3752 free online calculators
All your calculators in one place
MyKalculators is a fast, free hub of online calculators — finance, business, health, math, conversions, dates, construction and education. Every calculation runs privately in your browser.
- Runs in your browser — nothing is uploaded
- Finance, health, math & conversion tools
- Free, fast & mobile friendly
Recently used
Most used
Popular calculators
Age Calculator Popular The Age Calculator works out exactly how old you are in years, months and days from your date of birth. You can also set an 'age at' date to find how old you were (or will be) on any other day, plus your age in total months, weeks and days. Area Calculator Popular The Area Calculator finds the area of common shapes — rectangle, square, triangle, circle, trapezoid, parallelogram, and ellipse — from their dimensions. The formulas used are: Rectangle: l×w. Square: s². Triangle: ½bh. Circle: πr². Trapezoid: ½(a+b)h. Parallelogram: bh. Ellipse: πab. Average Calculator Popular Find the mean, median, mode and range of a list of numbers at once. Enter your values separated by commas or spaces and the calculator returns the mean (arithmetic average), the median (middle value), the mode (most frequent value), the range (max − min), plus the count and sum. It's a quick way to summarise a data set. BMI Calculator Popular Calculate your Body Mass Index (BMI) from your height and weight and see which category it falls into. Enter your weight and height and this calculator returns your BMI, its category, and the healthy weight range for your height. Body Fat Calculator Popular Estimate your body fat percentage with the US Navy circumference method. Enter your sex, height, and a few tape measurements to see your body fat percentage, category, and healthy range. Bricks Calculator Popular Estimate how many standard bricks you need for a wall from its length, height, and thickness. The calculator uses the common figure of about 13.5 bricks per cubic foot (for a 9×4.5×3 inch brick with mortar) and adds a 5% wastage allowance. Calories Burned Running Calculator Popular Estimate how many calories you burn running. Enter your body weight, running speed, and how long you ran, and this calculator returns the calories burned and your burn rate per minute using MET values. Calories Burned Walking Calculator Popular Estimate how many calories you burn walking. Enter your body weight, walking speed, and how long you walked, and this calculator returns the calories burned and your burn rate per minute using MET values.
Allele Frequency Calculator Allele Frequency Calculator is a biology calculator that helps you calculate allele frequency values from your input data. The formula used is: f = c/λ. Uses standard biological units (e.g. g, mg, mmol/L) unless otherwise labelled. Animal Mortality Rate Calculator Animal Mortality Rate Calculator is a biology calculator that helps you calculate animal mortality rate values from your input data. The formula used is: (Part ÷ Whole) × 100. Uses standard biological units (e.g. g, mg, mmol/L) unless otherwise labelled. Annealing Temperature Calculator The Annealing Temperature Calculator estimates the PCR annealing temperature from your primers' melting temperatures (Tm). It takes the lower of the two primer Tm values and subtracts an offset, then suggests a gradient range to optimise. The formula used is: annealing temp ≈ min(Tm_forward, Tm_reverse) − offset.
Activation Energy Calculator The activation energy is the minimum energy a reaction needs to proceed. This calculator uses the two-temperature form of the Arrhenius equation: give it the rate constants at two temperatures and it solves for the activation energy (Ea). Enter k₁ at T₁ and k₂ at T₂ (temperatures in Kelvin) and it returns Ea in both kJ/mol and J/mol. Activity Coefficient Calculator The Activity Coefficient Calculator estimates the activity coefficient (γ) of an ion in solution using the Debye-Hückel limiting-law form. It corrects for how electrostatic interactions in an electrolyte make an ion's effective (active) concentration differ from its actual concentration. Enter the ionic strength and the ion's charge to get γ. Actual Yield Calculator The Actual Yield Calculator finds the real mass of product you obtained from a reaction by combining the theoretical yield with the percent yield. Actual yield = theoretical yield × (percent yield ÷ 100). It also shows the shortfall — how much product was lost to side reactions, incomplete conversion, or handling.
AC Tonnage Calculator The AC Tonnage Calculator estimates the cooling capacity an air conditioner needs for a space, in tons. It multiplies the floor area by an assumed cooling load per square foot and divides by 12,000 BTU/hr (one ton of cooling). Use it as a quick sizing guide before a full Manual J load calculation. Air Changes Per Hour (ACH) Calculator The Air Changes Per Hour (ACH) Calculator tells you how many times the entire volume of air in a room is replaced each hour by your ventilation. It uses the airflow rate and the room volume: ACH = (airflow in CFM × 60) ÷ room volume in cubic feet. Air Conditioner BTU Calculator The Air Conditioner BTU Calculator estimates the cooling capacity (in BTU/hr) needed to cool a room, based on its dimensions, climate, sun exposure and number of occupants. It also converts the result into tonnes of cooling and kilowatts.
