Family, Health & Culture

Due date, dog age, water intake, calendar converters (Hijri, Hebrew, Chinese), color palettes and contrast checker – helpful everyday tools, free.

A due date calculator, pregnancy week calculator and ovulation calculator, BMI calculator, water intake and calories burned, dog age and cat age, calendar converters (Hijri, Hebrew, Chinese, Persian) and Ramadan dates, plus color palettes, a color converter, a contrast checker and a metronome for practicing music. Health figures are estimates with sources and do not replace medical advice.

108 tools

Most used

BMI calculator (WHO categories)BMI calculator in lb and ft/in or kg and cm: your body mass index with WHO category on a colour scale, healthy weight range for your height and BMI Prime.
Online metronomeFree online metronome: 20–300 BPM, time signatures from 2/4 to 12/8, accents per beat, subdivisions and tap tempo. Sample-accurate, no app needed.
White Noise & Rain SoundsFree white, pink and brown noise plus rain sounds with thunder, looping endlessly in your browser. Mix them freely, set a sleep timer with gentle fade-out.
Blood Pressure Chart and CalculatorBlood pressure chart with calculator: enter systolic and diastolic values to see the ACC/AHA, ESC and ESH category, pulse pressure and mean arterial pressure.
Calorie CalculatorCalorie calculator: enter age, sex, height, weight, activity and a weekly weight goal to get your daily calories for losing, keeping or gaining weight.
Creatinine Clearance Calculator (Cockcroft-Gault)Creatinine clearance calculator using Cockcroft-Gault: enter age, sex, weight, height and creatinine to get CrCl for actual, ideal and adjusted body weight.
Guitar chords and chord finderGuitar chords with diagrams in several positions, fingering and sound – plus capo, alternate tunings, a left-handed view and a reverse chord finder. Free.
GFR Calculator (eGFR, CKD-EPI 2021)GFR calculator using the CKD-EPI 2021 equation: enter creatinine in mg/dL or µmol/L, age and sex to get eGFR, the KDIGO stage G1–G5 and the full working.

All tools

Guitar tuner: tune guitar and ukuleleFree online guitar tuner using your microphone: standard, Drop D, half step down, Open G, DADGAD, bass, ukulele, violin and chromatic, with reference tones.
Prayer Times CalculatorPrayer times for today and the whole month: Fajr, Dhuhr, Asr, Maghrib and Isha for your location. Choose ISNA, MWL, Moonsighting or Diyanet; export to calendar.
TDEE calculator – your daily calorie needsTDEE calculator: estimate the calories you burn per day from your basal metabolic rate and activity, plus calorie targets to maintain, lose or gain weight.
Online PianoOnline piano with 5 octaves: play by keyboard, mouse, touch or MIDI, see the chord you hold, record your melody and share it as a link. Free, no sign-up.
Key Finder: Which Key Fits My Notes?Key finder: drop an audio file for a local key estimate with Camelot code, relative key and tuning – or enter chords or notes to see every matching key.
Corrected Calcium CalculatorCorrected calcium calculator using the Payne albumin correction: enter total calcium and albumin in mg/dL or mmol/L and get the result in both units.
Due Date CalculatorEstimate your due date from the last menstrual period (with cycle length) or conception date – plus current pregnancy week, trimester and days to go.
BSA Calculator (Body Surface Area)BSA calculator with the Mosteller, Du Bois and Haycock formulas: enter height and weight in cm/kg or in/lb and get body surface area in m² with the working.
Interactive circle of fifthsInteractive circle of fifths: tap a key for its signature, relative key, diatonic chords, progressions like I–V–vi–IV and modes – with audio and printable PDF.
BMR and daily energy needs calculatorCalculate your basal metabolic rate with the Mifflin-St Jeor equation and your total daily energy needs with FAO/WHO activity levels (PAL), in kcal and kJ.
Color palette generatorBuild matching colors from one base color: complementary, analogous, triadic, square, split-complementary or monochrome – with HEX, RGB and HSL values.
