45 Calculators • Formula on Every Page • Reviewed September 2026

Everyday Calculators & Practical Decision Tools

Free calculators for dates and time, home and garden projects, money and business, vehicles and energy, school and pets, plus handy online tools. 45 tools that show the formula they use, run in your browser and need no signup.

Planning a project? Start with the square footage calculator, then work out paint, tile or concrete.

Inputs stay in your browserCalculations run on your device
Formulas shownThe method is explained on each page
Worked examplesChecked by hand against the tool
Print & embed readyFree embeds for sites and blogs

Most-Used Everyday Calculators

Three tools people reach for most, with a worked example of each.

Time & dates

Age Calculator

Exact age in years, months and days, with total days lived and your next birthday.

Born 14 May 1995, on 5 Feb 2025
29 y 8 m 22 d
Total days lived
10,860
Next birthday
in 98 days
Also: Date Calculator · Pet Age
Open Age Calculator
Home & DIY

Square Footage Calculator

Room, triangle and circle area, with a waste margin and multi-room totals.

20 × 20 ft garage
400 sq ft
With 10% waste
440 sq ft
In square yards
44.4
Also: Paint · Tile · Concrete
Open Square Footage Calculator
Energy & cost

Electricity Cost Calculator

What an appliance costs to run per hour, day, month and year.

450 W PC, 6 h a day
2.7 kWh/day
30 days at 16.5¢ per kWh
$13.37
Per year
$160.38
Also: Gas Mileage · Commute Cost
Open Electricity Cost Calculator

All Everyday Calculators

45 calculators grouped by what you are trying to do. Each tag shows the formula or method the calculator uses.

Time, Date & Motion

8 tools
Y · M · DExact age
Age CalculatorExact age in years, months and days on any date, with total days lived, next birthday and milestone days such as your 10,000th day.Open calculator
end − startDays between dates
Date CalculatorDays between two dates, add or subtract days, and count business days skipping weekends, US, UK, Canada or Australia holidays.Open calculator
out − in − mealWork hours
Hours CalculatorTimecard hours with unpaid meals and overnight shifts, overtime rules, punch rounding, gross pay and a take-home estimate.Open calculator
h : mTime arithmetic
Time CalculatorTime between two clocks (overnight too), add or subtract time, and total a list of durations.Open calculator
UTC ± offsetTime zones
UTC Time ConverterConvert any time to UTC, Zulu, ISO 8601 and Unix time, and see 16 world cities with daylight saving.Open calculator
distance ÷ speedFlights
Flight Time CalculatorFlight time, distance, local arrival and jet lag between 40 major airports, with wind.Open calculator
90-minute cyclesSleep
Sleep CalculatorBedtimes and wake times that line up with 90-minute sleep cycles, plus nap lengths.Open calculator
v = d ÷ tSpeed
Speed CalculatorSpeed, running pace, travel time or distance, with split times for common races.Open calculator

Home, Garden & DIY

7 tools
L × W × T ÷ 27Concrete
Concrete CalculatorCubic yards and 80, 60 and 50 lb bags for slabs, footings, columns and steps, with waste, weight and cost.Open calculator
L × W × DGravel
Gravel CalculatorCubic yards, tons and 50 lb bags of gravel, crushed stone or granite with a compaction allowance and a bulk versus bag cost check.Open calculator
area × depth ÷ 27Mulch and soil
Mulch CalculatorMulch, compost or topsoil for beds: cubic yards, bags, weight and a bulk versus bagged cost check.Open calculator
net wall area ÷ spreadPaint
Paint CalculatorGallons and quarts for walls, ceiling and trim after doors and windows, with coats, texture and waste.Open calculator
area ÷ tile + jointTile
Tile CalculatorTiles and boxes with layout waste, plus grout weight, thin-set bags and cost.Open calculator
L × WArea
Square Footage CalculatorArea of rooms, triangles and circles in feet, inches or metres, with waste margin and a multi-room ledger.Open calculator
T × W × L ÷ 12Board feet
Lumber Board Feet CalculatorBoard feet, linear feet, volume and cost for hardwood and softwood, with a multi-board cut list.Open calculator

