Finance
Calculate the true Annual Percentage Rate (APR) of a loan when upfront fees are involved. The nominal interest rate sets the monthly payment, but fees reduce the net cash received, raising the effective APR. Uses Newton's method to solve the annuity present-value equation. Shows APR, nominal rate, monthly payment, and the APR premium.
apr-calculatorMedia
Compare integrated LUFS, true peak, LRA, stereo/mono, bitrate and sample rate against Apple Podcasts, Spotify, YouTube, ACX and broadcast targets.
audio-podcast-loudness-compliance-reportMedia
Apply a configurable podcast mastering chain: high-pass, denoise, de-ess, compression, EQ tilt, LUFS normalization, and true-peak limiting.
audio-podcast-mastering-chainFinance
Convert an amount between currencies using live exchange rates from a free, no-key API (open.er-api.com). Supports 160+ world currencies. Shows the converted amount, the exchange rate used, a comparison table against popular currencies, and the rate update timestamp.
currency-exchangeFinance
Convert between hourly, monthly, and annual salary. Enter any one figure and get the other two, with customizable hours per week, weeks per year, and overtime multiplier. Shows paycheck estimates for weekly, biweekly, semimonthly, and monthly pay periods.
salary-converterFinance
Project investment growth with initial principal plus monthly contributions and compound interest. Supports compounding frequency, inflation-adjusted real value, and yearly contribution escalation, with a yearly breakdown table and nominal vs real balance curves.
investment-calculatorFinance
Discount a future lump sum or an annuity back to today's value (PV). Supports lump-sum and annuity cash flows, multiple compounding frequencies, a present-value decay curve, and a per-period breakdown. PV = FV / (1+r)^n for a lump sum.
present-value-calculatorFinance
Two-phase retirement model: an accumulation phase (current age to retirement, with monthly contributions and compound growth) and a withdrawal phase (retirement to life expectancy, nest egg grows at a conservative rate while inflation-adjusted withdrawals are taken out). Reports whether the nest egg lasts, real purchasing power, and any shortfall.
retirement-calculatorFinance
Solve for the monthly contribution needed to reach a savings goal (with interest and compounding), or for the time required to reach the goal with a fixed monthly deposit. Optional inflation adjustment. Uses monthly compounding rollup.
savings-calculatorMedia
Reduce broadband noise with a spectral filter chain
spectral-denoiserMedia
Convert up to 20 uploaded images, or images inside a ZIP archive, into WebP files packaged as a ZIP
image-to-webp-batch-converterUtilities
Estimate how many buckets of interior paint you need from room dimensions, doors/windows, coats, paint coverage, and bucket size — rounded up to whole buckets, with optional primer and waste factor.
interior-paint-coverage-estimator