Color picker from image (eyedropper)Get color codes from any image: open a photo, click a spot and copy the HEX, RGB or HSL value – plus the main colors. No upload, it all stays in your browser.
Macro calculator – daily protein, fat and carbsMacro calculator: estimate your daily calories from height, weight and activity, then split them into grams of protein, fat and carbs – with the working shown.
FENa Calculator (Fractional Excretion of Sodium)FENa calculator: enter sodium and creatinine in urine and plasma to get the fractional excretion of sodium in percent, with formula, working and FEUrea.
ANC Calculator (Absolute Neutrophil Count)ANC calculator: enter the white blood cell count and the percentages of segs and bands to get the absolute neutrophil count in cells/µL and × 10⁹/L.
Body Fat Calculator (U.S. Navy Method)Estimate your body fat percentage from height, neck, waist and hip measurements using the U.S. Navy equations by Hodgdon and Beckett (1984). In inches or cm.
Binaural beats generatorBinaural beats online: set carrier and difference frequency, a separate sine tone for each ear, with timer and headphone test. No health claims.
Weight loss calculator – your goal dateWeight loss calculator: enter your calorie deficit, body data and goal weight to see how long losing weight takes and the date you could reach your target.
Tone generator: play any frequencyFree online tone generator: sine, square, triangle or sawtooth from 1 to 20,000 Hz, with frequency sweep, note names (A4 = 440 Hz) and a volume warning.
Meditation timer with gongOnline meditation timer: choose a duration, settling-in time and interval bells, with a soft gong at start and end. Stays accurate in background tabs.
BAC CalculatorBAC calculator using the Widmark formula: enter sex, weight, drink volume, strength and time to get an estimated blood alcohol level with the working.
Anion Gap Calculator with Albumin CorrectionAnion gap calculator: enter sodium, chloride and bicarbonate (potassium optional) to get the serum anion gap, the albumin-corrected value and the working.
Waist to height ratio calculatorWaist to height ratio (WHtR) calculator: waist divided by height, rated by the NICE guideline, with your target waist at a ratio of 0.5 and how to measure.
Color contrast checker (WCAG 2.2)Check the contrast between text and background colors: WCAG 2.2 contrast ratio with AA/AAA ratings for normal text, large text and UI components.
Ovulation Calculator: Estimate Your Fertile WindowEstimate ovulation and your fertile window with the calendar method for the next 3 cycles. An estimate only – this is not a method of contraception.
Color MixerColor mixer for screen colors: blend two colors, lighten or darken a color and build gradients. Get HEX, RGB, HSL and CSS color-mix – free, in your browser.
One Rep Max (1RM) CalculatorEstimate your one-rep max from weight and reps using the Epley and Brzycki formulas, with a %1RM chart for 1 to 10 reps. Works in kg or lb.
Sleep Cycle CalculatorSleep calculator: what time to go to bed if you wake up at 7 am, or when to set the alarm. 4 to 6 sleep cycles of about 90 minutes as a rule of thumb.
Ideal weight calculator: your healthy weight rangeFind your healthy weight range from your height: the weights that give a BMI of 18.5 to 24.9 (WHO), in lb and kg – instead of one questionable ideal number.
Running pace calculatorCalculate running pace per km or mile, finish time or distance. With speed in km/h and mph, splits per km or mile and times for 5K, 10K, half and marathon.
Golf handicap calculatorGolf handicap calculator using the World Handicap System: Handicap Index from your rounds (score, course rating, slope) and the course handicap for any course.
Daily water intake calculatorHow much water should you drink a day? Daily fluid and total water intake by age, sex, pregnancy and breastfeeding, based on EFSA and German DGE values.
Interval Timer (HIIT)Free interval timer for HIIT and circuit training: set work, rest, rounds, sets and get-ready time, with countdown beeps and fullscreen. No app, no sign-up.
