Methodology

The tax being modeled

Greenville County Council adopted the enacting ordinance on July 21, 2026 (8–3), placing a 1% transportation sales tax on the November 3, 2026 ballot under S.C. Code § 4-37-30 (Title 4, Ch. 37, “Optional Methods for Financing Transportation Facilities”). The rate piggybacks on the state sales tax base defined in Title 12, Chapter 36, with specific carve-outs.

The tax collects for a maximum of eight years from the date of imposition, which the ordinance sets at May 1, 2027 (§2.2, §2.5). It can end sooner: collection stops if the tax raises the $1,100,000,000 the ballot names (§2.6). Continuing it past that point would require a new public vote.

County allocation shown in the comparison

Question 1 prints a ceiling for each county purpose: no more than $990,000,000 for roads, bridges, other transportation-related projects and related drainage; $33,000,000 for mass transit; and $77,000,000 for greenbelts. Together they equal the ballot’s $1,100,000,000 cap. The comparison table expresses those ceilings as shares of that total: 990 ÷ 1,100 = 90%, 33 ÷ 1,100 = 3%, and 77 ÷ 1,100 = 7%. They are ceilings, not guaranteed spending shares or floors.

Source: Greenville Journal’s contemporaneous report of the adopted ballot question. The governing ordinance provisions are §2.4(i)–(iii) and §5.2, Question 1, Projects (1)–(3).

What is taxed and what is exempt

Exempt by state statute

• Motor fuel (gasoline, diesel): § 12-36-2120(15)
• Prescription drugs: § 12-36-2120(28)
• Residential electricity, natural gas, and fuel oil: § 12-36-2120(33)
• Water sold by public utilities: § 12-36-2120(12)
• Home internet access: exempt under the federal Internet Tax Freedom Act (P.L. 114-125, made permanent in 2016). State and local governments are preempted from taxing internet access charges. Note: this applies only to the broadband access line itself, not to streaming subscriptions or cable TV, which are taxed.
• Max-tax items (vehicles, motorcycles, boats, aircraft, recreational vehicles, manufactured homes) are capped at $500 total state sales tax under § 12-36-2110, and § 4-37-30 itself exempts them from a transportation tax (“exempt from the tax imposed by this section”). Vehicles registered with SCDMV pay the infrastructure maintenance fee instead (§ 56-3-627) and are exempt from sales tax under § 12-36-2120(83).

Exempt under the adopted ordinance (§2.9)

Unprepared groceries. At the July 21, 2026 final reading, Council adopted the ordinance's §2.9 amendment, electing the broad unprepared-food exemption under § 4-37-30(A)(9): unprepared food items eligible for USDA food coupons, exempt for all buyers, not only SNAP recipients. Motor fuel, prescription drugs, medicine, and prosthetic devices are also confirmed exempt under the adopted ordinance. The calculator treats groceries as exempt throughout, matching the adopted text.

Taxed

Everything else that is subject to the state sales tax: prepared food (restaurants, takeout), clothing, furniture, appliances, electronics, alcoholic beverages, tobacco products, telecommunications services, pet supplies, personal care products, books, magazines, and general retail. Event admissions are not on this list: tickets to movies, concerts, games, and attractions pay the state’s separate 5% admissions license tax (§ 12-21-2420), not the sales tax this measure piggybacks on.

Spending data

Each slider is one category of household monthly spending. The default values are the category's typical amount for a household at the selected income level. Dragging a slider directly edits what you spend on that category; the tax is recomputed live.

Default spending values blend two sources:

• BLS Consumer Expenditure Survey, Table 1203 (2024, published December 2025) provides the structural baseline and income-bracket scaling for clothing, furnishings, alcohol, vehicle maintenance, personal care, and small retail. Source
• 2025–2026 consumer research replaces BLS for categories where BLS lags reality by two or more years. Cell phone service, streaming/cable, and dining out all show gaps between what BLS reports and what current data captures.

Where this model diverges from BLS

• Cell phone, cable & streaming (one combined slider): BLS 2024 averages around $110/month for phone service and buries streaming inside "Entertainment," missing recent price hikes. Current industry data runs higher: J.D. Power's Q1 2025 data and Astound's 2026 analysis put family mobile plans at $130–160/month, and Deloitte's 2026 Digital Media Trends report puts streaming at $69/month (Netflix, Hulu, YouTube TV, etc.) plus $80 to $120/month for households that still have cable. The slider's $225/month default at the $77k preset blends mobile ($130 to $160) with streaming ($60 to $90). It does not assume cable.
• Dining out: Empower's 2025 "The Currency" tracking puts the median US household at ~$330/month on food away from home. BLS (which includes lower-income households) reports about $284/month for the $70–100k bracket. The $77k preset's $350 default sits above Empower's national median because the preset is interpolated at Greenville County's median income, which is higher than the US median.
• Entertainment & hobbies (excluding streaming): pets, hobbies, toys, sporting goods, gym memberships. Admissions are excluded entirely: tickets to movies, concerts, games, and attractions pay the 5% admissions license tax (§ 12-21-2420), not the Chapter 36 sales tax this measure piggybacks on. Untaxed pet services and some club dues net the remainder down further, so the category is weighted at 55% taxable.

