🧮Calculators
Calculators cover finance, health, math, physics, engineering and everyday life: interest and loans, net salary, BMI, rule of three, conversions and more. Results are informational and educational — for important decisions, confirm with a professional and official sources.
2904 tools
Sweat Loss and Rehydration Calculator
Multiplies sweat rate in ml per hour by session length to get fluid lost, then adds 50 percent for the volume to drink back within 4 hours.
Cholesterol Ratio (Total/HDL)
Calculate the total cholesterol to HDL ratio, an indicator of cardiovascular risk. Below 3.5 is ideal; above 5 points to high risk for your heart.
Catan Victory Point Calculator
Total your Catan victory points from settlements at 1 each, cities at 2 each, longest road, largest army and victory point cards.
Carcassonne Score Calculator
Adds an end-of-game Carcassonne score: 2 points per completed city tile, 1 per unfinished city tile and per road tile, 9 per cloister, 3 per farm city.
Ticket to Ride Score Calculator
Adds route points by length (1, 2, 4, 7, 10 and 15), the value of completed tickets minus failed ones, and the 10-point longest route bonus.
Roulette Odds: European vs American
Compares single-zero and double-zero wheels, returning win probability, payout and the house edge of 2.70% or 5.26% for red/black, column and straight-up bets.
Wilks Score Calculator
Calculate the Wilks coefficient to compare powerlifting performance across athletes of different body weights. The standard for rankings and meets.
Sinclair Score for Olympic Weightlifting
Enter sex, body weight in kg and the total lifted to get the Sinclair-adjusted total from the 2021-2024 coefficients, comparing lifters across bodyweights.
IPF GL Points Calculator
Scores a powerlifting total against bodyweight using the official post-2020 IPF GL formula, with coefficients for classic and equipped, men and women.
xG (Expected Goals) Estimator
Enter shot distance in metres and angle in degrees, 0 from the side and 90 head-on, for an expected goals value from 0 to 1 from a simple logistic model.
Riegel Race Time Predictor (Marathon)
Enter a distance you have raced and its time to project any target distance: T2 = T1 x (D2/D1)^1.06. A 45 min 10K projects to 3h 27min over 42.195 km.
VDOT Calculator (Jack Daniels Formula)
Converts a race distance in kilometres and a finish time in minutes into a VDOT value, using the Daniels and Gilbert equations for training pace zones.
Negative Split Pace Calculator
Splits a target race time so the second half runs a chosen percentage faster than the first, returning the pace per kilometer for each half in minutes and seconds.
Swimming Pace per 100 m Calculator
Divides total distance in meters by total time in minutes to give the average pace in min:sec for every 100 m, so 1500 m in 25 min is 1:40.
Critical Swim Speed (CSS) Calculator
Enter your all-out 400 m and 200 m times in seconds to get (400 - 200) / (t400 - t200) in m/s, plus the matching pace per 100 m.
Cycling FTP Calculator (20-Minute Test)
Turns average power from an all-out 20-minute effort into Functional Threshold Power in watts, the 95% estimate used to set cycling training zones.
Cycling Power-to-Weight Ratio
Calculate your cycling power-to-weight ratio (W/kg) and see the Coggan classification, from untrained to world class. Enter power and body weight.
NBA Efficiency Rating (EFF)
Adds points, rebounds, assists, steals and blocks, then subtracts missed shots, missed free throws and turnovers for the classic NBA efficiency number.
FIDE Rating Delta
Applies the Elo formula to your rating, the opponent rating, the game result and the K factor, returning points gained or lost and the new rating.
Haversine Distance Between Two Coordinates
Enter two latitude and longitude pairs to get the great-circle distance in kilometers and miles, using Earth mean radius R = 6371 km.
Geographic Midpoint Calculator
Calculate the geographic midpoint between two coordinates (latitude and longitude). Useful for finding a meeting spot halfway between two places.
Distance from the Equator by Latitude (km)
Enter a latitude in degrees and get how far that parallel sits from 0 degrees: d = |lat| x 111.32 km, the same in both hemispheres.
Distance to the Greenwich Meridian
Enter latitude and longitude to get the east-west distance in km measured along the parallel: d = |longitude| × 111.32 × cos(latitude).
Earth Circumference at a Given Latitude
Type a latitude in degrees to get the length of that parallel: C = 2πR·cos(lat), with R = 6378.137 km, which gives 40075 km at the equator.
pH from [H+] Calculator
Calculate the pH of a solution from the molar concentration of H⁺ ions, using pH = −log₁₀[H⁺]. Find out whether the solution is acidic, neutral or basic.
pOH from Hydroxide Concentration
Enter the hydroxide concentration in mol/L and get pOH = -log10[OH-]. At 25 °C, subtracting the result from 14 gives the pH of the same solution.
Henderson-Hasselbalch Buffer pH Calculator
Enter pKa plus the molar concentrations of conjugate base and weak acid to get buffer pH from pH = pKa + log₁₀([A⁻]/[HA]). Equal amounts give pH = pKa.
Dilution (C1V1=C2V2) Calculator
Calculate solution dilutions using the C1·V1 = C2·V2 formula. Enter three values and find the final concentration or volume — essential in lab chemistry.
Molarity Calculator
Calculate the molarity of a solution from the solute mass, molar mass and volume. Find the concentration in mol/L for your lab preparations.
Mass Percent (w/w) Concentration Calculator
Divides solute mass by total solution mass and multiplies by 100: 25 g of solute in 250 g of solution returns 10 percent by weight.
Mole Fraction Calculator for a Solute
Divide moles of solute by the total moles in the mixture, x = n_solute / (n_solute + n_solvent), for a dimensionless value from 0 to 1.
