How Our Calculators Work
Every number in LeCPA's calculators traces to a primary IRS source, and every engine is updated when the law changes — not when someone happens to notice. This page documents the methodology, the data, and the results.
20
free calculators
covering entity choice, quarterly taxes, S-Corp savings, depreciation, retirement, and more
500+
client engagements
the calculators encode the same analysis we run for paying clients
$8,400
average first-year savings
across LeCPA tax-planning engagements (firm data, as reported 2026)
$2M+
total client savings
cumulative tax savings identified for DFW clients since 2014
Data sources
Calculator engines are driven by versioned tax-year data files. Each value carries an inline citation to its authoritative source:
- IRS Revenue Procedure 2025-32 — 2026 inflation adjustments (brackets, standard deduction, AMT, capital gains)
- IRS Revenue Procedure 2024-40 — 2025 inflation adjustments
- One Big Beautiful Bill Act (P.L. 119-21) — permanent TCJA rates, QBI, SALT cap, bonus depreciation
- IRS Notice 2025-67 — 2026 retirement plan limits
- SSA 2026 Fact Sheet — Social Security wage base ($184,500)
- IRS Publication 946 — depreciation (MACRS tables)
- IRS Publication 505 — withholding and estimated tax (safe harbor rules)
Update policy
When tax law changes, the engines change. After the One Big Beautiful Bill Act (July 2025) repealed the scheduled TCJA sunset, every affected calculator was rebuilt on the permanent-law values — brackets, QBI, the expanded SALT cap and its 2030 reversion, 100% bonus depreciation, and the new AMT phase-out rules. Annual IRS inflation adjustments are applied when the Revenue Procedure for the year is published each fall.
Accuracy and limits
The calculation engines are covered by 350+ automated tests validated against IRS publication examples, and results are reviewed by Krystal Le, CPA (Texas-licensed). Calculators produce planning estimates, not tax advice: they simplify items like multi-state income, credits, and unusual situations. For decisions with real money attached, confirm your numbers with a CPA.