VO2 Max Calculator (Cooper Test)Estimate your VO2max from the 12-minute run: enter the distance in meters or miles and get ml/kg/min using the Cooper equation (JAMA 1968).
Tabata TimerFree Tabata timer: 20 s work, 10 s rest, 8 rounds, countdown beeps and get-ready time. Multiple sets, fullscreen, runs in your browser with no app needed.
Tap BPM: tap along to find the tempoTap BPM online: tap the pad or any key in time with the music and instantly see the BPM, how steady your timing is, plus half and double tempo.
Protein intake calculator – protein per dayProtein intake calculator: grams of protein per day by official reference values for adults, seniors, pregnancy and breastfeeding, and ranges for athletes.
HTML color namesHTML color names: all 148 CSS colors with HEX, RGB, HSL and text contrast, with search and a color-family filter. One click copies the value. Free, no sign-up.
Recipe nutrition calculatorRecipe nutrition calculator: paste your ingredients, enter the servings and see calories, protein, fat, carbs and salt per serving – with public USDA data.
Calories burned calculatorEstimate calories burned in 30 sports and activities from MET value, body weight and duration per the 2024 Compendium, in kg or lb, with a personal correction.
Hebrew Date Converter (Jewish Calendar)Convert a Gregorian date to the Jewish (Hebrew) calendar and back – with month names, leap years (Adar I/II) and the date of Rosh Hashanah.
Dog age calculator: dog years to human yearsHow old is your dog in human years? Uses the 16·ln(age)+31 formula (Wang et al. 2020) and the AVMA size chart, compares both and shows the senior age.
Animated Breathing ExerciseAnimated breathing exercise in your browser: box breathing 4-4-4-4, 4-7-8, calm breathing 5-5 or your own rhythm. Follow the circle, soft tones, no app.
Ramadan Calendar: Start and End DatesWhen is Ramadan? Start, last day of fasting and Eid al-Fitr for 2025 to 2035, calculated with the Umm al-Qura calendar – with a note on moon sighting.
Drum machine: make beats in your browserFree online drum machine: 16-step sequencer with kick, snare, clap, hi-hats and tom, adjustable tempo and swing, share your beat as a link. No sign-up needed.
Lean body mass calculatorLean body mass calculator: estimate your fat-free body mass (LBM) from height and weight with the Boer and Hume formulas, or from your body fat percentage.
Birthstone by MonthFind your birthstone by month: which gemstone belongs to your birth month? All twelve months with color, traditional meaning and alternative stones.
Heart Rate Zone CalculatorCalculate your training heart rate zones: enter your max heart rate or estimate it with Tanaka, then get zones as % of max HR or with the Karvonen method.
Cat age calculator: cat years to human yearsHow old is my cat in human years? Convert cat age, kittens in months too, with the AAFP-AAHA chart and see the life stage from the 2021 AAHA/AAFP guidelines.
Boxing timer with rounds, rest and bellFree boxing timer: set round length, rest and number of rounds, hear a bell at the start and end of every round. Presets for amateur, pro, Muay Thai and MMA.
Zodiac sign calculator: sun, moon and risingZodiac sign calculator by date, time and place of birth: sun sign to the minute, rising sign and moon sign, plus the exact sign dates of your birth year.
Scale FinderScale finder: notes of major, minor, modes, pentatonic, blues and whole-tone scales for every root, with correct accidentals, steps, triads and relative key.
Persian Calendar Converter (Solar Hijri)Persian calendar converter: today’s date in the Solar Hijri (Jalali) calendar, or convert any Gregorian date and back – with year 1405, leap years and Nowruz.
Pregnancy Week CalculatorHow many weeks pregnant am I? Work out your pregnancy week from the last period or due date – weeks and days, trimester, month and days until the due date.
Dog food calculatorDog food calculator: how much dry and wet food does your dog need per day? Based on weight and life stage, with grams or ounces per meal and a range.
