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Mortgage Calculator Ohio
A 1976 law most homeowners have never heard of quietly decides how much your Ohio property tax actually moves when values rise. This calculator explains House Bill 920 before it gives you a number, not after.
Estimate your Ohio mortgage payment
Updates liveIllustrative estimate only. Ohio's effective rate reflects voted-levy reduction factors already baked into typical local rates — confirm your exact county figure. Not a loan offer or financial advice.
Diagram: Ohio's tax reduction factor only shields voted levies — a real, ongoing distinction most homeowners never learn about until their bill changes.
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Understanding the Ohio mortgage market
What makes an Ohio mortgage different
Ohio's effective property tax rate sits moderately above the national average — but the mechanism behind how that rate moves each year is truly unusual, and this mortgage calculator Ohio buyers use walks you through it before you budget for the long term.
House Bill 920, explained properly
Passed in 1976 in response to inflation-driven jumps in home values, House Bill 920 created what Ohio calls "tax reduction factors." The idea is simple even if the mechanics aren't: when a levy is approved by voters to raise a specific amount of money, HB 920 automatically reduces the effective rate on that levy as property values rise, so the levy keeps collecting roughly what voters originally approved — not more, just because home values went up.
In practice, this means a school district that asked voters for 5 mills to raise $10 million doesn't suddenly collect $20 million just because area home values doubled. The effective millage rate on that levy quietly drops instead, and the district still collects close to its original $10 million, plus whatever new construction adds to the tax base. This mortgage calculator Ohio residents use builds that quirk in rather than pretending property tax scales evenly with value.
Inside millage vs voted millage
Not everything is protected by HB 920. Ohio's Constitution allows local governments to jointly levy up to 10 "inside" mills — unvoted millage — without needing voter approval at all. This inside millage isn't subject to the HB 920 reduction factor, so it rises directly in step with property value increases, the same way property tax works in most other states. It's a real distinction most homeowners never think about until their specific bill starts moving in ways that surprise them.
| Millage type | Subject to HB 920 reduction? | How it behaves as values rise |
|---|---|---|
| Voted (outside) millage | Yes, until the 20-mill floor | Effective rate falls, keeping collections roughly stable |
| Inside (unvoted) millage | No | Rises directly with property value, capped at 10 mills |
| New levies (post-2013) | Yes for reduction factor; rollback credits limited | Subject to the same reduction mechanism, fewer legacy credits |
The 20-mill floor — where the protection runs out
Here's the part of HB 920 that's making news in fast-growing parts of Ohio right now. School districts have a "20-mill floor" — once the HB 920 reduction factor has pushed a district's effective operating rate down to 20 mills, the reduction factor can't push it any lower, even if property values keep climbing. Once a district hits that floor, further value increases start flowing through to actual tax bills again, which is exactly what's been happening in counties that recently completed reappraisals showing large value jumps.
Why Ohio assesses at 35% of value
Ohio doesn't tax a property's full appraised market value — it assesses real property at 35% of that value, and local millage rates are applied to that reduced assessed figure, not the full price. This is simply how the math works here; it doesn't mean Ohio's real tax burden is automatically lower, since millage rates are set with this 35% assessment ratio already baked into how districts calculate what they need to raise.
The 10% and 2.5% rollbacks
Eligible residential and agricultural property statewide generally receives a 10% reduction credit (the "nonbusiness credit"), and owner-occupied homes can receive an additional 2.5% owner-occupancy credit on top of that, both applied against qualifying levies. It's worth knowing these rollback credits generally don't apply to newer levies passed after 2013, so their overall impact on a specific bill depends on the mix of older and newer levies in a given taxing district.
The Homestead Exemption
Ohio's Homestead Exemption reduces the taxable value of a primary residence for eligible senior citizens, homeowners with a qualifying disability, and some surviving spouses, subject to income limits that are periodically adjusted. This exemption needs to be applied for through the county auditor's office and isn't automatically applied once you become eligible.
A worked example, start to finish. Say a buyer purchases a $255,000 home in an Ohio suburb with a combined effective tax rate of 1.6%, reflecting a mix of HB 920-protected voted levies and inside millage. With a 10% down payment, they're financing $229,500 at 6.6% over 30 years, giving a principal and interest payment of about $1,467.
Property tax adds roughly $340 a month at that 1.6% effective rate. Add a typical Ohio insurance premium of around $121 a month, and the full payment comes to about $1,845.
If the county completes a reappraisal a few years later showing a 30% jump in area home values — not unusual in some Ohio counties recently — this buyer's bill on the voted-levy portion largely stays protected by the HB 920 reduction factor, provided the relevant district hasn't hit its 20-mill floor. The inside millage portion, however, rises directly with that new higher value, which is exactly why understanding both pieces matters for long-term budgeting, not just the number at closing.
How to use this mortgage calculator Ohio tool
Enter the home price and down payment you're working with, along with your expected interest rate and loan term. The property tax field defaults to a typical statewide effective rate of 1.6% — adjust it if you know your specific county and school district's actual combined rate, which your county auditor's website can usually confirm. Add an estimated annual insurance premium, and this mortgage calculator Ohio shows your full estimated monthly payment.
Common mistakes to avoid
- Assuming property tax stays flat no matter what happens to values. Inside millage and the 20-mill floor both mean bills can still rise.
- Confusing assessed value with market value. Ohio taxes 35% of appraised value, not the full price.
- Not applying for the Homestead Exemption if eligible. It requires an application through the county auditor.
- Assuming rollback credits apply to every levy. Newer levies passed after 2013 generally don't carry the older rollback credits.
- Ignoring recent reappraisal news in your target county. A district near its 20-mill floor can see real bill increases even under HB 920.
Quick glossary
- House Bill 920 (HB 920)
- A 1976 Ohio law reducing the effective rate on voted property tax levies as values rise, to prevent automatic revenue windfalls.
- Inside millage
- Up to 10 mills of unvoted property tax that local governments can jointly levy without approval, not subject to HB 920 reduction.
- 20-mill floor
- The minimum effective operating rate for school district voted levies, below which the HB 920 reduction factor can't reduce rates further.
- Mill
- A unit equal to $1 of tax per $1,000 of assessed value.
- 35% assessment ratio
- Ohio's rule taxing real property at 35% of its appraised market value, rather than the full value.
The bottom line
Ohio's property tax system is truly more protective of homeowners than most states' — until a district hits its 20-mill floor, or until you factor in the unvoted inside millage that rises regardless. Understanding both pieces, rather than assuming a flat effective rate applies forever, is exactly what this mortgage calculator Ohio is built to help with, giving a far more realistic picture of what a long-term Ohio mortgage actually costs.
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