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 — ready whenever a reaction needs checking.
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Pediatric Dose Volume CalculatorConvert a weight-based dose (mg/kg) into the liquid volume (mL) to administer using the medication concentration. Quick, accurate dosing helper.
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Hydrometer Temperature Correction CalculatorCorrect a hydrometer specific gravity reading for sample temperature versus calibration temperature using the water-density polynomial. Free online tool.
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Proof to ABV Calculator (US)Convert alcohol proof to ABV (% alcohol by volume) instantly. Uses the US standard ABV = Proof ÷ 2. Enter any proof value to get the percentage.
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pH After Dilution CalculatorCalculate the pH of a strong acid or base after dilution. Enter C1, V1 and V2 to get the diluted concentration C2, pH and pOH instantly.
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Dilute Stock to Target Percent CalculatorCalculate how much stock solution and water you need to dilute a concentrated solution to a target percent concentration using V1 = (C2·V2)/C1.
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Chlorine Solution Dilution CalculatorCalculate how much stock chlorine (bleach) to dilute to reach a target ppm. Enter target ppm, final volume, and stock % to get the exact amount.
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Concentration to Absorbance CalculatorCalculate absorbance from concentration using the Beer-Lambert law (A = ε·c·l). Enter molar absorptivity, concentration and path length to get A and %T.
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Ksp from Solubility CalculatorCalculate the solubility product constant (Ksp) from molar solubility for any AnBm salt. Enter s, n, and m to get Ksp and ion terms.
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Serum Osmolality CalculatorCalculate estimated serum osmolality (mOsm/kg) from sodium, glucose, and BUN using the standard 2×Na + Glucose/18 + BUN/2.8 formula.
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Solute Mass from Mass Percent CalculatorCalculate the mass of solute in a solution from its mass percent (% w/w) and total solution mass. Free, instant chemistry concentration tool.
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Buffer pH After Adding Strong Acid/Base CalculatorCalculate the new pH of a buffer after adding strong acid or base using the Henderson-Hasselbalch equation. Enter pKa, moles of acid/base, and moles added.
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Buffer Ratio for Target pH CalculatorFind the conjugate base to acid ratio needed to hit a target pH from the buffer pKa using the Henderson-Hasselbalch equation.
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Molarity After Mixing Two Solutions (Same Solute)Calculate the final molarity when mixing two solutions of the same solute. Enter each concentration and volume to get M_final = (M1V1 + M2V2)/(V1 + V2).
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mEq/L CalculatorConvert mg/L to mEq/L for any electrolyte using its valence and atomic weight. Free milliequivalents per liter calculator with worked examples.
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ppm to Grains per Gallon CalculatorConvert water hardness from ppm (mg/L) to grains per gallon (gpg) instantly. Uses gpg = ppm / 17.118 for accurate water softener sizing.
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Number of Atoms CalculatorCalculate the number of atoms or particles from moles using Avogadro number (6.022 x 10^23). Fast, accurate chemistry conversion tool.
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Solution Density CalculatorCalculate the density of a solution from its total mass and total volume. Get results in g/mL and kg/m³ instantly with this free tool.
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Percent Solution Dilution CalculatorCalculate how much stock solution and diluent you need using C1V1=C2V2 with concentrations in percent. Get V1 and diluent volume instantly.
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Reagent Molarity CalculatorCalculate the molarity (mol/L) of a concentrated acid or reagent solution from its density, percent weight (%w/w) purity, and molar mass.
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Original Concentration from Dilution CalculatorReverse the dilution equation to find the original concentration C1 from the final concentration C2, final volume V2, and initial volume V1.
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Drug Infusion Rate from Dose CalculatorCalculate IV infusion pump rate in mL/hr from a weight-based dose (mcg/kg/min) and solution concentration. Fast, accurate drip rate tool for clinicians.
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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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Acid-Base Titration Volume CalculatorCalculate the titrant volume needed to reach the equivalence point in an acid-base titration using Va·Ca·na = Vb·Cb·nb. Free and instant.
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Dilution Factor CalculatorCalculate the dilution factor (fold) needed to reach a target concentration from a stock solution, plus stock and diluent volumes for a given final volume.
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 — 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 — 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.
