Methodology and data sources

Every result on Calcvera comes from published rules and standard financial math. This page lists the official figures our calculators use, where they come from, and how we check them.

Last updated

How our calculators work

  • They run in your browser. The numbers you enter are never sent to our servers.
  • Every calculator shows its work. Each page explains the formula, walks through a worked example and lists its official sources.
  • Loans use standard amortization. Monthly payments apply your APR monthly (APR ÷ 12) to the remaining balance, the way installment loans are normally quoted.
  • APRs follow the federal method. For merchant cash advances, invoice factoring and equipment financing, we find the rate at which your payments exactly repay the cash you receive, then annualize it, as Regulation Z describes for consumer loans.
  • Tax estimates are federal only, using the brackets and deductions below. State income taxes, credits and other deductions aren’t included unless a page says so.

Federal income tax (2026)

Used by the Schedule 1-A, tips, overtime, car loan interest and senior deduction calculators. The 2025 figures are also built in for 2025 returns.

RateSingle: taxable incomeMarried filing jointly
10% Up to $12,400 Up to $24,800
12% $12,400 to $50,400 $24,800 to $100,800
22% $50,400 to $105,700 $100,800 to $211,400
24% $105,700 to $201,775 $211,400 to $403,550
32% $201,775 to $256,225 $403,550 to $512,450
35% $256,225 to $640,600 $512,450 to $768,700
37% Over $640,600 Over $768,700
Standard deduction20252026
Single or married filing separately$15,750$16,100
Married filing jointly$31,500$32,200
Head of household$23,625$24,150
Extra amount per person 65+ or blind (married)$1,600$1,650
Extra amount per person 65+ or blind (unmarried)$2,000$2,050

New deductions for 2025–2028

Created by the 2025 tax law (Public Law 119-21) and claimed on Schedule 1-A:

DeductionMaximumPhase-out
Qualified tips$25,000 per return−$100 per $1,000 of MAGI over $150,000 ($300,000 joint)
Qualified overtime (FLSA premium only)$12,500 ($25,000 joint)−$100 per $1,000 of MAGI over $150,000 ($300,000 joint)
Car loan interest$10,000 per return−$200 per $1,000, or part of $1,000, of MAGI over $100,000 ($200,000 joint)
Senior deduction$6,000 per person 65+−6% of MAGI over $75,000 ($150,000 joint)

Married people filing separately can’t claim the tips, overtime or senior deductions. For the tips and overtime deductions, the phase-out counts whole $1,000 steps. The car loan interest phase-out counts any part of $1,000 as a full step, as the law’s wording provides.

ACA premium tax credit (2026 coverage)

Used by the ACA subsidy calculator. Marketplace subsidies for 2026 use the 2025 federal poverty guidelines:

Region1 personEach additional person
48 contiguous states and DC $15,650 $5,500
Alaska $19,550 $6,880
Hawaii $17,990 $6,330

Your expected contribution toward the benchmark silver plan is a share of your household income that rises with income:

Household income (% of poverty line)Share of income you pay (2026)
Under 133% 2.10%
133% to 150% 3.14% to 4.19%
150% to 200% 4.19% to 6.60%
200% to 250% 6.60% to 8.44%
250% to 300% 8.44% to 9.96%
300% to 400% 9.96%
Above 400%No premium tax credit

Within each band, the percentage rises in a straight line from the lower to the higher figure. The enhanced credits of 2021–2025 expired at the end of 2025, which is why a cliff returns at 400% for 2026.

Medicare IRMAA (2026)

Used by the IRMAA calculator. The standard Part B premium for 2026 is $202.90 a month, with a $283 deductible. Higher-income beneficiaries pay more, based on their modified AGI from two years earlier (their 2024 tax return for 2026):

MAGI, individual returnMAGI, joint returnPart B premiumPart D surcharge
$109,000 or less $218,000 or less $202.90 —
Over $109,000 to $137,000 Over $218,000 to $274,000 $284.10 +$14.50
Over $137,000 to $171,000 Over $274,000 to $342,000 $405.80 +$37.50
Over $171,000 to $205,000 Over $342,000 to $410,000 $527.50 +$60.40
Over $205,000 and under $500,000 Over $410,000 and under $750,000 $649.20 +$83.30
$500,000 or more $750,000 or more $689.90 +$91.00

SSDI back pay

Used by the SSDI back pay calculator:

  • Benefits start after a five-month waiting period of full calendar months from the established onset date. There is no waiting period for ALS.
  • Benefits can be paid for up to 12 months before the month you applied.
  • A representative’s fee under a fee agreement is 25% of past-due benefits, capped at $9,200.

Lending and business calculators

The DTI calculator compares your ratios with these program limits:

ProgramFront-end (housing)Back-end (all debts)
Conventional (automated) — 50%
Conventional (manual) — 45%
FHA 31% 43%
VA (guideline) — 41%
USDA 29% 41%
Typical HELOC lender — 43%

Home equity limits, DSCR requirements, merchant cash advance factor rates and invoice factoring fees vary by lender. Our calculators let you enter the terms you’re quoted. Where pages mention typical ranges, those are industry norms, not legal limits.

How we test the math

  • Every calculation engine is covered by automated tests that run on every change to the site.
  • Tests check results against known values, such as standard amortization results and published premium tables.
  • Tests also check that official tables are internally consistent. For example, each IRMAA Part B amount must equal the standard premium times 1.4, 2.0, 2.6, 3.2 or 3.4.
  • Every build is checked automatically for broken links and missing page information before it goes live.

When we update

Agencies publish new figures on a regular calendar. We update the affected calculators when they do, and change each page’s date only when its content changes.

WhenWhat changesWhere
August–September IRS applicable percentages for next year’s ACA premium tax credits ACA subsidy calculator
October IRS tax brackets and standard deduction for the next tax year Tax deduction calculators
October Social Security cost-of-living adjustment and earnings limits SSDI back pay calculator
October–November CMS Medicare Part B premium and IRMAA brackets IRMAA calculator
January HHS poverty guidelines, used for the next ACA coverage year ACA subsidy calculator

Limitations

Our results are estimates for education. Your actual tax, premium, benefit or loan terms can depend on details our calculators don’t ask about, such as state rules, other credits and deductions, or a lender’s own requirements. Check important numbers with the agency or lender involved, or with a qualified professional.

Official sources

Corrections

If you think a figure or a result is wrong, email [email protected] with the page and the numbers you entered. We check every report against the official source, fix confirmed errors promptly and update the page’s date. Read more in our editorial policy.