Calculators
Figures that run on this device. Finance, math, dates, health, and everyday pages apply a formula to the numbers you type. Output is informational, not tax, lending, medical, or investment advice.
113 tools
Categories
Finance
Start in finance calculators for investment, loans, tax, income, and business pages.
Math, dates, and everyday
Open math for scientific, percentage, statistics, and geometry. Date and time covers age, business days, and timesheets. Health is BMI, BMR, and related estimates. Everyday has tip, GPA, and pace.
Figures, not advice
These pages apply a formula to the numbers you type. They do not load live rates or a lender schedule. Confirm a decision where it actually binds you. See the disclaimer.
Calculator groups
Date and time
- Age Calculator Civil calendar age in the local timezone of this device. Leave As of blank to use today.
- Business Days Calculator Count Monday–Friday between two dates. Optional holidays you type. No public-holiday API.
- Year Calendar Leap flag, weekday of 1 January, ISO week count, and a 12-month table of lengths and start weekdays.
- Date Countdown Days remaining until a date, or days since if the target is past. Also years/months/days.
- Add or Subtract Days Add or subtract years, months, weeks, and days. Month ends clamp (31 Jan + 1 month is 28 or 29 Feb).
- Date Difference Calculator Days between two local calendar dates. If the end is before the start, the result is signed negative.
- Day of Week Calculator Weekday, ISO weekday (Monday = 1), day of year, and leap-year flag.
- Hours Minutes Seconds Calculator Convert duration parts, decimal hours, or total seconds into HH:MM:SS and the other totals.
- Time Card Calculator Time card total from in/out lines. Same engine as timesheet, labeled for time-clock searches.
- Time Duration Calculator Add two durations or subtract the second from the first. Hours may go past 24.
- Timesheet Calculator Sum clock-in/out lines into total, regular, and overtime hours. Optional unpaid minutes per line.
- Week Number Calculator ISO-8601 week number and ISO year. Weeks start Monday. Week 1 contains 4 January.
- Work Hours Calculator Net hours for a clock-in/out pair, unpaid break, optional day multiplier, and overtime over a daily threshold.
Everyday
- Download Time Calculator Time to transfer a size at a rate you type. Not a speed test.
- GPA Calculator One course per line: grade and credits, such as A 3 or 3.7 4. Default letters use a 4.0 scale. Your school may differ.
- Final Grade Calculator Score needed on remaining work, or GPA needed on new credits, to hit a target.
- Pace Calculator Running or walking pace per km and per mile, plus speed, from distance and time.
- Speed Distance Time Enter exactly two of distance, speed, and time. The third is solved. Pace is listed as well.
- Bill Split Calculator Split a bill, optional tax, and tip across N people in this browser.
- Tip Calculator Tip is bill times percent. Total is bill plus tip. Per person divides the total. Not a local tax table.
Business
- Break-Even Calculator Units to break even: fixed costs divided by contribution margin per unit.
- Straight-Line Depreciation Straight-line depreciation from cost, salvage, and useful life. Not tax-code MACRS.
- Discount Calculator Sale price after a percent off. Informational, not a store coupon.
- Profit Margin Calculator Gross margin, markup, and profit from cost and selling price.
- Markup Calculator Selling price from cost and markup percent.
Income
- Commission Calculator Commission from sales and a single percent. Optional base pay. No tier table in this version.
- Overtime Pay Calculator Regular hours plus overtime hours times a multiplier. Gross only.
- Gross Pay Calculator Gross pay from hours and rate, with optional overtime. No tax withholding tables.
- Salary to Hourly Calculator Gross pay only. Hours per week and weeks per year are yours to set. No tax withholding.
- Take-Home Pay Calculator Net from gross using a tax-and-deduction percent you type. Not a payroll tax table.
Investment
- APR to APY Calculator Convert a nominal APR and compounding frequency to APY, or the reverse. Informational, not a product APY.
- CAGR Calculator Compound annual growth rate between a start value and an end value. Informational, not a forecast.
- Cap Rate Calculator Capitalization rate = NOI / property value. Informational, not an appraisal.
