Methodology, Formulas, and Guidance

This calculator applies Mississippi’s phased flat-rate schedule to Mississippi taxable income. Use the Detailed mode if you need help estimating taxable income from gross income.

Data Source and Methodology

Authoritative Data Source: Mississippi Department of Revenue — Individual Income Tax Rate Changes (HB 531, 2022) and annual instructions. Effective rates used: 2024: 0% on first $10,000 of taxable income; 4.7% above. 2025: 0% on first $10,000; 4.4% above. 2026+: 0% on first $10,000; 4.0% above.

  • Mississippi Department of Revenue — Individual Income Tax: Rate Reduction Overview (HB 531, 2022). Date: 2022; effective tax years 2024–2026. Link: https://www.dor.ms.gov/
  • Mississippi Individual Income Tax Instructions (annual, e.g., Form 80-105). See the current year’s PDF for deductions and exemptions details. Link: https://www.dor.ms.gov/individual

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The Formulas Explained

Taxable income (Detailed mode): TI = max(0, GI - Adj - DedEx)

Rate by year: r(y) = { 0.047 if y = 2024; 0.044 if y = 2025; 0.040 if y ≥ 2026 }

Mississippi tax (piecewise): T(y, TI) = { 0 if TI ≤ 10{,}000; r(y) · (TI - 10{,}000) if TI > 10{,}000 }

Effective tax rate (relative to gross income GI, when GI > 0): ETR = T / GI
Marginal tax rate: MTR = { 0 if TI ≤ 10{,}000; r(y) if TI > 10{,}000 }

Glossary of Variables

GI: Annual gross income before pre-tax adjustments.
Adj: Pre-tax adjustments (e.g., 401(k), HSA) that reduce income.
DedEx: Mississippi deductions and exemptions (sum of standard/itemized deduction, personal exemptions, and MS-specific exclusions).
TI: Mississippi taxable income. Input directly in Quick mode or computed in Detailed mode.
T: Mississippi state income tax owed based on TI and year y.
ETR: Effective tax rate (state tax divided by gross income).
MTR: Marginal tax rate for the next dollar of taxable income.
r(y): The flat rate applied to TI above $10,000 for the selected year.

How It Works: A Step-by-Step Example

Scenario: Year = 2024, filing status = Single, GI = $65,000, Adj = $3,000, DedEx = $12,000.

  1. Compute taxable income: TI = max(0, 65,000 − 3,000 − 12,000) = 50,000.
  2. Apply 2024 rate schedule: - First $10,000 at 0% → $0. - Above $10,000: (50,000 − 10,000) × 0.047 = 40,000 × 0.047 = $1,880.
  3. Mississippi tax due: T = $1,880.
  4. Effective tax rate: ETR = 1,880 / 65,000 ≈ 2.89%.
  5. After-tax income (state only): 65,000 − 1,880 = $63,120.

Note: This example assumes you correctly summed Mississippi-allowed deductions and exemptions in DedEx.

Frequently Asked Questions (FAQ)

What are Mississippi’s state income tax rates for 2024–2026?

0% on the first $10,000 of taxable income. For the portion above $10,000: 4.7% in 2024, 4.4% in 2025, and 4.0% in 2026 and later.

Does filing status change the rate thresholds?

The rate thresholds are the same for taxable income regardless of filing status. However, filing status can impact your deductions and exemptions that determine taxable income.

Which income should I enter in Quick mode?

Enter your Mississippi taxable income (after Mississippi-specific deductions and exemptions). If you’re unsure, switch to Detailed mode to estimate it from your gross income.

Are retirement benefits or Social Security taxed?

Mississippi excludes Social Security from taxable income. Certain retirement income may also be excluded—consult the latest Mississippi DOR instructions to see what applies.

Can I itemize deductions for Mississippi?

Yes, subject to Mississippi rules. In this tool, include your Mississippi itemized amount (instead of the standard deduction) in the DedEx field if you itemize.

Is this calculator legal or tax advice?

No. It is an educational tool. For an exact filing position, consult the Mississippi Department of Revenue or a qualified tax professional.

Tool developed by Ugo Candido. Content verified by CalcDomain Editorial Team.
Last reviewed for accuracy on: .