USUnited StatesUSD · IRSUS

Methodology

How the calculators work, where the numbers come from, and what an estimate leaves out.

Where the figures come from

Tax figures are taken from published IRS guidance and kept in data files, never written into the calculator code. When a threshold changes, one data file is updated and every page that uses it changes with it. Each figure is cited on the sourcespage, and each calculator shows when its figures were last verified.

Overtime Tax Deduction Calculator

  1. Premium per hour. Only the premium portion of overtime pay qualifies — the extra half of time-and-a-half required under section 7 of the Fair Labor Standards Act. The calculator takes half of your regular hourly rate.
  2. Qualified overtime. The premium per hour multiplied by your overtime hours for the year.
  3. Annual cap. The deduction is capped at $12,500 for single filers and heads of household and$25,000 for married couples filing jointly. Married filing separately is not eligible.
  4. Income phase-out. Above $150,000 of income ($300,000 for joint filers) the deduction is reduced by $100 for every full $1,000 over the threshold. A partial thousand is rounded down, as line 19 of Schedule 1-A instructs. It cannot go below zero.
  5. Estimated saving. The deductible amount multiplied by your marginal federal rate. That rate is looked up on taxable income — your income less the standard deduction for your filing status — using the 2026 federal brackets.

Tax Refund Calculator With Overtime

  1. Deduction. The same cap and income phase-out as the Overtime Tax Deduction Calculator, from one shared function, so the two pages always agree.
  2. Taxable income. Total income, less the standard deduction, less the overtime deduction, never below zero.
  3. Tax. Worked bracket by bracket through the 2026 tables in Rev. Proc. 2025-32, to the cent, then reduced by any credits entered. Credits cannot take the tax below zero.
  4. Refund. Federal tax withheld minus tax owed. A negative result is a balance due. The overtime deduction's effect is the refund with it minus the refund without it.

Total income is used as modified adjusted gross income for the phase-out; the IRS defines the exact measure in Notice 2025-69. The estimate is federal only and leaves out state tax, self-employment tax and refundable credits. It covers tax year 2026 only.

Mortgage Recast Calculator

  1. New balance. Your balance less the lump sum. A lump sum larger than the balance pays the loan off and there is nothing to recast.
  2. New payment. The standard monthly amortisation formula on the new balance, over the same remaining months at the same rate. All arithmetic is in whole cents, so a 360-payment schedule cannot drift.
  3. Interest saved. Total interest over the remaining term before the recast, less total interest after it.
  4. Fee payback. The recast fee divided by the monthly reduction, rounded up to whole months. Under12 months is treated as worth it — a rule of thumb, not a lender rule.
  5. Extra-payment comparison. The same lump sum paid straight to principal keeps the payment and shortens the term instead.

Fees, minimum lump sums and which loan types can be recast are planning defaults drawn from published lender guidance. They are not a legal rule and not the policy of any one servicer, so the calculator asks you to confirm them with yours.

Recast vs Refinance Calculator

  1. Recast side. The same engine as the Mortgage Recast Calculator, so the two pages always agree.
  2. Refinance side. A cash-in refinance: the same lump sum reduces the balance, and the remainder is refinanced at the new rate over the same remaining months. Closing costs are paid in cash rather than rolled into the loan. This keeps both routes on the same cash and the same term, so the comparison is like for like.
  3. Total cost. The lump sum, the fee or closing costs, and every monthly payment over the remaining term.
  4. Break-even. The extra upfront cost of the refinance divided by how much lower its payment is, rounded up to whole months. It is shown only when the refinance payment is lower.

A real refinance can also change the term, roll in cash-out or costs, or affect tax and insurance escrow, none of which is modelled. The lender comparison uses only what each lender publishes on its own website. Where a figure is not published it is marked "Not published" and is never estimated.

Texas Vehicle Tax, Title and License Calculator

  1. Taxable amount. The purchase price minus any trade-in allowance, never below zero. The engine reads how a state treats a trade-in from that state's data file, so other states can tax the full price or cap the credit.
  2. Sales tax. The taxable amount multiplied by 6.25%, rounded to the cent. This is the one exact figure in the estimate.
  3. Title and registration. These vary by county, so they are shown as ranges: a title fee of $28 or$33, a base registration fee of $50.75 for cars and light trucks, and local county fees of up to $31.50.
  4. Private-party sales. Texas taxes the greater of the price paid or 80% of the vehicle's Standard Presumptive Value. SPV values are not built in, so an estimate without one carries a warning that the real tax could be higher.