Bike Gear Ratio CalculatorBike gear ratio calculator: enter chainring, cog, tire and cadence to get the gear ratio, gear inches, development in meters and your speed. Free, no sign-up.
Zakat calculator: how much zakat do you owe?Free zakat calculator: enter cash, savings, gold, silver, investments and debts, pick the nisab and see your zakat (2.5%) at once. With the working, no sign-up.
Steps to calories calculatorSteps to calories: from step count, step length, weight and pace get calories burned, distance and time, based on the Compendium of Physical Activities.
Convert steps to km (kilometres)Convert steps to km and miles: 10,000 steps are 7 km (4.35 miles) at a 70 cm step. Enter your own step length – also converts a distance in km into steps.
Fret Calculator: Fret Positions from Scale LengthFret calculator: enter the scale length and get the position of every fret from the nut and from the bridge for guitar and bass, in millimetres and inches.
Aquarium Volume CalculatorAquarium volume calculator: from outer size, glass thickness, water level and substrate get the real water volume in gallons and liters and the total weight.
Race time predictor (Riegel formula)Predict your finish time for 5K, 10K, half marathon, marathon or any distance from a recent race result, using Riegel’s formula, with pace per km and mile.
Intermittent fasting calculator and timerIntermittent fasting calculator: pick your eating window start (16:8, 14:10, 18:6, 20:4) and see eating and fasting times plus a timer for the current phase.
Create a Family TreeCreate a family tree online: add people with parents and partners and generations are arranged automatically. Export as PNG, SVG or GEDCOM, or print it.
Chord TransposerChord transposer: paste lyrics with chords, pick the new key and move every chord automatically, including slash chords and flats or sharps. Free, no sign-up.
Hijri Date Converter (Islamic Calendar)Convert a Gregorian date to the Islamic Hijri calendar and back – using Umm al-Qura (Saudi Arabia) or the tabular calendar, with month length.
A1C calculator: convert A1C and average glucoseA1C calculator: convert A1C % to estimated average glucose (eAG) in mg/dL and mmol/L, to IFCC mmol/mol, or work back from your average blood sugar.
Alcohol calorie calculatorAlcohol calorie calculator: from amount, alcohol content and sugar get calories in beer, wine or spirits, with grams of pure alcohol and a comparison table.
Apgar Score CalculatorApgar score calculator: rate skin colour, heart rate, reflexes, muscle tone and breathing from 0 to 2 each and get the total and what it means at 5 minutes.
Audiobook speed calculatorAudiobook speed calculator: enter the length and playback speed to see how long the book takes at 1.25×, 1.5× or 2×, the time you save and days to finish.
School backpack weight calculatorBackpack weight calculator for kids: what percent of body weight the school bag is, and the most it should weigh at 10 % and at the 15 % limit of the AAP.
Barbell Plate CalculatorBarbell plate calculator: enter target weight and bar weight and see which plates go on each side, in lb or kg, with warm-up steps. Free, no sign-up needed.
Batting average calculatorBatting average calculator with OBP, slugging and OPS, plus ERA and WHIP for pitchers – using the formulas of Rule 9.21 of the Official Baseball Rules.
Bike Chain Length CalculatorBike chain length calculator: enter largest chainring, largest cog and chainstay length to get the link count and chain length. Free, no sign-up.
Blood type calculator: which blood types can the child have?Blood type calculator for parents: possible ABO blood types and Rh factor of a child, with Punnett square percentages for every genotype combination.
Caffeine calculatorCaffeine calculator: add up coffee, espresso, tea, cola, energy drinks and chocolate and compare with the EFSA safe levels – 400 mg a day, 200 mg in pregnancy.
Capo CalculatorCapo calculator: pick the key you want and see which capo fret and chord shapes to play, or work out the sounding key from a shape and capo. Free tool.
Cat Food CalculatorCat food calculator: how much wet and dry food does your cat need per day? Based on weight and life stage, with grams or ounces per meal.
