All Free Online Calculators
Browse the full collection of free calculators for finance, health, math, conversions and everyday decisions. Search instantly or jump straight to a category.
Count words, characters, sentences, and reading time.
Track attendance and how many classes you can still miss.
Work out how many minutes you can spend per question.
Estimate drywall sheets and joint compound for a room.
Estimate roof surface area, squares, and shingle bundles from pitch.
Find how many rolls of wallpaper you need.
Solve PV = nRT for pressure, volume, temperature, or moles.
Convert between pH, pOH, H+ and OH- concentration.
Heat needed to warm or cool a material: Q = m × c × ΔT.
How much meat to buy for a meal or party.
Engine size in cc, liters, and cubic inches from bore and stroke.
Predict 5K, 10K, half marathon, and marathon times from one result.
Convert pixels to rem, em, points, and percent for CSS.
Estimate file size from bitrate and duration.
See what regular deposits grow to with compound interest.
Find what a future sum is worth in today's money.
Work out the largest loan a monthly payment can support.
Average your purchase price across several buys and see profit or loss.
Calculate total pay including overtime hours and multiplier.
Estimate your ovulation day and fertile window from your cycle.
Body proportion index based on weight divided by height cubed.
Estimate kidney function using the Cockcroft-Gault formula.
Add, subtract, multiply, or divide two fractions.
Find how many standard deviations a value is from the mean.
Find square roots, cube roots, and any other root.
Volume and surface area for a cylinder and a cone of the same size.
Convert newtons, pound-force, kilogram-force, and more.
Convert newton-metres, pound-feet, pound-inches, and kgf-m.
Convert hertz, kilohertz, megahertz, gigahertz, and RPM.
See how much of the year has passed and how much is left.