Calculators

Enter a weight and the reps you got with it to estimate your one-rep max, plus a training percentage chart.

Work out the profit or loss on a call or put option at expiration, bought or sold, with the breakeven price and the maximum profit and loss. Free, in your browser, no sign-up.

Find outliers with the 1.5 × IQR rule. Free, instant, in your browser.

Weekly pay with time and a half. Free, instant, in your browser.

Estimate your fertile window, ovulation day, and next period from your last period and cycle length. Free, in your browser, nothing is uploaded.

Enter a distance and finish time to get your pace, plus what it projects for common race distances.

Enter a room's dimensions to get the wall area and how many gallons of paint you need.

Equivalent resistance of 2 to 4 resistors. Free, instant, in your browser.

Generate Pascal's triangle with a chosen number of rows. Free, in your browser, no sign-up.

Estimate take-home pay from gross pay, tax withholding, and other deductions. Free, in your browser, no sign-up.

Work out the monthly payment on any loan from the amount, rate and term, or flip it and see how long a fixed monthly payment takes to clear the loan. Free, in your browser, no sign-up.

See the PayPal fee on a payment and how much you actually receive. Free, in your browser, no sign-up.

Project your pension pot at retirement from your contributions, your employer’s, and investment growth, and the income it could pay. Free, in your browser, no sign-up.

Percentage drop between two values. Free, instant, in your browser.

Convert a percentage to a decimal, and to a fraction.

Convert a percentage to a fraction in lowest terms, with steps.

Find the percentage increase or decrease between two numbers. Free, in your browser, no sign-up.

Find the symmetric percentage difference between two values. Free, in your browser, no sign-up.

Find the percentage increase from an original value to a new value. Free, in your browser, no sign-up.

Any percentile of a list, and percentile rank. Free, instant, in your browser.

Predict your next period, ovulation day and fertile window.

Interactive periodic table of all 118 elements. Free, in your browser.

Generate the first N digits of pi, e, or the golden ratio with an arbitrary-precision algorithm. Free, in your browser, nothing is uploaded.

Pool salt to reach a target ppm. Free, instant, in your browser.