Acreage Calculator This acreage calculator converts an area in square feet into acres. Since one acre is exactly 43,560 square feet, it divides your square footage by 43,560. Enter the area of a plot or piece of land in square feet to see how many acres it covers — useful for real estate, farming and property listings. Acres to Hectares Converter This converter changes acres into hectares, the metric unit of land area. One acre equals about 0.404686 hectares, so the calculator multiplies your acreage by that factor. Enter an area in acres to get the equivalent in hectares — useful for farming, forestry and international land deals. Acres to Hectares Converter This Acres to Hectares Converter lets you convert Acres (acre) into Hectares (ha) in one step. Enter a value in acres and you'll instantly see the equivalent in hectares, worked out with the formula hectares = acres x 0.40468564224. It's handy whenever you need a quick, precise acres-to-hectares conversion without doing the arithmetic by hand.
AI Water Footprint Calculator The AI Water Footprint Calculator estimates how much fresh water is consumed to run your AI chatbot usage. Data centres use water to cool the servers behind each query, so total water = number of AI prompts × water used per prompt. Benzo[a]pyrene Toxic Equivalent Calculator Convert the measured concentration of a polycyclic aromatic hydrocarbon (PAH) into its benzo[a]pyrene toxic equivalent (BaP-TEQ) using a toxic equivalency factor (TEF). Benzo[a]pyrene is the reference carcinogen with a TEF of 1, and other PAHs are scaled relative to it. Enter the concentration and the TEF to get the equivalent benzo[a]pyrene dose. Books vs Ebooks Cost Calculator Compare the yearly cost of reading printed books versus ebooks. Enter how many books you read a year and the typical price of each format, plus the upfront cost of an e-reader, to see which option is cheaper and when the e-reader pays for itself.
100 Day Calculator The 100 Day Calculator helps you spread a total amount evenly across 100 days so you can see the daily average. Enter the total you plan to spend, save, produce, or consume over 100 days, and the calculator divides it by 100 to show how much that works out to per day - handy for budgeting, savings goals, habit tracking, or any plan measured over a 100-day window. 12 Hour Shift End Time Calculator This calculator tells you when a 12-hour shift ends. Enter your start time and any unpaid break, and it adds 12 hours plus the break to give the clock time you clock off. It is handy for nurses, factory and warehouse staff, security and anyone working long rotating shifts who needs to know their finish time at a glance. 120 Day Calculator The 120 Day Calculator helps you spread a total amount evenly across 120 days so you can see the daily average. Enter the total you plan to spend, save, produce, or consume over 120 days, and the calculator divides it by 120 to show how much that works out to per day - handy for budgeting, savings goals, habit tracking, or any plan measured over a 120-day window.
10/1 ARM Mortgage Calculator A 10/1 ARM is an adjustable-rate mortgage with a fixed interest rate for the first 10 years that then adjusts once a year. This calculator estimates your monthly principal-and-interest payment during the fixed period and what it could become after the first adjustment, so you can see how much your payment might rise. Enter the loan amount, the initial and expected adjusted rates, and the term. 28/36 Rule Calculator This 28/36 rule calculator shows how much you can afford to spend on housing and total debt based on your income, a guideline lenders use to assess mortgage applications. Enter your monthly income and existing monthly debt payments, and it returns the 28% housing limit, the 36% total-debt limit, and how much is left for a housing payment after your other debts. 3D Printer: Buy vs Outsource Calculator Deciding whether to buy a 3D printer or pay a service to print your parts comes down to volume. This calculator compares the total cost of owning a printer — its upfront price plus a per-part material cost — against outsourcing every part at a higher per-unit price. It shows the total each way, your saving from buying, and the break-even quantity where buying starts to pay off.
Alcohol By Volume (ABV) Calculator The Alcohol By Volume (ABV) Calculator estimates the alcohol content of beer, wine or cider from the original gravity (before fermentation) and final gravity (after fermentation). ABV = (OG − FG) × 131.25. Alcohol Dilution Calculator The Alcohol Dilution Calculator tells you how much of a strong spirit and how much water to mix to reach a target alcohol strength. It uses the dilution rule C₁V₁ = C₂V₂, so original volume = (desired % × final volume) ÷ original %. Bacon Curing Calculator Calculate the amount of curing salt (Prague Powder #1) and kosher salt needed to cure bacon using the equilibrium curing method.
