026 IA-1040 booklet expected to publish ~Jan-Feb 2027; encoded figures will be re-verified at that time.