Free Online Calculators
Everyday calculators for school, work, money and health: age, percentage, GPA and CGPA, loan instalments (EMI), Zakat, BMI, discounts, profit, dates and more.
Each one explains the result, and works on your phone without an app.
- A/B Test Sample Size PlannerHow many visitors does each version need before you can trust the result? Enter your current conversion rate and the smallest lift you care about.In browser
- A/B Test Significance CalculatorDid version B really beat version A? Enter visitors and conversions to get the lift, the p-value and a plain-English verdict.In browser
- Ad & Marketing Metrics Calculator (ROAS, CPA, CTRโฆ)Enter what you spent and what you got. Calculates CTR, CPC, CPM, conversion rate, cost per sale, ROAS, ROI and break-even ROAS. Leave blank what you do not know.In browser
- Add / Subtract Time from a DateFind the date that is N days, weeks, months or years away.In browser
- Age CalculatorExact age in years, months and days, plus days until the next birthday.In browser
- BMI CalculatorBody mass index with the WHO adult category.In browser
- Body Fat Calculator (US Navy method)Estimate body fat percentage from height, neck, waist (and hips for women) with a tape measure, and see the usual category.In browser
- Break-Even CalculatorHow many units you must sell to cover fixed costs, and the sales needed for a target profit.In browser
- Co-founder Equity Split CalculatorSuggest a fair split between co-founders. Score each person from 0 to 10 on idea, full-time commitment, cash, expertise and leadership, and set how much each factor matters.In browser
- Compound Interest CalculatorSee how savings grow with compound interest.In browser
- Credit Card Payoff CalculatorHow many months it takes to clear a credit card or other debt, the total interest, and the monthly payment needed to be debt-free by a date.In browser
- Daily Calorie Needs (BMR & TDEE)Estimate maintenance, weight-loss and weight-gain calories with the MifflinโSt Jeor formula.In browser
- Date DifferenceDays, weeks, months and years between two dates.In browser
- Date InformationWeekday, day of the year, week number and leap-year check for any date.In browser
- Discount & Sales Tax CalculatorFinal price after a discount and tax.In browser
- Electricity Cost Calculator (appliances)Work out how many units (kWh) your appliances use per day and month and what they cost, at your own price per unit.In browser
- Final Grade Calculator (what do I need on the final?)Find the score you need on the final exam to reach the course grade you want, from your current grade and the finalโs weight.In browser
- Fraction CalculatorAdd, subtract, multiply and divide fractions and mixed numbers (like 1 1/2 + 3/4 ร 2/5) with brackets, and get the simplest form, mixed number and decimal.In browser
- Freelance Hourly Rate CalculatorWork out what to charge: from the income you want, your costs, tax, holidays and the hours you can really bill. Gives hourly, daily, monthly and project prices.In browser
- Fuel Cost CalculatorTrip fuel and cost from distance, mileage and fuel price.In browser
- Funding Round & Dilution CalculatorSee how much of your company you keep after raising money: post-money value, investor share, new option pool and your new percentage.In browser
- GCD (HCF) & LCM CalculatorHighest common factor and lowest common multiple.In browser
- GPA / CGPA CalculatorWork out your GPA from grades and credit hours.In browser
- Ideal Weight CalculatorIdeal body weight for your height from four well-known formulas (Robinson, Miller, Devine, Hamwi) and the healthy BMI weight range.In browser
- Loan / EMI CalculatorMonthly instalment, total interest and total repayment.In browser
- Loan Amortization ScheduleMonth-by-month table of a loan or mortgage: payment, interest, principal and balance, with optional extra payments to see how much you save.In browser
- Matrix CalculatorAdd, subtract and multiply matrices; find the transpose, determinant, inverse and rank. Rows are separated by new lines or semicolons.In browser
- Mortgage Calculator (monthly payment)Monthly home loan payment with principal and interest, property tax, insurance and HOA fees, total interest and the payoff date.In browser
- Percentage CalculatorWhat is X% of Y, X is what % of Y, and percentage change.In browser
- Pregnancy Due Date CalculatorEstimate the due date from the first day of the last period, the conception date or an IVF transfer date, with how many weeks along and the key dates.In browser
- Profit Margin & MarkupMargin, markup and the price needed for a target margin.In browser
- Programmer Calculator (bitwise)AND, OR, XOR, NOT, shifts and rotates on 8/16/32/64-bit numbers. Shows decimal, signed, hex, binary and octal.In browser
- Quadratic Equation SolverSolve axยฒ + bx + c = 0 with the quadratic formula: real or complex roots, the discriminant and the vertex, step by step.In browser
- ROI Calculator (return on investment)Profit, return on investment in percent and the yearly (annualised) return of an investment, a campaign or a project.In browser
- Running Pace CalculatorPace per kilometre and per mile, speed, and predicted times for 5K, 10K, half marathon and marathon from one run.In browser
- SaaS & Subscription Metrics (MRR, LTV, CAC payback)For subscription businesses: MRR, ARR, customer lifetime, LTV, LTV:CAC ratio and how many months to earn back the cost of winning a customer.In browser
- Salary to Hourly Wage Calculator (and back)Turn a yearly or monthly salary into an hourly, daily and weekly rate, or an hourly wage into a yearly salary.In browser
- Savings Goal PlannerHow much to save every month to reach a target, with a yearly return.In browser
- Scientific CalculatorType a calculation: + โ ร รท % ^, brackets, sqrt(), sin(), ln(), pi and more.In browser
- Sleep Calculator (bedtime & wake-up time)Find the best time to go to bed for a wake-up time, or when to wake up if you go to bed now, using 90-minute sleep cycles.In browser
- Survey Sample Size CalculatorHow many people must answer your survey? Enter your population, confidence level and margin of error.In browser
- Time Card Calculator (hours worked)Add up the hours worked in a week from start and end times with breaks, including night shifts, overtime and pay.In browser
- Tip CalculatorSplit a bill with tip between any number of people.In browser
- VAT & Sales Tax Calculator (add or remove)Add VAT, GST or sales tax to a price, or take it out of a price that already includes it. Common country rates included.In browser
- Water Intake CalculatorA simple daily drinking-water guide from your weight, exercise and climate, in litres, cups and glasses.In browser
- Working Days CalculatorCount business days between two dates, with your weekend pattern and holidays.In browser
- Zakat CalculatorEstimate zakat (2.5%) on cash, gold, silver and business assets.In browser
Questions
Is there a calculator for marks percentage?
Yes: the Percentage Calculator, and the Aggregate Calculator for admissions.
Can I use them offline?
Yes. Install Kitwise as an app and prepare it for offline use.