{
  "slug": "quarterly-estimated-tax-calculator",
  "title": "Quarterly Estimated Tax Calculator",
  "heading": "Quarterly Estimated Tax Calculator",
  "category": "financial",
  "url": "https://www.revenuelab.fyi/toolbox/quarterly-estimated-tax-calculator",
  "summary": "What to send the IRS each quarter to stay inside the safe harbor.",
  "description": "Anyone with income that is not subject to withholding — freelancers, landlords, creators, investors, S-corp owners taking distributions — has to pay tax as they earn it or face an underpayment penalty computed as interest on each missed instalment. The practical target is not a perfect forecast, it is a safe harbor: pay at least 90% of this year's tax or 100% of last year's tax (110% if your prior-year adjusted gross income exceeded $150,000) and the penalty disappears even if you owe a large balance in April. This calculator estimates income tax and self-employment tax on your projected net earnings, subtracts withholding from any W-2 job, applies both safe harbor tests, and reports the smaller required amount split into the four instalments the IRS expects. It also shows the balance likely due at filing so you can decide whether to overpay slightly for comfort. State estimates are separate and often on different dates — check your state's schedule.",
  "formula": "Required = min(90% × Current-Year Tax, Safe Harbor % × Prior-Year Tax) − Withholding. Quarterly = Required ÷ 4.",
  "dateModified": "2026-09-06",
  "run_url": "https://www.revenuelab.fyi/api/public/calc?tool=quarterly-estimated-tax-calculator",
  "inputs": [
    {
      "id": "netProfit",
      "label": "Projected self-employment net profit",
      "kind": "number",
      "hint": null,
      "default": 85000,
      "unit": "$",
      "min": 0,
      "max": 2000000
    },
    {
      "id": "otherIncome",
      "label": "Other income (W-2, interest, rent)",
      "kind": "number",
      "hint": null,
      "default": 0,
      "unit": "$",
      "min": 0,
      "max": 5000000
    },
    {
      "id": "withholding",
      "label": "Tax already withheld this year",
      "kind": "number",
      "hint": null,
      "default": 0,
      "unit": "$",
      "min": 0,
      "max": 500000
    },
    {
      "id": "deductions",
      "label": "Standard or itemised deduction",
      "kind": "number",
      "hint": null,
      "default": 15000,
      "unit": "$",
      "min": 0,
      "max": 200000
    },
    {
      "id": "effectiveRate",
      "label": "Effective federal income tax rate",
      "kind": "number",
      "hint": null,
      "default": 14,
      "unit": "%",
      "min": 0,
      "max": 40
    },
    {
      "id": "priorYearTax",
      "label": "Total tax on last year's return",
      "kind": "number",
      "hint": null,
      "default": 16000,
      "unit": "$",
      "min": 0,
      "max": 1000000
    },
    {
      "id": "priorAgi",
      "label": "Last year's AGI",
      "kind": "number",
      "hint": null,
      "default": 120000,
      "unit": "$",
      "min": 0,
      "max": 5000000
    },
    {
      "id": "ssWageBase",
      "label": "Social Security wage base",
      "kind": "number",
      "hint": null,
      "default": 176100,
      "unit": "$",
      "min": 100000,
      "max": 300000
    }
  ],
  "outputs": [
    {
      "id": "quarterly",
      "label": "Send each quarter",
      "format": "currency",
      "hint": null,
      "primary": true
    },
    {
      "id": "required",
      "label": "Total estimated payments required",
      "format": "currency",
      "hint": null,
      "primary": false
    },
    {
      "id": "currentTax",
      "label": "Projected total tax",
      "format": "currency",
      "hint": null,
      "primary": false
    },
    {
      "id": "seTax",
      "label": "Self-employment tax",
      "format": "currency",
      "hint": null,
      "primary": false
    },
    {
      "id": "incomeTax",
      "label": "Federal income tax",
      "format": "currency",
      "hint": null,
      "primary": false
    },
    {
      "id": "balanceDue",
      "label": "Likely balance due at filing",
      "format": "currency",
      "hint": null,
      "primary": false
    },
    {
      "id": "safeHarborPct",
      "label": "Safe harbor percentage applied",
      "format": "percent",
      "hint": null,
      "primary": false
    }