2020 Vision Calculator 20/20 vision is shorthand for normal sharpness of sight: you can read at 20 feet what a person with healthy eyes reads at 20 feet. This calculator converts a Snellen test result into the familiar 20/x notation. Enter the distance you were tested at and the distance a normal eye could read the same line from, and it returns your vision ratio. A larger second number means weaker distance vision. 4Ts Score Calculator (HIT) The 4Ts score estimates how likely a drop in platelets is caused by heparin-induced thrombocytopenia (HIT). It scores four features — the degree of Thrombocytopenia, the Timing of the platelet fall, the presence of Thrombosis, and whether oTher causes are present — from 0 to 2 each, for a total of 0 to 8. The total places a patient in a low, intermediate or high pre-test probability of HIT. 5/3/1 Program Calculator 5/3/1 Program Calculator is a health and wellness calculator that helps you calculate 5/3/1 program values from your input data. The formula used is: Wk1: 65/75/85% × TM. Wk2: 70/80/90% × TM. Wk3: 75/85/95% × TM. Wk4: 40/50/60% × TM.. Enter values using the units shown next to each input field (e.g. kg, cm, years).
2×2 & 3×3 Matrix Determinant 2×2 & 3×3 Matrix Determinant is a mathematics calculator that helps you calculate 2×2 & 3×3 matrix determinant values from your input data. The formula used is: 2×2: det = ad−bc · 3×3: det = a(ei−fh)−b(di−fg)+c(dh−eg). Ensure all inputs share the same unit system (e.g. all metres or all feet) unless the formula converts between units. 2×2 Matrix Determinant Calculate the determinant of a 2×2 matrix. 2×2 Matrix Multiplication 2×2 Matrix Multiplication is a fast, free math calculator. Enter A[1,1], A[1,2] and A[2,1] to get an instant, accurate result — complete with the formula, a step-by-step worked example, and answers to common questions, all on one page and private to your browser.
0-60 Acceleration Calculator The 0-60 calculator works out the average acceleration of a vehicle that goes from a standstill to a chosen speed in a given time. Enter the 0-60 time (in seconds) and the speed reached (in mph) and you get the average acceleration in metres per second squared. It is handy for comparing the launch performance of cars or for physics homework on uniform acceleration. Angular Velocity Calculator The Angular Velocity Calculator converts a rotational speed in RPM into angular velocity, then uses the radius to find tangential speed and centripetal acceleration. The formula used is: ω = RPM × 2π/60; v = ω × r; a_c = ω² × r. Compression Ratio Calculator The Compression Ratio Calculator finds an engine's compression ratio from the cylinder (swept) volume and the clearance (combustion chamber) volume.
Air Force PT Test Score Calculator The Air Force PT Test Score Calculator adds up the points you earned in each component of the USAF physical fitness assessment — cardio (1.5-mile run or HAMR shuttle), upper body (push-ups) and core (sit-ups or plank) — to give your composite score and pass/fail result. Passing requires at least 75.0 points overall. Batting Average Calculator Work out a batting average for cricket or baseball. In cricket the average is the runs scored divided by the number of times dismissed (innings minus not-outs); in baseball it's hits divided by at-bats. Enter your figures to see both averages side by side. Bike Cadence & Speed Calculator Work out your cycling speed from your pedalling cadence (RPM), gearing, and wheel size. The calculator finds your gear ratio, wheel circumference, and how far you travel per pedal stroke, then combines them with your cadence to give speed in km/h and mph. Handy for choosing gears and pacing on the road or trainer.
Frequency Distribution Calculator Count occurrences of each unique value in a dataset and create a frequency distribution. Enter comma-separated data values to get frequencies, relative frequencies (%), and cumulative frequencies. Histogram Bin Width Calculator Calculate optimal histogram bin width using Sturges' rule or Scott's rule. Mean Calculator The Mean Calculator finds the arithmetic mean (average) of a list of numbers, along with the sum and count. Enter your values separated by commas.
Bounce Rate Calculator Calculate the bounce rate of a website or landing page — the share of visits that leave after viewing just one page without interacting. Enter the number of single-page (bounced) sessions and the total sessions to get the bounce rate as a percentage. Bradford Factor Calculator Calculate the Bradford Factor, an HR metric that weights frequent short absences more heavily than occasional long ones. Enter the number of separate absence spells and the total days absent to get the score. Burndown Chart Calculator Track an agile sprint by comparing the ideal burndown line with your actual remaining work. Enter total sprint work, sprint length, the current day, and remaining work to see whether the team is ahead of or behind schedule.
Calculators for everyday decisions
MyKalculators is a free collection of online calculators for finance, health, math, conversions, dates, construction and education. Get instant, accurate answers — each with the formula, a worked example and answers to common questions, all on one page. Regional tools (local taxes, currency and land units) are included for users who need them.
Every calculator runs entirely in your browser. Your numbers never leave your device, results update instantly as you type, and the whole site works on mobile data. Calculators that rely on tax rates or government fees show when they were last reviewed and link to the official sources, so you can always verify the figures before you rely on them.
Browse all calculators or see the data sources we use.