The $42k, $150k, and $200k+ presets use bracket averages from the national BLS columns below. The $77k preset is anchored at $76,932, Greenville County's median household income (Census ACS 2020–2024 5-year estimate, table B19013); its spending defaults are the model's own log-linear interpolation at that income, frozen as curated values, drawn against the same $70,000–$99,999 BLS column. For custom income amounts, each category is log-linearly interpolated between the two adjacent presets.

Two disclosures on the median anchor. First, the BLS brackets are national consumer-unit brackets. The CE survey's unit is not exactly a "household," and no CE data exists for Greenville County or its metro area, so the model applies national spending patterns at the local median income rather than implying local spending data. Second, the Census also publishes a 2024 1-year median of $82,648 for Greenville County; the model returns $153 at that income, inside the published $145–$170 range. We anchor on the 5-year estimate because it is the larger sample the Census recommends for county-level figures.

Income brackets used

The $200k+ button represents the BLS open-ended top bracket, whose mean income is $322,142 because it includes all households above $200k. We label it "$200k+" rather than "$300k" to match the source data.

Interpolation between brackets

For custom income amounts between presets, the calculator uses log-linear interpolation on each spending category. Engel curves (the relationship between income and spending on a category) are concave, not linear, so straight-line interpolation would overstate tax for incomes near the top of a bracket and understate near the bottom. Log-linear interpolation preserves the shape of the underlying data.

Taxable fractions per category

Some BLS spending categories lump together taxable and non-taxable sub-items. Treating such a category as fully taxed would overstate the tax. Every slider category carries an explicit taxable fraction. This table matches the values in the calculator's data file exactly. Three categories are down-weighted below 100%:

The fixed "Other taxed retail" line is built the same way, with the adjustment pre-applied to its dollar estimate rather than expressed as a runtime fraction: it combines housekeeping supplies, OTC medical supplies, and reading material with the taxable portion (roughly one quarter) of the BLS Miscellaneous line, which mostly bundles finance charges, legal fees, and cash contributions that are not taxable retail.

The exempt utilities line

The spending breakdown shows a household's combined monthly cost for water, electricity, and natural gas alongside the taxed categories. This line adds nothing to the tax estimate. It shows how much of the monthly budget the tax does not reach. Residential electricity and natural gas are exempt under § 12-36-2120(33); water sold by public utilities is exempt under § 12-36-2120(12).

The amounts come straight from BLS CEX 2024 Table 1203: the annual means for Electricity, Natural gas, and Water and other public services, summed and divided by twelve ($238/mo at the $42k preset, $273 at $77k, $326 at $150k, $385 at $200k+). The BLS "Water and other public services" line also includes trash collection and septic service, so the displayed lump slightly overstates pure water spending.

Sanity check against Charleston County

Charleston County has collected a 0.5% transportation sales tax under § 4-37-30 since 2004. An audit released December 2025 reported collections of approximately $767 million over 2019–2024, or roughly $153 million per year at the 0.5% rate. Doubled to a 1% equivalent, that is ~$307 million per year.

Charleston County has 178,975 households (Census ACS 2020–2024 5-year estimate, table B11001). A naive division would yield $1,715/household/year at 1%, but that overstates the true per-household burden because:

• Charleston has substantial tourism. Charleston's transportation program office reports roughly 30% of collections come from non-residents.
• Sales tax collections also include business-to-business purchases of construction materials, equipment, and supplies, which are not household spending.
• We assume the resident household share of total collections is 35 to 45%.

Applying a 40% resident household share:

$307M × 40% ÷ 178,975 households = ~$686/household/year at 1%

Charleston's median household income is $88,494, which is about 15% higher than Greenville County's $76,932. Both figures come from the same Census release, the ACS 2020–2024 5-year estimate, table B19013, so the comparison is not reading a gap that is really a difference in vintage. Adjusting downward for income (higher income households buy more taxable goods), a comparable Greenville estimate would be approximately $596/household/year at the median ($686 ÷ 1.15 ≈ $596). Dividing is the right move here, not subtracting 15%: Charleston is 15% above Greenville, so removing that gap means undoing the multiplication that created it.

