US Net Investment Income Tax (NIIT) Estimator (Section 1411)
Threshold amounts for NIIT are set by law and do not change annually (since enactment).
Select the filing status you will use for the tax year.
Enter your calculated MAGI (generally AGI + certain foreign earned income exclusion). This tool does NOT calculate MAGI.
Enter your calculated NII (Investment income less certain deductions). NII can be negative. This tool does NOT calculate NII.
Estimated Net Investment Income Tax (NIIT):
- The NIIT rate is 3.8%.
- The tax is imposed on the **lesser** of your Net Investment Income (NII) or the amount by which your Modified Adjusted Gross Income (MAGI) exceeds the applicable threshold amount for your filing status.
- Threshold amounts are: $250,000 (MFJ/Qualifying Widow(er)), $125,000 (MFS), $200,000 (Single/Head of Household/Certain NRAs). These thresholds are NOT indexed for inflation.
- This tool requires you to input your already calculated NII and MAGI. It does NOT calculate NII or MAGI.
- Consult Form 8960 and its instructions for detailed rules on calculating NII and MAGI for NIIT purposes and for exceptions.
Estimated Net Investment Income Tax (NIIT): ${formatCurrency(estimatedNiit)}
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`; niitResultsDiv.style.display = 'block'; downloadPdfBtn.style.display = 'none'; // Hide PDF button on error } function displayResults(resultsHtml) { niitResultsContentDiv.innerHTML = resultsHtml; niitResultsDiv.style.display = 'block'; downloadPdfBtn.style.display = 'block'; // Show PDF button on successful calculation } function downloadPdf() { // Ensure jsPDF is loaded if (typeof window.jspdf === 'undefined') { console.error('jsPDF library not loaded.'); alert('PDF generation library not loaded. Please try again.'); return; } const { jsPDF } = window.jspdf; const doc = new jsPDF(); let yPos = 15; // Starting Y position const margin = 15; // Title doc.setFontSize(18); doc.setTextColor(0, 86, 179); // RGB for #0056b3 (Accent color) doc.text('US Net Investment Income Tax (NIIT) Estimator', margin, yPos); yPos += 20; // Get the content from the results section const resultsContentDiv = document.getElementById('niit_results_content'); if (!resultsContentDiv || resultsContentDiv.innerHTML.trim() === '' || resultsContentDiv.textContent.includes('Error:')) { doc.setFontSize(12); doc.setTextColor(51, 51, 51); doc.text('No NIIT estimation results available or an error occurred.', margin, yPos); doc.save(`niit_estimate.pdf`); return; } // Add Results to PDF - manually adding lines, handling bolding doc.setFontSize(10); doc.setTextColor(51, 51, 51); // Text color // Get the content including the H4 heading and paragraphs const resultElements = resultsContentDiv.querySelectorAll('h4, h5, p'); // Should only be paragraphs in the content div after H4/H5 resultElements.forEach(element => { let lineText = element.textContent.trim(); if (lineText) { // Identify strong tags for potential bolding const strongElement = element.querySelector('strong'); const strongText = strongElement ? strongElement.textContent.trim() : ''; const splitText = doc.splitTextToSize(lineText, 180); splitText.forEach((segment, index) => { let currentX = margin; // Attempt to bold the beginning of the segment if it matches the strong text if (strongText && segment.startsWith(strongText)) { // Check if the segment *starts* with the strong text const boldPart = strongText; const normalPart = segment.substring(strongText.length); if (boldPart) { doc.setFont(undefined, 'bold'); doc.text(boldPart, currentX, yPos); currentX += doc.getTextWidth(boldPart); } if (normalPart) { doc.setFont(undefined, 'normal'); doc.text(normalPart, currentX, yPos); } } else { // No bolding needed for this segment or it's not the start of the strong text doc.setFont(undefined, 'normal'); // Ensure normal font doc.text(segment, currentX, yPos); } yPos += 7; // Move to the next line segment position }); yPos += 3; // Extra space between paragraphs } }); // Add the Note section explicitly from the HTML const noteElement = document.querySelector('#niit_results > .note'); // Note is directly in results-section if (noteElement) { yPos += 15; // Space before note doc.setFontSize(9); doc.setTextColor(85, 85, 85); // RGB for #555 (Note color) const noteText = noteElement.textContent.trim(); const splitNote = doc.splitTextToSize(noteText, 180); doc.text(splitNote, margin, yPos); // yPos += (splitNote.length * 6); // Space after note } // Save the PDF const year = taxYearInput.value.trim() || 'Estimate'; doc.save(`niit_estimate_${year}.pdf`); } // Initial state setup niitResultsDiv.style.display = 'none'; // Hide results initially downloadPdfBtn.style.display = 'none'; // Hide PDF button initially // Set default year to current year const currentYear = new Date().getFullYear(); taxYearInput.value = currentYear; });The US Net Investment Income Tax (NIIT) Estimator (Section 1411) is a valuable tool for taxpayers seeking to understand and calculate the additional 3.8% tax imposed on certain investment income under IRS Section 1411. This tax applies to individuals, estates, and trusts with modified adjusted gross income (MAGI) above specific thresholds, helping you plan your finances better by estimating your potential NIIT liability.
NIIT applies to investment income such as interest, dividends, capital gains, rental income, royalties, and passive business income. The tax kicks in once your MAGI exceeds $200,000 for single filers, $250,000 for married filing jointly, and other filing status thresholds. Because NIIT is a relatively new tax provision, many taxpayers may overlook its impact, potentially leading to unexpected tax liabilities.
Our estimator simplifies this complex calculation by allowing you to input your MAGI, investment income, and filing status. It quickly computes your estimated NIIT, helping you make informed decisions about investment timing, income planning, and tax strategies to minimize this additional tax burden.
Understanding your NIIT liability is critical for high-income earners, investors, real estate owners, and professionals managing passive income sources. With this tool, you can identify tax planning opportunities, such as adjusting income recognition or optimizing investment portfolios to reduce taxable income under Section 1411.
Regular use of the NIIT Estimator ensures you stay compliant with tax laws while maximizing after-tax returns. It also serves as a helpful resource for tax professionals advising clients on managing investment income effectively.
Use our US Net Investment Income Tax (NIIT) Estimator today to gain clear insights into your Section 1411 tax liability and make smarter financial decisions.
