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The equation, the inputs and the rounding rules are written on the page.
Know your numbers before you sign anything.
Free US calculators that show the formula, the assumptions and the sources on every page.
Try it: 30-year fixed mortgage
Example rateEstimated monthly payment
$2,489
Principal and interest
$2,023
Tax and insurance (estimate)
$467
Assumes 1.1% property tax and $1,200 a year in home insurance.
Open the full mortgage calculatorStart with a calculator
Pick one, change the numbers, see the math.
Home & mortgage
Mortgage calculator with taxes, insurance and PMI
See the payment your lender's ad leaves out, and the month PMI drops off.
30-year loan balance ($320,000 principal)
Open the calculator
Saving & investing
Compound interest calculator
$10,000.00 + $500.00 a month for 30 years at 7.00%
$691,150.47
73% of it is growth, not deposits.
Open the calculator
Income & taxes
Social Security COLA calculator: 2027 COLA is 3.6%
3.6% announcedOpen the calculator
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Buying a home
- Mortgage calculator with taxes, insurance and PMI Monthly payment with optional taxes, insurance and PMI, plus payoff time.
Growing money
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Getting paid
- Paycheck calculator for states with no wage income tax Take-home pay after federal income tax and FICA. Covers states with no wage income tax only.
- Salary to hourly calculator Convert an annual salary to hourly, daily, weekly and monthly pay.
- Social Security COLA calculator: 2027 COLA is 3.6% The 2027 COLA is 3.6%. See how it changes your Social Security check after Medicare Part B.
Getting out of debt
- Car loan calculator with sales tax and trade-in Monthly payment and total interest on a fixed-rate auto loan.
- Debt payoff calculator for up to three balances Time and interest to clear up to three debts, by highest rate or smallest balance first.
- Student loan calculator for the standard 10-year plan Monthly payment and total interest on a standard 10-year repayment plan.
You can check every number.
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Tested against worked examples
Every release runs automated tests against examples we checked by hand.
Reviewed when the rules change
Tax and benefit figures are updated from IRS and SSA publications when they are released.
Fixed-rate monthly payment
In words The monthly payment is the loan amount times a factor built from the monthly rate and the number of months.
11 live calculators
Free calculators
42 checked examples
Worked examples we check by hand
17 cited sources
Official sources cited
What changed recently
- Oct 16, 2026 Medicare Part B 2026 premium on the COLA calculator
COLA calculator defaults use the CMS 2026 Part B standard premium of $202.90. The 2027 premium is not announced yet.
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2026 retirement limits and Social Security wage base added
- Oct 15, 2026 Social Security 2027 COLA of 3.6 percent added
Social Security 2027 COLA of 3.6 percent added
- Oct 11, 2026 Social Security COLA calculator published
The Social Security COLA calculator is live with the official 2027 COLA of 3.6 percent.