  ],
  "worked_example": {
    "inputs": [
      "Projected self-employment net profit: 85000 $",
      "Other income (W-2, interest, rent): 0 $",
      "Tax already withheld this year: 0 $",
      "Standard or itemised deduction: 15000 $",
      "Effective federal income tax rate: 14 %",
      "Total tax on last year's return: 16000 $",
      "Last year's AGI: 120000 $",
      "Social Security wage base: 176100 $"
    ],
    "outputs": [
      "Send each quarter: $4,000",
      "Total estimated payments required: $16,000",
      "Projected total tax: $20,969",
      "Self-employment tax: $12,010",
      "Federal income tax: $8,959",
      "Likely balance due at filing: $4,969",
      "Safe harbor percentage applied: 100%"
    ]
  },
  "how_to": {
    "title": "How to use this",
    "steps": [
      "Enter projected self-employment net profit ($).",
      "Enter other income (w-2, interest, rent) ($).",
      "Enter tax already withheld this year ($).",
      "Enter standard or itemised deduction ($).",
      "Enter effective federal income tax rate (%).",
      "Enter total tax on last year's return ($).",
      "Enter last year's agi ($).",
      "Enter social security wage base ($).",
      "Read your send each quarter on the right — it updates as you type.",
      "Hit Share to keep the scenario or send it to someone."
    ]
  },
  "scenarios": [
    {
      "name": "Conservative",
      "description": "Lower-end numbers — what if things land soft?",
      "values": {
        "netProfit": 51000,
        "otherIncome": 0,
        "withholding": 0,
        "deductions": 9000,
        "effectiveRate": 8.4,
        "priorYearTax": 9500,
        "priorAgi": 70000,
        "ssWageBase": 105700
      }
    },
    {
      "name": "Typical",
      "description": "Defaults — the most common real-world setup.",
      "values": {
        "netProfit": 85000,
        "otherIncome": 0,
        "withholding": 0,
        "deductions": 15000,
        "effectiveRate": 14,
        "priorYearTax": 16000,
        "priorAgi": 120000,
        "ssWageBase": 176100
      }
    },
    {
      "name": "Ambitious",
      "description": "Higher-end numbers — what if things really pop?",
      "values": {
        "netProfit": 136000,
        "otherIncome": 0,
        "withholding": 0,
        "deductions": 24000,
        "effectiveRate": 22.400000000000002,
        "priorYearTax": 25500,
        "priorAgi": 190000,
        "ssWageBase": 281800
      }
    }
  ],
  "limitations": [
    "Results are estimates before tax, fees, and inflation unless an input explicitly covers them.",
    "Rates are treated as fixed for the whole period — variable-rate products will drift from this projection.",
    "This is educational maths, not financial advice. Check anything contractual with the lender or your accountant."
  ],
  "faq": [
    {
      "q": "When are the payments due?",
      "a": "For calendar-year taxpayers the federal instalments are generally due in mid-April, mid-June, mid-September, and mid-January of the following year. The periods are uneven, which is why the June payment covers only two months."
    },
    {
      "q": "Can I just pay it all in the fourth quarter?",
      "a": "Not without a penalty. The underpayment penalty is calculated per period, so a large January payment does not cure missed April and June instalments unless you use the annualised income method on Form 2210."
    },
    {
      "q": "What if my income is seasonal?",
      "a": "Use the annualised income instalment method, which lets you pay in proportion to when you actually earned the money. It requires more record-keeping but can eliminate penalties for a business with a lumpy year."
    },
    {
      "q": "Is withholding better than estimates?",
      "a": "Often yes. Withholding is treated as paid evenly across the year regardless of when it happens, so increasing withholding late in the year through a W-2 job or a retirement distribution can retroactively fix an underpayment."
    }
  ],
  "related": [
    "https://www.revenuelab.fyi/toolbox/s-corp-vs-llc-tax-savings-calculator",
    "https://www.revenuelab.fyi/toolbox/llc-formation-cost-calculator"
  ],
  "license": "CC-BY-4.0",
  "citation": "RevenueLab — Quarterly Estimated Tax Calculator (https://www.revenuelab.fyi/toolbox/quarterly-estimated-tax-calculator)"
}