Money, Business & Shopping

8 tools
fixed ÷ contributionBreak-even
Break-Even CalculatorUnits and revenue to break even or hit a profit target, with margin of safety and operating leverage.Open calculator
margin ÷ (1 − margin)Pricing
Markup & Margin CalculatorConvert between markup and gross margin, and find the selling price, cost and profit.Open calculator
price ÷ quantityGroceries
Unit Price CalculatorCompare up to six products by price per unit across weight, volume or count, with a shrinkflation check.Open calculator
bill × tip %Tipping
Tip CalculatorTip, sales tax and total, split equally or by weight in exact cents.Open calculator
max(actual, dimensional)Shipping
Shipping Cost CalculatorDimensional and billable weight, zone by distance and cost at your own carrier rates, with box-size savings.Open calculator
amount × rate × daysInvoices
Invoice Late Fee CalculatorInterest and late fee on an overdue invoice, with grace period and simple or compound interest.Open calculator
budget × shareWedding
Wedding Budget CalculatorSplit a wedding budget across categories, hold back a contingency and plan vendor payments.Open calculator
labor + truck + fuelMoving
Moving Cost EstimatorCompare full-service movers, a moving container and a rental truck by distance, weight, season and services, using editable planning rates.Open calculator

Energy, Vehicles & Travel

6 tools
W × h ÷ 1000 × rateEnergy
Electricity Cost CalculatorRunning cost of any appliance per hour, day, month and year, with kWh, CO₂ and an appliance ledger.Open calculator
miles ÷ mpg × priceTrip fuel
Fuel Cost CalculatorTrip fuel cost from distance, fuel efficiency and price per gallon.Open calculator
miles ÷ gallonsFuel economy
Gas Mileage (MPG) CalculatorMPG from a fill-up or trip fuel cost, with L/100 km, passenger split, CO₂ and an EV comparison.Open calculator
2 × miles × daysCommuting
Commute Cost CalculatorMonthly and yearly cost of driving to work, with transit, rideshare and remote-work comparisons.Open calculator
value × (1 − rate)Ownership
Car Depreciation CalculatorResale value by year and total cost of ownership including loan interest, insurance, maintenance and fuel.Open calculator
gallons × CO₂Emissions
Driving Carbon Footprint CalculatorCO₂ from gasoline, diesel, hybrid or electric driving, with tree and offset equivalents.Open calculator

Personal, School & Pets

8 tools
Σ(points × credits) ÷ Σ creditsGPA
GPA CalculatorSemester and cumulative GPA on 4.0, 4.33 and 5.0 weighted scales, with prior credits.Open calculator
(target − current × (1 − w)) ÷ wGrades
Final Grade CalculatorThe score needed on a final exam to reach a target grade, in percent and points.Open calculator
16 · ln(age) + 31Pets
Pet Age CalculatorDog and cat age in human years using size-based tables or the epigenetic clock, with life stage.Open calculator
70 × kg^0.75Dog food
Dog Food Portion CalculatorDaily calories and cups of food for a dog from weight, life stage and body condition.Open calculator
(F + M ± 13) ÷ 2Height
Child Height PredictorPredicted adult height from the parents' heights, with a likely range.Open calculator
(113 ÷ slope) × (score − rating)Golf
Golf Handicap CalculatorHandicap Index from your best differentials, plus Course and Playing Handicap.Open calculator
amount × new ÷ oldCooking
Recipe Conversion CalculatorScale a recipe to any number of servings with grams and baker's percentages, plus a cooking unit converter by ingredient.Open calculator
for funJust for fun
Love CalculatorA playful name game: love percentage, FLAMES and love language tips. Not a real measure.Open calculator