That $596 is a ceiling, not a prediction. The 40% resident-household share is a round assumption rather than a measurement, so the figure it produces still contains business-to-business purchases and tourism spending that no household pays, and Greenville draws much less tourism than Charleston. The calculator's estimate of about $146/year for a median-income household (groceries exempt) sits well below that ceiling, reflecting the conservative taxable-fraction choices above.

The combined outlook for city voters

Some readers live in a city with its own 1% sales tax question on the same November ballot. They see a short block for what both measures together would mean for their household. The answer is a range, never a single number. Its low end is a household that buys nothing taxable inside the city. Its high end is one that buys everything taxable inside the city. Every real household falls between them. A city homeowner's property tax credit comes off both ends.

A city's 1% falls on the same Title 12, Chapter 36 purchases as the county's, at the same rate, and every city with a measure sits inside the county, so a household's city sales tax cannot exceed its county sales tax. The county figure above is therefore the ceiling. The floor is $0, since a household that buys nothing taxable inside the city limits pays that city nothing. Both ends are definitional, so every possible in-city share falls between them.

The credit is the city's, computed from its own published rate, which the panel links. Collections start partway through a year, so the range uses the city's first full-year credit, not the smaller partial one. Subtracting it from both ends gives the range the panel shows:

combined = [ county − credit , (2 × county) − credit ]

Renters, and owners whose home is not a primary residence, get no credit, so their range runs from the county estimate up to twice it. One more limit applies to a smaller group. The credit is nonrefundable and offsets only municipal tax a household actually owes (§ 5-41-120(C)(3)), but it is computed on the home’s value before the § 12-37-250 homestead exemption (§ 5-41-170(A)(1)). That exemption removes the first $50,000 of value from municipal tax for owners who are 65 or older, blind, or disabled. For those owners on a lower-valued home the credit is therefore capped at the bill it offsets, and below $50,000 of taxable value there is no municipal liability and so no usable credit. This calculator does not ask whether you hold that exemption, so the credit it shows is the uncapped figure the city’s own table gives.

The break-even shown beside each credit is ours, not the city's:

break-even = credit ÷ rate

It is derived from the unrounded credit and rounded once. Travelers Rest publishes a table of per-home credits by taxable home value, and the coefficient behind it.

What this calculator does not model

• Spending variation within a bracket. Two households at the same income can pay very different amounts depending on whether they dine out, smoke, drink, own pets, or travel. The calculator shows the average for the bracket, not what you personally will pay.
• Major one-time purchases. A household buying a new couch, a new laptop, or furnishing a first apartment will pay more in that year than the annual average.
• Tourism and business spending. Some share of the total tax collected by the county will come from visitors and businesses, not residents. This calculator only estimates the resident household share.
• Regional price differences. BLS national data does not capture Greenville-specific price levels or shopping patterns.

Limitations and caveats

• The grocery exemption is adopted ordinance text (§2.9, adopted at the July 21, 2026 final reading); the model matches it.
• The $200k+ bracket is open-ended and averages in ultra-high-income households. The $200k+ button is appropriate for a single estimate at that level but cannot distinguish a $250k household from a $500k household. Use the custom input for more precision.
• Custom incomes below $42,000 or above the top bracket use the nearest bracket's averages rather than extrapolating further.
• The $42k/$77k/$150k custom-income interpolation is anchored at the preset incomes ($42,000 / $76,932 / $150,000), not at the BLS bracket means shown in the table above (e.g., $83,888 for the $77k tile). A household entering its literal $83,888 income is interpolated partway toward the $150k tile rather than centered on its own bracket's average. Both are defensible readings of the same data.
• Treat this as an estimate built on averages, not a bill. The only way to know exactly what you will pay is to track your own taxable purchases for a year.
• Source data is the 2024 calendar year, released by BLS in December 2025. Updates in future years will use the same methodology applied to newer data.

Sources

Statutes and official guidance

• S.C. Code § 4-37-30: Title 4, Ch. 37, "Optional Methods for Financing Transportation Facilities"
• S.C. Code Title 12, Chapter 36: sales and use tax base and exemptions
• SC DOR Sales & Use Tax Manual: official DOR guidance on exemptions
• Internet Tax Freedom Act: federal preemption on taxing internet access

Spending data

• BLS Consumer Expenditure Survey tables (Table 1203, 2024)
• J.D. Power TV & Internet Bills Q1 2025
• Reviews.org State of Consumer Media Spending 2025
• Astound Average Cell Phone Bill 2026
• Deloitte Digital Media Trends 2026
• Empower, America’s Food Spending 2025
• AAA, Your Driving Costs 2025 (vehicle maintenance average)

Greenville and sanity checks

• US Census: Greenville County, SC
• Charleston County Transportation Development

Every source on this page is public, and every assumption is stated where it is used.

Last updated: August 17, 2026.