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Mortgage Calculator South Carolina
Two identical South Carolina homes, two very different tax bills — one owner filed a form, the other didn't. This calculator asks which category applies to you before it gives you a number.
Estimate your South Carolina mortgage payment
Updates liveIllustrative estimate only. The 4% owner-occupied rate requires filing a Legal Residence application — see below. Not a loan offer or financial advice.
Diagram: the 4% rate is truly favorable — but it's not automatic, and a missed application means paying the 6% rate even while living in the home full-time.
Who checks this calculator
Understanding the South Carolina mortgage market
What makes a South Carolina mortgage different
South Carolina's property tax is truly low for owner-occupied homes — but that low rate depends on a specific application, not simply living there. This mortgage calculator South Carolina buyers use makes that distinction upfront.
The 4% vs 6% assessment ratio, explained
South Carolina assesses owner-occupied primary residences at just 4% of fair market value — one of the lowest assessment ratios of any state. Second homes, rental properties, and most other real estate are assessed at 6% instead. Because the local millage rate is the same regardless of which ratio applies, that 4% vs 6% gap translates directly into a 50% difference in tax bill between two otherwise identical properties, purely based on occupancy status.
Why the 4% rate isn't automatic
This is the detail that catches a lot of new buyers off guard: the 4% owner-occupied rate requires a one-time application with the county assessor's office, along with documentation proving the property is truly your legal primary residence — typically a South Carolina driver's license, voter registration, or similar proof tied to the property address. Skip this application, and the county will assess the home at the default 6% rate, even if you're living there full-time as your only residence. This mortgage calculator South Carolina tool assumes filed status only when you tell it to.
| Property type | Assessment ratio | Application required? |
|---|---|---|
| Owner-occupied legal residence | 4% | Yes, one-time filing with county assessor |
| Second home / rental / investment | 6% | Default, no application needed |
| Privately-owned agricultural | 4% | Separate agricultural use qualification |
Act 388 and the school tax exemption
Beyond the 4% ratio itself, Act 388 eliminated the school operating tax portion entirely for owner-occupied homes, with that lost revenue replaced by a one-percentage-point increase in the state sales tax (from 5% to 6%). This exemption applies automatically once a home is properly classified at the 4% legal-residence rate — no separate application is needed beyond the initial 4% filing. Non-owner-occupied properties, including rentals and second homes, still pay the full school operating tax along with everything else.
The 15% reassessment cap
South Carolina counties reassess property values on a five-year cycle, and state law caps how much a property's assessed value can increase during that reassessment to 15%, regardless of how much the actual market value rose during the interim. This truly limits sudden shocks for existing owners — even if a home's true market value doubled over five years, the taxable increase used for that reassessment cycle is capped at 15%.
Point-of-sale reassessment for new buyers
The 15% cap doesn't follow the property when it sells. An "assessable transfer of interest" — most commonly a sale — resets the property's value to current market value immediately, removing whatever protection the previous owner had accumulated. This is exactly why a new buyer can see a meaningfully different, often higher, first-year tax bill than what the seller was paying, even on the exact same house, simply because the seller's capped value doesn't transfer.
The senior homestead exemption
Homeowners aged 65 or older, legally blind, or permanently disabled can exempt the first $50,000 of their legal residence's fair market value from property tax entirely, stacking on top of the already-favorable 4% assessment ratio. Multiple bills proposing to raise this exemption to $100,000 have circulated in the 2025-2026 legislative session but hadn't been enacted as of the most recent check — worth watching if this applies to your situation.
A worked example, start to finish. Say a buyer purchases a $330,000 home in South Carolina as their primary residence, properly files the 4% Legal Residence application, and faces an effective tax rate around 0.53% (already reflecting the 4% ratio and typical local millage). With a 10% down payment, they're financing $297,000 at 6.6% over 30 years, giving a principal and interest payment of about $1,894.
Property tax adds roughly $146 a month, and with typical insurance, the full monthly payment comes to about $2,225. If this same buyer instead purchased the home as a second residence — or simply forgot to file the 4% application — the 6% ratio would apply instead, pushing the effective rate to roughly 0.80% and the monthly property tax to around $220, a real, meaningful $74-a-month difference purely from filing status.
How to use this mortgage calculator South Carolina tool
Enter the home price and down payment you're working with, along with your expected interest rate and loan term. Select your occupancy type — owner-occupied (4% ratio) or second home/rental (6% ratio) — and the property tax rate updates accordingly. Add an estimated annual insurance premium, and this mortgage calculator South Carolina shows your full estimated monthly payment.
Common mistakes to avoid
- Forgetting to file the 4% Legal Residence application. It's not automatic, even if you truly live in the home full-time.
- Assuming the seller's capped assessed value transfers to you. A sale triggers point-of-sale reassessment to full current market value.
- Confusing Act 388 with a full property tax exemption. It only eliminates the school operating tax portion, not the entire bill.
- Budgeting for a second home at the 4% rate. Non-owner-occupied properties default to the 6% ratio.
- Missing the senior homestead exemption if eligible. It's a separate application from the 4% legal residence filing.
Quick glossary
- Assessment ratio
- The percentage of fair market value used to calculate assessed value; 4% for owner-occupied legal residences, 6% for most other property.
- Legal Residence application
- The one-time filing required with a county assessor to qualify a home for the 4% owner-occupied assessment ratio.
- Act 388
- South Carolina legislation eliminating school operating tax for owner-occupied homes, funded by a state sales tax increase.
- 15% reassessment cap
- A limit on how much a property's assessed value can increase during a countywide five-year reassessment cycle.
- Assessable transfer of interest (ATI)
- An event, typically a sale, that resets a property's assessed value to current market value, removing the reassessment cap's accumulated protection.
The bottom line
South Carolina truly offers one of the most favorable property tax structures in the country for owner-occupied homes — but that favorable 4% rate depends entirely on filing the Legal Residence application, not simply living there. Confirm your county's specific millage rate, file the application as soon as you close, and this mortgage calculator South Carolina gives you a realistic, occupancy-aware starting point for what a home here actually costs each month.
Common questions