- CD Interest Calculator Certificate of deposit future value at a fixed rate and term you type. Not a bank APY pull.
- Compound Interest Calculator Future value of a lump sum that compounds on a fixed schedule. Figures stay on this device. They are not a forecast or advice.
- Future Value Calculator Future value of a lump sum plus an optional payment stream at a fixed rate.
- Inflation Calculator Adjust an amount by an annual inflation rate you type. No live CPI.
- IRR Calculator Internal rate of return: the rate that makes NPV of your cash flows equal zero.
- NPV Calculator Net present value of a cash-flow list you type. Informational, not a valuation.
- Payback Period Calculator Simple payback = investment / annual cash-in. Optional discounted payback at a rate you type.
- Present Value Calculator Discount a future amount and an optional annuity at a fixed rate.
- 401(k) Projection Calculator Simple 401(k) projection from balance, contribution, optional match, years, and a fixed return. Not tax-aware.
- ROI Calculator Return on investment from cost and final value. Informational, not performance reporting.
- Rule of 72 Calculator Years to double: 72 / rate, plus the exact ln(2)/ln(1+r) comparison.
- Savings Goal Calculator Payment needed each period to reach a future amount at a fixed rate.
- Simple Interest Calculator Simple interest does not add earned interest back to the principal. Figures are informational, not investment advice.
- SIP Calculator Future value of equal periodic contributions at a fixed rate (SIP / recurring investment).
Loans
- Amortization Schedule Fixed-rate amortization table: payment, principal, interest, and balance each period. Informational, not a lender quote.
- Car Payment Calculator Auto loan payment from price, down payment, rate, and term. Informational, not a dealer quote.
- Credit Card Payoff Calculator Months to pay off a revolving balance at a fixed APR and a payment you type.
- Down Payment Calculator Down payment from price and percent, or percent from an amount you type. Optional principal-and-interest estimate.
- EMI Calculator Equated monthly installment on a reducing balance. Informational, not a bank EMI letter.
- Extra Payment Calculator See how extra principal shortens a fixed-rate loan. Informational, not a payoff quote.
- Interest-Only Loan Calculator Interest-only payment = principal times the periodic rate. Principal is due as a balloon at the end of this term.
- Loan Calculator Standard amortization of a fixed-rate loan. Informational, not lending advice.
- How Much House Can I Afford Invert PMT: maximum loan from a target payment, rate, and term. Ignores taxes, insurance, and lender rules unless you type income and DTI.
- Mortgage Calculator Principal and interest for a fixed-rate mortgage. Tax, insurance, and HOA are not included unless you fold them into the amount yourself.
Tax
Health
- BMI Calculator BMI = kg / m². US units convert with 1 lb = 0.45359237 kg and 1 in = 0.0254 m. Informational, not a medical diagnosis.
- BMR Calculator Basal metabolic rate from Mifflin-St Jeor and revised Harris-Benedict. Optional Katch-McArdle if you type body fat. Not medical advice.
- Navy Body Fat Calculator US Navy circumference method. Metric tapes are converted to inches inside the formula. Informational, not an accession tape.
- Gestational Age Calculator Gestational age from LMP, estimated due date, and trimester. Same 280-day rule as the due-date page.
- Ideal Weight Calculator Devine, Robinson, Miller, and Hamwi ideal-weight formulas, plus the WHO BMI 18.5–24.9 band for that height.
- Lean Body Mass Calculator Lean mass from a body-fat percent you type, or Boer / James / Hume estimates from height, weight, and sex.
- Due Date Calculator Estimated due date as LMP + 280 days (Naegele), with gestational age and trimester. Not obstetric care.
- TDEE Calculator TDEE = Mifflin-St Jeor BMR × activity factor. All five common factors are listed. Not a diet prescription.
Math
- Adding Machine Running total of a list: sum, count, and mean. Negatives allowed as subtractions.
- Binary Math Calculator Integer binary math and bitwise ops. Output in decimal, binary, hex, and octal. Stays in this tab.
- Combination Calculator C(n, k) = n! / (k! (n − k)!) for unordered selections.
