The calculation you need, found and done in seconds

Estimate take-home pay for 2026: federal income tax from the IRS 2026 brackets and standard deduction, Social Security, Medicare, pre-tax 401(k) and HSA deductions, plus a state income tax rate you enter.

Add sales tax to a price or work back to the pre-tax price from a receipt total. You enter your combined state and local rate, so it works for any state, county or city.

Monthly principal and interest for a fixed-rate mortgage, plus your own estimates for property tax, homeowners insurance, PMI and HOA dues, with a yearly amortization table.

Work out what gold is worth in USD from the live international spot price: 24K, 22K, 18K and 14K, per gram, kilogram or troy ounce, with dealer premium, fees, making charge and sales tax as separate lines.

Work out what gold is worth in USD from the live international spot price: 24K, 22K, 18K and 14K, per gram, kilogram or troy ounce, with dealer premium, fees, making charge and sales tax as separate lines.

Convert between 31 major currencies, including USD, at the daily reference rate. The source, publication date and any delay are shown, and you can type your own rate if the lookup fails.

See how an initial investment plus monthly contributions grows with monthly or yearly compounding, year by year, and how long it takes to double (rule of 72).

Monthly principal and interest for a fixed-rate mortgage, plus your own estimates for property tax, homeowners insurance, PMI and HOA dues, with a yearly amortization table.

Add sales tax to a price or work back to the pre-tax price from a receipt total. You enter your combined state and local rate, so it works for any state, county or city.

Estimate take-home pay for 2026: federal income tax from the IRS 2026 brackets and standard deduction, Social Security, Medicare, pre-tax 401(k) and HSA deductions, plus a state income tax rate you enter.

Count the days, weeks, months and years between two dates, or add or subtract days, weeks, months or years from a date.

Work out the tip at any percentage and split the bill evenly between friends, with an option to round each share up to the next dollar.

Calculate your body mass index from height and weight in metric or imperial units and see your WHO weight category and the weight range for a BMI of 18.5–24.9.

Find X% of a number, what percentage one number is of another, the percentage change between two values, and a value increased or decreased by a percentage.

Convert length, area, weight, volume, temperature, speed and data units, and see the value in every unit of the same kind in one table.

Encode text to Base64 or decode Base64 back to text (UTF-8), with URL-safe and 76-character line options. Runs entirely in your browser.

Percent-encode text for URLs or decode it back, as a single value (encodeURIComponent) or a whole address (encodeURI), with an option for + as space. Query parameters are listed when decoding.

Generate up to 100 random version 4 UUIDs in your browser, in upper or lower case, with or without hyphens or braces, and check whether a value is a valid UUID.

Pretty-print, minify or validate JSON in your browser. Errors are shown with the exact line and column, and you can sort keys and choose the indentation.