Chinese Calendar Converter and Zodiac SignConvert a date to the Chinese lunar calendar and back: year in the 60-year cycle (Heavenly Stem, Earthly Branch), zodiac animal, element, New Year.
Color converter: HEX, RGB, HSL, HSV, CMYKConvert color codes: HEX to RGB, RGB to HEX, HSL, HSV, HWB and CMYK – type any format or use the color picker and copy the result, right in your browser.
Delay Time Calculator (BPM to Milliseconds)Delay time calculator: enter the tempo in BPM and read the delay in ms for quarter, eighth, sixteenth, dotted and triplet notes. Free, no sign-up needed.
Dog and Cat Pregnancy CalculatorDog and cat pregnancy calculator: due date range from the mating date, LH surge or diestrus, day of pregnancy and check-up dates based on the MSD Vet Manual.
Frequency to Note Converter (and Back)Frequency to note converter: turn Hz into the nearest note with the deviation in cents, MIDI number and wavelength, or a note into Hz. Adjustable A4, free.
FTP zones calculator for cycling power zonesFTP zones calculator: the seven Coggan cycling power zones in watts from your FTP or a 20-minute test, with heart rate ranges from your threshold.
Hiking time calculatorHiking time calculator for distance, ascent and descent by DIN 33466, the SAC rule or Naismith, with breaks, pace and arrival time. Free, in your browser.
Horse Weight CalculatorHorse weight calculator without a scale: enter heart girth and body length into the Carroll and Huntington formula to see the weight in kg and lb. Free tool.
How many laps is a mile?How many laps is a mile in a 25 yard, 25 meter or 50 meter pool, and how many laps on a 400 m track in each lane? Works for any distance.
How Tall Will My Child Be?How tall will my child be? Estimate the genetic target height from mother’s and father’s height (Tanner formula) with the usual range. A guide, not a diagnosis.
Incubation Calendar: Hatch Date from the Setting DateIncubation calendar: work out the hatch date for chicken, duck, goose, turkey, quail, pheasant and pigeon eggs from the setting date, or backwards. Free.
Mayan calendar converterMayan calendar converter: turn any date into the Long Count, the Tzolk’in day and the Haab’ date, or a Long Count back into our calendar – GMT correlation.
Music Interval Calculator: Thirds, Fifths and MoreMusic interval calculator: pick two notes and see the interval name, semitones, inversion, plus the ratio and cents in just intonation and equal temperament.
Oxygen at altitude calculatorOxygen at altitude calculator: air pressure, oxygen partial pressure and how much oxygen each breath holds compared with sea level, with a chart by altitude.
Power to weight ratio for cyclingCycling power to weight ratio in W/kg, plus climbing speed and vertical metres per hour from power, weight and gradient, or the watts needed for a target speed.
Pregnancy weight gain calculatorPregnancy weight gain calculator: recommended gain by week and in total for your pre-pregnancy BMI, in pounds or kg, based on the IOM guidelines – twins too.
Rowing split calculatorRowing split calculator: convert a 500 m split to watts, watts to split, times for 2000 m, 5000 m and a marathon, or the split from distance and time. Free.
SWOLF CalculatorSWOLF calculator: add the time and strokes for one pool length, or average a whole swim, and see your SWOLF score, pace per 100 and distance per stroke.
Texas child support calculator 2026Texas child support calculator 2026: guideline support from gross pay – net resources after taxes, 20% to 40% by number of children, $11,700 cap.
Triathlon Time CalculatorTriathlon time calculator: enter swim pace, bike speed, run pace and transitions to get your finish time and splits for sprint, standard or long distance.
Vitamin D: IU to mcg converterConvert vitamin D from IU to mcg and back: 1 mcg = 40 IU, so 1,000 IU = 25 mcg. With the daily intakes and upper limits for each age from MedlinePlus.
Wilks calculator with DOTS and IPF GL pointsWilks calculator for powerlifting: enter bodyweight and total to get Wilks, DOTS and IPF GL points side by side – classic, equipped and bench only.