{"model":"quarterly-estimates","specVersion":"1.0.0","specUrl":"/api/v1/models/quarterly-estimates/spec","inputs":{"expectedCurrentYearTax":{"kind":"float","min":0,"max":500000},"priorYearTax":{"kind":"float","min":0,"max":500000},"priorYearAgi":{"kind":"float","min":0,"max":3000000},"expectedWithholding":{"kind":"float","min":0,"max":500000}},"arrayInputs":{},"constraints":["IRC §6654 safe harbors with the non-MFS 110% AGI trigger ($150,000); four equal installments — the annualized-income method is out of scope."],"sentinels":[],"facts":[{"id":"irs.6654.safe-harbor.current-year-pct","label":"Estimated-tax safe harbor: share of current-year tax","value":0.9,"period":"statutory (IRC §6654(d)(1)(B)(i), not indexed)","source":"IRC §6654(d)(1)(B)(i); IRS Form 1040-ES instructions"},{"id":"irs.6654.safe-harbor.prior-year-pct","label":"Estimated-tax safe harbor: share of prior-year tax (AGI ≤ $150,000)","value":1,"period":"statutory (IRC §6654(d)(1)(B)(ii), not indexed)","source":"IRC §6654(d)(1)(B)(ii); IRS Form 1040-ES instructions"},{"id":"irs.6654.safe-harbor.prior-year-pct.high-agi","label":"Estimated-tax safe harbor: share of prior-year tax when prior-year AGI exceeds $150,000","value":1.1,"period":"statutory (IRC §6654(d)(1)(C), not indexed)","source":"IRC §6654(d)(1)(C); IRS Form 1040-ES instructions"},{"id":"irs.6654.high-agi-threshold","label":"Estimated-tax safe harbor: prior-year AGI threshold for the 110% rule","value":150000,"period":"statutory (IRC §6654(d)(1)(C)(i), not indexed)","source":"IRC §6654(d)(1)(C)(i); IRS Form 1040-ES instructions"},{"id":"irs.6654.de-minimis-balance","label":"Estimated-tax de minimis: no payments required when balance after withholding is under this","value":1000,"period":"statutory (IRC §6654(e)(1), not indexed)","source":"IRC §6654(e)(1); IRS Form 1040-ES instructions"}],"disclaimer":"Illustrative planning model, not financial advice. Outputs follow the published model spec exactly; read the spec for assumptions and exclusions before relying on any number."}