Health & calculations

Calculate and predict your next period date based on cycle length. Enter your last period start date to see predicted menstrual cycle dates on a visual calendar.

Calculate calories and macronutrients for any serving size based on nutrition label values per 100g

Calculate how long it takes for your fingernails to grow to a desired length, or predict nail growth over a time period

Calculate horse gestation dates, due dates, and track pregnancy progress for mares

Estimate how long your tattoo will stay vibrant. Calculate fade time based on ink color, body location, sun exposure, skin type, and aftercare.

Plan for a secure retirement. Estimate your savings amount based on age, contributions, and expected returns with inflation adjustment.

Calculate how long it will take to grow your hair to a desired length based on hair type, age, and health factors

Convert between diopters and focal length. Calculate lens power for eyeglasses, contact lenses, and optical systems.

Calculate calories burned during exercise based on your heart rate, age, weight, and gender using the scientifically validated Keytel formula.