Reading the numbers
A percentage depends on what it divides by
Going from 100 to 50 is a 50% fall; getting back is a 100% rise. The move is the same size but the numbers differ because the base differs. Check what the base is before comparing two percentages.
Two of the three fuel units run backwards
km/L asks how far one litre goes, so higher is better. L/100km asks how many litres 100 km takes, so lower is better. They describe the same car, and reading an imported spec sheet with the wrong one in mind is how the mistake gets made.
A date needs to say whether the first day counts
Anniversaries and legal deadlines count from different places — one includes the starting day, the other begins the day after. The date calculator gives both, because the same word points at two different dates.
What are you trying to work out
- You just need a calculatorCalculator
- What percent that is, or how much it changedPercentage calculator
- Inches, pounds and °F into metricUnit converter
- How many days until a dateDate calculator
- What a loan will cost in interestLoan repayment calculator
- Dividing a bill between several peopleSplit the bill
- What the petrol for a trip costsFuel cost calculator
- What time it is somewhere elseWorld clock and time zones
Tools in Everyday
24 tools
- Calculator🌐Type the whole expression, precedence and all
- Random picker🌐Pick one of your options at random
- Percentage calculator🌐What percent it is, and how much it changed
- Unit converter🌐Length, weight, area, volume, temperature, speed
- Date calculator🌐Days until, days since, D-day
- Loan repayment calculator🌐Equal payment, equal principal, grace period
- Split the bill🌐Each share, and what is left over
- Fuel cost calculator🌐What the petrol for this trip costs
- World clock and time zones🌐What time it is there, and when to call
- BMI and reference weight🌐Body mass index, and weights at each cut-off
- BMR and TDEE calculator🌐Resting burn, and what a day actually costs
- Body fat calculator🌐The US Navy tape method — no calipers
- Target heart rate calculator🌐Maximum heart rate and Karvonen zones
- Waist ratio calculator🌐Waist-to-hip and waist-to-height together
- Child height predictor🌐Mid-parental height, and how wide the range is
- Macro calculator🌐Split a day's calories into carbs, protein and fat
- Due date calculator🌐Naegele's rule with gestational age and the term window
- Milestone date calculator🌐Day 100, day 1000, and what day you are on
- GCD and LCM calculator🌐Prime factors, divisors and primality in one place
- Permutation and combination calculator🌐nPr, nCr, repetition, and the probability that follows
- Mean and standard deviation calculator🌐Median, mode, quartiles and outliers too
- Quadratic equation solver🌐Discriminant, roots and the vertex
- Ohm's law calculator🌐Any two of voltage, current, resistance and power
- Transfer time calculator🌐How long a file takes on a given connection
Common questions
Is anything I type sent to a server?
No. There is no server here to receive it — every calculation finishes in the browser. A date of birth or a loan amount stays in this browser.
Where do the figures come from?
The inch and pound are exact under the 1959 international yard and pound agreement, the SI defines the rest, and time zones come from the IANA data already inside your browser. Each screen names what it relied on.
Why are public holidays and exchange rates left out?
They change every year, so anything written down here would go stale. These tools only cover sums with one right answer; anything that needs data fetched lives under the statistics group.
Can I keep or pass on a result?
What you type is saved in this browser and is still there when you come back. The date, loan and fuel screens can also make a share link — the values travel inside the address, so look at what it carries before sending it on.