Statutory Accuracy & Source Verification

Every rate, component breakdown, and effective date served by the Ohio Sales Tax API is backed by continuous reconciliation against official state tax records.

Authoritative Data Sources

1. Ohio Department of Taxation (ODT) — The Finder

Our rate engine reconciles continuously against the official state database:

Portal: The Finder (thefinder.tax.ohio.gov)
Frequency: Continuous automated verification scans and weekly manual reconciliations.
Coverage: All 88 Ohio counties, municipal boundaries, and school district codes.

2. Board of County Commissioners Permissive Levies

Under Ohio R.C. § 5739.021 and § 5739.026, county commissioners may enact permissive sales taxes in increments of 0.10% or 0.25% up to the statutory cap of 1.50%:

Rate changes can only become effective on the first day of a calendar quarter (Jan 1, Apr 1, Jul 1, Oct 1).
Requires at least 60 days advance statutory notice filed with the State Tax Commissioner.

3. Regional Transit Authorities (RTA)

Regional transit levies enacted under Ohio R.C. § 306.70 and § 5739.023:

COTA (Central Ohio Transit Authority): 1.00% in Franklin County.
WRTA (Western Reserve Transit Authority): 0.25% in Mahoning County.
Laketran: 0.50% in Lake County.

4. US Census Bureau TIGER/Line Boundary Geocoding

For street-level address resolution, coordinates and municipal polygons are matched against US Census Bureau TIGER/Line geographic shapefiles to eliminate split-county boundary ambiguities.

Statutory Rounding Standard (R.C. § 5739.025)

Ohio Revised Code § 5739.025 explicitly governs fractional cent rounding:

Half-Up Rounding Rule:
- Fractions of less than one-half cent ($0.0049 or lower) are discarded.
- Fractions of one-half cent or greater ($0.0050 or higher) round up to the next full cent ($0.01).
Aggregate Calculation Rule:
- In multi-item sales transactions, sales tax must be computed on the total taxable purchase amount, rather than rounding each item individually.

Audit-Proof Certificate & Logging

Every API lookup returns:

last_reconciled: Timestamp of state reconciliation.
source: "Ohio Department of Taxation".
statutory_sourcing: Explicit legal citation.
request_id: Immutable tracing token.

These parameters provide tax attorneys, CPAs, and corporate controllers with defensible audit documentation during statutory sales and use tax examinations.