From preparing solutions to maintaining a safe pool, this collection handles the numbers across a broad sweep of chemistry. Reach for the Molarity Calculator to set up concentration work, the Formal Charge Calculator to map electron distribution, the Half-Life Calculator for radioactive decay problems, or the Pool Chemistry Calculator to keep chlorine and pH in balance.
The Popular list shows which tools students, lab workers, and hobbyists use most; the Trending tab highlights calculators gaining traction right now. Every tool is completely free, needs no login, and works on desktop or mobile ā ready whenever a reaction needs checking.
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Common-Ion Effect CalculatorConvert Ksp to molar solubility for any salt MxAy. Enter Ksp and stoichiometric coefficients to find s and ion concentrations in mol/L.
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Wavelength to Color and Energy CalculatorConvert frequency to wavelength with Ī» = c/f. Enter frequency in Hz, kHz, MHz, GHz, or THz to get wavelength in meters and nanometers instantly.
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Mass Percent to Moles CalculatorCalculate moles of solute from molarity and volume using n = M Ć V. Enter mol/L and liters to get the amount of substance in moles instantly.
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Path Length from Absorbance CalculatorCalculate solution concentration from absorbance using the Beer-Lambert law: c = A / (Īµ Ā· l). Enter absorbance, molar absorptivity, and path length.
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% w/v to % w/w CalculatorConvert between % w/v, mg/mL and ppm instantly. 1% w/v = 10 mg/mL = 10000 ppm. Fast solution concentration converter for lab and pharmacy.
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Percent by Mass of Element in Compound Calculator (with Mass in Grams)Find the mass of an element within a compound sample. Enter atoms, atomic mass, molar mass and total mass to get grams and percent by mass.
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De Broglie Frequency CalculatorSolve the combined gas law PāVā/Tā = PāVā/Tā for the final pressure Pā. Enter initial pressure, volume, temperature plus final volume and temperature.
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Grams per Gallon Fertilizer to PPM CalculatorConvert grams of fertilizer per gallon or liter into N-P-K ppm. Enter weight, nutrient percentage, and water volume to get parts-per-million instantly.
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Percent Yield CalculatorCalculate percent yield from actual and theoretical yield. Free chemistry tool to measure reaction efficiency instantly with the percent yield formula.
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Grams to Moles CalculatorConvert grams to moles instantly. Enter the mass in grams and molar mass (g/mol) to find the amount of substance in moles using n = m / M.
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Buffer pH CalculatorCalculate the pH of a buffer solution from pKa and conjugate base/acid concentrations using the HendersonāHasselbalch equation. Free and instant.
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Henderson-Hasselbalch CalculatorCalculate buffer solution pH with the Henderson-Hasselbalch equation from pKa and the conjugate base to weak acid concentration ratio.
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Radioactivity (Becquerel) CalculatorCalculate radioactivity in becquerel (Bq) from the mass, half-life and molar mass of a pure radioisotope. Includes 23 isotopes and Bq per gram.
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Ratio Unit Conversion CalculatorConvert a dimensionless ratio between percent, permille, permyriad (basis points), ppm, ppb, ppt and ppq instantly. Free universal ratio unit converter.
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Energy to Wavelength CalculatorConvert photon energy (in eV or joules) to wavelength using Ī» = hc/E. Get wavelength in nm and meters plus frequency instantly.
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Specific Heat CalculatorCalculate specific heat capacity from heat energy, mass, and temperature change using c = Q / (mĀ·ĪT). Fast, accurate physics tool with worked example.
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Moles to Grams to Atoms CalculatorConvert mass to moles to particles fast. Enter grams and molar mass to find the number of atoms or molecules using Avogadro's number.
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Oxidation Number CalculatorCalculate the unknown oxidation number of an element in any molecule or ion using the rule that all oxidation states sum to the overall charge.
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Moles to Grams CalculatorConvert moles to grams instantly. Enter the amount in moles and the molar mass (g/mol) to find mass using mass = moles Ć molar mass.
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Water to Add for Dilution CalculatorFind how much water to add to dilute a solution from one concentration to a lower target. Uses V_water = V1Ā·(C1āC2)/C2. Free and instant.
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Acid Dilution Preparation CalculatorCalculate how much concentrated stock acid and water you need to prepare a dilute acid solution at a target molarity and volume using M1V1 = M2V2.
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Final Concentration After Mixing Two Solutions CalculatorCalculate the final concentration when two solutions are mixed using C_final = (C1Ā·V1 + C2Ā·V2)/(V1+V2). Free, fast, and unit-agnostic.
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Molarity to Mass Percent CalculatorConvert molarity (mol/L) to mass percent (% w/w) using molar mass and solution density. Free, instant chemistry concentration converter.
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Percent by Mass (%w/w) CalculatorCalculate percent by mass (%w/w) of a solution from the mass of solute and the total mass of solution. Free, instant chemistry concentration tool.
Frequently asked questions
What chemistry problems can these calculators solve?
The collection spans general chemistry (molarity, formal charge, partial pressure, percent ionization), nuclear chemistry (half-life), biochemistry (GC content of nucleic-acid sequences), practical water treatment (pool chemistry), and periodic-table properties (electronegativity). Whether you are in a classroom, a teaching lab, or treating your backyard pool, there is a relevant tool here.
How accurate are the chemistry results?
All tools apply standard chemical formulas and accepted constants ā for example, Dalton's law for partial pressure and standard decay equations for half-life. Results match textbook precision for typical homework and lab-prep use. For safety- or code-critical work such as industrial chemical handling or regulated processes, verify against the governing standard and have a qualified chemist or engineer review your figures.
Is there any cost or registration requirement?
None. All calculators are free with no sign-up needed. Load the page, enter your values, and get results immediately ā as many times as you like.
Do you store the chemical data or concentrations I input?
No. All calculations are performed in your browser and no input data is transmitted to or stored on our servers. Your concentration values, isotope data, and other figures remain entirely on your device.
How can I find the most-used chemistry calculators?
The category listing is ordered by real usage, putting the most popular tools at the top. The Trending and Recently Added tabs let you discover newer entries or spot which calculators are currently seeing increased traffic.
