Fast, free calculators for everyday decisions

Every NumKits tool runs instantly in your browser — no signup, no ads chasing you around, and nothing you type ever leaves your device.

Finance Calculators

Project savings growth with compound interest and optional monthly contributions.

Project your retirement savings and estimate the monthly income they could provide.

Solve for future value, present value, monthly payment, or time to reach a goal.

Find the exact monthly saving needed to reach a target amount by a deadline.

Find your monthly payment, total interest, and yearly amortization schedule.

Estimate your full monthly mortgage payment including taxes, insurance, and HOA.

Find your debt-free date and total interest, or the payment needed to hit a deadline.

See how inflation raises future prices and erodes the buying power of your money.

Measure return on investment: net gain, ROI %, and annualized return per year.

Split monthly after-tax income into needs, wants, and savings with the 50/30/20 rule.

Turn an annual salary into hourly, daily, weekly, and monthly pay.

Find X% of a number, what percent X is of Y, or the percentage change between two values.

Find the sale price after percent-off discounts, with stacking and optional sales tax.

Add sales tax to a price, or back out the pre-tax price from a total.

Find your body mass index from weight and height, in metric or imperial units.

Your exact age in years, months, and days from any date of birth.

Count the days between two dates, with weeks and a years/months/days breakdown.

Work out the tip, total, and each person’s share when splitting a bill.

Convert length, weight and temperature units: cm to inches, kg to lbs, °C to °F.

Live word, character, sentence, and paragraph counts with estimated reading time.