- Decimal to Fraction Calculator Best-fit fraction for a decimal, searching denominators up to the cap you set.
- Distance Between Two Points Euclidean distance between two plane points.
- Exponent Calculator base^exponent with IEEE floating point. Rejects non-finite results.
- Factorial Calculator n! for an integer from 0 to 170. 0! is 1.
- Fraction to Decimal Calculator Divide a fraction to a decimal and show the simplified form.
- Fraction Calculator Add, subtract, multiply, or divide two fractions. Result is simplified, mixed, and decimal.
- GCD Calculator Greatest common divisor of two or more integers, Euclidean algorithm.
- Increase or Decrease by Percent Increase or decrease a number by a percent. Returns the new amount and the difference.
- LCM Calculator Least common multiple of two or more integers. Rejects results beyond safe integers.
- Logarithm Calculator log_base(value), plus ln and log10 of the same value. Value must be positive.
- Long Division Calculator Integer division with quotient, remainder, and a reconstruction check. Truncates toward zero.
- Mixed Number Calculator Convert mixed numbers to improper fractions and back, then simplify.
- Nth Root Calculator Principal real nth root. Even roots of negatives are rejected. n cannot be 0.
- Order of Operations Calculator Evaluate an arithmetic expression with ^ as power, * / before + −, and parentheses. Same parser as the scientific calculator.
- Percentage Change Calculator Percent change from an original value to a new value, plus the raw difference.
- What Is P Percent of X What is P percent of X. Same arithmetic as the percentage hub, locked to this job.
- Percentage to Fraction Convert a percent to a simplified fraction, mixed number, and decimal.
- Percentage Calculator Everyday percentage jobs: of, what percent, change, increase, and decrease. Figures stay on this device.
- Permutation Calculator P(n, k) = n! / (n − k)! for ordered selections. n at most 170 on this page.
- Prime Factorization Prime factorization of an integer from 2 to 1,000,000,000,000.
- Prime Checker Trial-division primality for integers up to 1,000,000,000,000 in absolute value.
- Proportion Calculator Solve a/b = c/d. Leave exactly one of a, b, c, d blank.
- Quadratic Formula Calculator Roots of ax² + bx + c = 0, including complex roots when the discriminant is negative.
- Ratio Calculator Simplify a:b and optionally solve a:b = c:x.
- Scientific Calculator Type an expression or use the keypad. Trigonometry uses the angle mode you pick. Nothing is uploaded.
- Slope Calculator Slope, y-intercept, line equation, and distance between two points. Vertical lines are flagged.
- Square Root Calculator Principal square root. Negatives are rejected as non-real on this page.
- What Percent Is X of Y What percent is A of B. Whole cannot be 0.
Geometry
- Circle Calculator Radius, diameter, circumference, and area. Enter any one; the rest follow with π from this device.
- Cylinder Calculator Right circular cylinder: volume, lateral area, and total surface area.
- Pythagorean Theorem Calculator Solve a² + b² = c². Enter exactly two of a, b, and c.
- Rectangle Calculator Rectangle area, perimeter, and diagonal. A square is the case length = width.
- Sphere Calculator Sphere volume and surface area from radius.
- Triangle Calculator SSS triangle: Heron area, perimeter, all three angles, side class, and acute/right/obtuse.
Statistics
- Average Calculator Arithmetic mean, sum, count, min, max, and range of a list you type.
- Median and Mode Median and mode of a numeric list. Ties for mode are listed together.
- Standard Deviation Calculator Population and sample standard deviation and variance for a list you type.
- Variance Calculator Population and sample variance, with matching standard deviations.
- Weighted Average Weighted average from value-weight pairs. Weights must sum to more than 0.
- Z-Score Calculator z = (x − mean) / SD. Standard deviation cannot be 0.
Calculator questions
Does a calculator upload my numbers?
No. The formula runs in the page you opened. CZNull does not receive the values.
Is the result a quote I can take to a bank?
No. Rounding, day counts, fees, and tax in the real world can differ. Use the page to check the arithmetic.