Conversions & Online Tools

8 tools
words · FleschText
Word CounterWords, characters, sentences and reading time, five readability scores, keyword frequency and length limits.Open calculator
unit × factorLength
Length ConverterConvert between metric and imperial lengths, with every unit at once and tape-measure fractions.Open calculator
ρ = m ÷ VDensity
Density CalculatorSolve mass, volume or density for 40 common materials in metric and imperial units.Open calculator
1 – 3,999,999Numerals
Roman Numeral ConverterNumbers, Roman numerals and dates both ways, with standard or additive style and barred large numbers.Open calculator
text ↔ Base64Encoding
Base64 Encode / DecodeEncode or decode Base64 and Base64url with padding and MIME options and a bit-level view.Open calculator
%XXEncoding
URL Encode / DecodePercent-encode or decode URLs and query strings and see each parameter.Open calculator
bits = L × log₂ NSecurity
Password GeneratorRandom passwords, passphrases and PINs made in your browser, with entropy and guess time.Open calculator
NdS + MGames
Dice RollerRoll dice expressions like 4d6kh3 with the exact odds of every total.Open calculator

Which Calculator Should You Use?

Match what you are trying to work out to a starting calculator and the one to use next.

You Want To…Start WithThen UseWhy
Know how old you are, or count daysAge CalculatorDate CalculatorFind exact age first, then count days or business days to a deadline.
Renovate a roomSquare FootagePaint or TileMeasure the area once, then price the materials with a waste allowance.
Build a slab or garden bedConcreteGravel or MulchEstimate the volume, then the base or cover material.
Cut running costsElectricity CostCommute CostPrice appliances first, then the biggest driving cost.
Price a productMarkup & MarginBreak-EvenSet a price that earns the margin you want, then see how many units cover your costs.
Plan a school termGPA CalculatorFinal Grade NeededCheck where your GPA stands, then what one exam has to deliver.
How These Calculators Are Built

Methodology & Accuracy

SH
Suhaib HassanAuthor & calculator developer

Builds and maintains every CalculatePilot calculator, checking each formula and worked example by hand and re-verifying pages on a regular schedule.

Our methodologyFormula-first, example-checked

Calculations use standard double-precision (IEEE 754) arithmetic and results are rounded for display. Material and cost calculators are estimates that state their assumptions, such as waste allowances and coverage rates.

NIST Special Publication 811 (unit conversions)U.S. Department of Labor, Fair Labor Standards ActIRS mileage ratesEPA emission factorsISO 8601 datesStandard readability formulas
How to cite this page

CalculatePilot. (2026). Everyday calculators [Web application]. https://www.calculatepilot.com/other-calculators.html

Frequently asked questions

How accurate are the material estimates?

They are estimates. Concrete, paint, tile, mulch and lumber calculators add a waste allowance for cuts, spills and uneven ground, and coverage rates such as paint spread or bag yield vary by product. Use the result as a shopping guide and check the label or ask your supplier before ordering.

Do these calculators store the numbers I enter?

No. The calculations run in your browser and the values you enter are not sent to or stored on our servers. Like most websites, the site itself uses analytics and advertising cookies, so see our privacy policy for details.

Why can business-day and holiday results differ from my employer or contract?

Contracts and laws define how days are counted and which holidays apply. The date calculator lists US federal, UK, Canadian and Australian national holidays, but it does not include regional or one-off holidays. Add those as extra days off and check your own rules.

Are the electricity, fuel and commute costs exact?

They are estimates based on the rates and prices you enter. Your real bill may include fixed charges, tiered or time-of-use rates, taxes and changing fuel prices, so update the inputs with your latest bill or receipt.

Can I embed an Everyday calculator on my own website?

Yes. Most calculators have a free responsive embed, and the embed code is at the bottom of each page. Branding removal is available on a paid plan.

Embed an Everyday Calculator

Add a free, responsive calculator to your site or blog.

<iframe src="https://www.calculatepilot.com/embed/square-footage-calculator.html" width="100%" height="560" loading="lazy"></iframe>All embeds →