The total is shown as a range. Verify title and local fees with your county tax assessor-collector's office.

A known interpretive gap: trade-ins on private-party sales

On a private-party sale the Texas Comptroller taxes the greater of the sales price (total consideration) or 80% of the vehicle's SPV, and says SPV procedures may apply to the taxable value of the vehicle bought but not to the value of the trade-in. Neither page says whether the 80%-of-SPV comparison is made before or after a trade-in is subtracted. We compare 80% of the SPV with the price beforethe trade-in, then subtract the trade-in from the greater figure. That is our reading, not a rule the Comptroller states, so whenever a trade-in and the SPV floor both apply to the same private sale the calculator says the figure is directional and to confirm it with your county tax office. The two pages:Texas Comptroller — Trade-Ins (Motor Vehicle Tax Guide) andTexas Comptroller — Standard Presumptive Value (Motor Vehicle Tax Guide).

California Vehicle Tax, Title and License Calculator

  1. Sales tax. The full price multiplied by the statewide rate plus the district tax you enter, rounded to the cent. A trade-in does not reduce the price: CDTFA's dealer guide says the allowance cannot be excluded. Until you enter a district rate the estimate uses the state rate only and says so.
  2. Fixed DMV fees. The registration fee (which includes a $3 alternative fuel/technology fee), the CHP fee and the title fee. The title fee was last confirmed at $25 in January 2023, before DMV's yearly CPI increases, and DMV's current fees page lists $28 for a replacement title, so it is shown as a $25 to $28 range.
  3. Value-based DMV fees. The vehicle license fee is 0.65% of value, and the transportation improvement fee is a flat amount for the value band the vehicle falls in. DMV decides the value; the calculator uses your purchase price.
  4. Left out. County and district registration fees, dealer documentation fees, the road improvement fee for some zero-emission vehicles, and private-party purchases. Each is listed on the page rather than estimated.

New York Vehicle Tax, Title and License Calculator

  1. Sales tax. The taxed price multiplied by the 4% state rate plus your county's rate from Publication 718, rounded to the cent. New York works the rate out where the buyer lives, so the county you choose sets it. Until you choose one, the estimate uses the state rate only and says so.
  2. Trade-in. On a dealer sale the trade-in is subtracted from the taxed price. New York's dealer guide allows that only if the dealer intends to resell the vehicle, and it is a 2012 edition, so the page says to check current guidance.
  3. Registration. The DMV's two-year fee from its weight chart, using the weight you enter. Without a weight, the fee is shown as the range across the chart, $26.00 to $140.00.
  4. County use tax and MCTD fee. From the DMV's county chart, by county and weight, for two years. A county that is not on the chart shows no county use tax.
  5. Title and plates. $50 for the title certificate and $25 for plates, as the DMV lists them.
  6. Left out. Dealer charges such as documentation fees, and private-party purchases, where the DMV collects the sales tax.

Florida Car Sales Tax Calculator

  1. Sales tax. 6% of the taxable amount, plus your county's 2026 surtax on the first $5,000 of it, rounded to the cent. The county comes from the Department of Revenue's DR-15DSS table. Until you choose one, the estimate uses the state rate only and says so.
  2. Trade-in and the $5,000 cap. A qualifying trade-in is subtracted first, and the $5,000 surtax cap is applied to what is left. The Department of Revenue says the surtax applies to the first $5,000 of the purchase price but does not spell out how that combines with a trade-in. The difference only arises when the trade-in takes the taxable amount below $5,000, and is at most $100 (2% of $5,000).
  3. Title. $75.25 ($70 + $1 + $4.25, Fla. Stat. 319.32), plus $2.50 if you choose a mailed paper title.
  4. Registration. The annual license tax by weight band (Fla. Stat. 320.08), shown as the $14.50 to $32.50 range if no weight is entered, and the $225 initial registration fee (Fla. Stat. 320.072), included unless you switch it off.
  5. Left out. Other registration fees and service charges, which we could not verify, and dealer charges.

Reporting

From tax year 2026 employers report qualified overtime separately on W-2, box 12, codeTT. You claim the deduction on Schedule 1-A (Form 1040). It does not require you to itemise.

What an estimate leaves out

Corrections

If a figure looks wrong, please tell us. Corrections are checked against the source and published with the new verification date.