Solution Normality Calculator
Multiplies molarity by the number of equivalents per mole to give normality in eq/L, the concentration unit used in acid-base and redox titrations.
Ideal Gas Law: Solve for Pressure (PV = nRT)
Enter moles, temperature in kelvin and volume in liters to get P = nRT/V in atm, with R = 0.08206 L atm per mol per kelvin.
Molar Mass from Gas Density
Enter density in g/L, temperature in K and pressure in atm: M = ρ·R·T/P with R = 0.08206. A gas at 1.96 g/L, 273 K and 1 atm gives 43.9 g/mol.
Moles to Atoms Calculator (Avogadro Number)
Enter the amount of substance in moles and get the particle count in scientific notation: atoms = n × 6.02214076e23, the exact SI value.
Boyle's Law Calculator
Calculate Boyle's Law (P1·V1 = P2·V2) for gases at constant temperature. Find the final volume or pressure of a gas from the other values.
Charles's Law Calculator
Calculate Charles's Law (V1/T1 = V2/T2) for gases at constant pressure. Find how a gas volume changes with temperature, in kelvin.
Gay-Lussac's Law Calculator
Calculate Gay-Lussac's Law (P1/T1 = P2/T2) for gases at constant volume. Find how a gas pressure changes with temperature, in kelvin.
Combined Gas Law Calculator: Solve for V2
Solves P1V1/T1 = P2V2/T2 for the final volume from both pressures, the starting volume and both absolute temperatures in kelvin.
Percent Yield Calculator
Divides the mass actually recovered from a reaction by the theoretical mass predicted by stoichiometry, both in grams, and returns the percent yield.
Theoretical Yield Calculator
Multiplies moles of the limiting reagent by the stoichiometric ratio and by the product molar mass to give the maximum mass in grams a reaction can form.
Limiting Reagent (Two Reagents)
Enter the moles and stoichiometric coefficient of two reagents; the smaller mole-to-coefficient ratio wins and is reported as the limiting reagent.
Freezing Point Depression (Kf, molality, i)
Multiply the cryoscopic constant, the molality in mol/kg and the van't Hoff factor to see how many degrees Celsius the solvent freezing point drops.
Michaelis-Menten Reaction Rate
Solves v = Vmax·[S]/(Km + [S]) from maximum velocity, substrate concentration and the Michaelis constant, giving the rate in the same units as Vmax.
Percent Enzyme Inhibition Calculator
Enter the uninhibited rate v0 and the inhibited rate vi to get the drop in activity: (1 − vi/v0) × 100. With v0 = 100 and vi = 30 the answer is 70%.
Serial Dilution Total Factor Calculator
Give the ratio per step (10 means 1:10) and the number of steps to get the combined factor 1:r^n, so 5 steps at 1:10 return 1:1.00e+5.
Hemocytometer Cell Density Calculator
Enter cells counted, how many large squares you counted and the dilution factor to get cells/mL on a Neubauer grid: (count / squares) x dilution x 10^4.
Bacterial Doubling Time Calculator
From the initial count N0, the final count N and the elapsed minutes, get the log-phase generation time: Td = t · ln(2) / ln(N/N0), in minutes.
Specific Growth Rate (µ) Calculator
Enter initial and final cell counts plus elapsed hours to get ln(N/N0)/t in 1/h: going from 1000 to 64000 in 4 h returns 1.0397 per hour.
Punnett Square: Two-Allele Cross
Pick the genotype of each parent, AA, Aa or aa, and get the offspring ratio for a single gene counted out of the four boxes: AA, Aa and aa.
Hardy-Weinberg p² + 2pq + q²
Enter the dominant allele frequency p and get the three genotype frequencies at Hardy-Weinberg equilibrium: AA as p², Aa as 2pq and aa as q², with q = 1 − p.
DNA GC Content Calculator
Paste a DNA sequence and get the guanine plus cytosine share: %GC = (G+C)/(A+T+G+C) × 100. Anything that is not A, T, G or C is dropped first.
Oligo Melting Temperature (Wallace Rule)
Estimates the melting temperature of a DNA oligo with the Wallace rule, Tm = 4·(G+C) + 2·(A+T) in °C, intended for primers shorter than 14 bases.
Protein Molecular Weight from Amino Acid Sequence
Adds the residue masses of a one-letter amino acid sequence and subtracts 18.015 Da per peptide bond, returning protein molecular weight in daltons.
Voltage Divider Calculator (Vout)
Give Vin, R1 and R2 to get Vin x R2 / (R1 + R2). A 9 V supply across a 1 kohm and 2.2 kohm pair reads 6.19 V at the tap, before any load current.
RC Time Constant Calculator
Resistance in ohms times capacitance in farads gives tau in seconds. 10 kohm with 1 uF returns 0.01 s, and a capacitor is near full charge at 5 tau.
RL Circuit Time Constant Calculator
Divides inductance L in henries by resistance R in ohms to get tau in seconds, the time in which the current reaches 63.2 percent of its final value.
LC Resonant Frequency Calculator
Enter inductance in henries and capacitance in farads to get the tank resonance in hertz from f = 1 / (2π·√(L·C)). 1 mH with 1 nF resonates at 159 kHz.
Two Resistors in Parallel Calculator
Product over sum for a pair of resistors, R1 times R2 divided by R1 plus R2: 1000 Ω with 2200 Ω gives 687.5 Ω of equivalent resistance.
Two Resistors in Series: Equivalent Resistance
Add two resistor values in ohms to get Rs = R1 + R2, always higher than either part on its own: 1000 plus 2200 returns 3200 ohms.