Lab Utilities, Dilutions & Unit Tools
Every lab utilities, dilutions & unit tools calculator on CalcEngines — unit converters, derived indices and interpretive tools, each with its formula, a worked example and the reference intervals it is judged against.
21 calculators in this section
- Beer-Lambert Concentration from Absorbance CalculatorTurn an absorbance reading into a concentration using the molar extinction coefficient and the true optical path length — which, in a microplate, is neither 1 cm nor the same from well to well.
- Buffer pH from pKa CalculatorCalculate the pH of a buffer from its pKa and the ratio of conjugate base to acid — and see why the answer on the bench at 37 °C is not the answer you set at the pH meter.
- C1V1 = C2V2 Dilution CalculatorWork out how much stock solution to take for a given final concentration and volume — and, just as important, how much diluent to add to it.
- Centrifuge RCF to RPM CalculatorConvert a required force in × g into the rotor speed to dial up on your own centrifuge — the direction you need when transferring a published method.
- Centrifuge RPM to RCF CalculatorConvert rotor speed in revolutions per minute to relative centrifugal field in × g, using your own rotor radius — the number a method should actually specify.
- Citrate Anticoagulant Volume Adjustment CalculatorWork out how much citrate should remain in a coagulation tube when the haematocrit is above 55%, using the CLSI H21-A5 formula — and why the same correction is not made for anaemia.
- Enzyme Activity Unit ConverterConvert catalytic activity between U/L, IU/L, mU/mL, U/mL, µkat/L and nkat/L — and see why the same number from two laboratories need not mean the same thing.
- Haemocytometer Cell Count CalculatorConvert a manual count from an Improved Neubauer chamber into cells per millilitre, allowing for the number of squares counted and the dilution used.
- Laboratory Temperature ConverterConvert between Celsius, Fahrenheit and kelvin, with the storage and incubation temperatures a laboratory actually runs on and why a few degrees of freezer drift matters.
- mEq to mmol to mg ConverterConvert milliequivalents to millimoles and to milligrams for any ion, using its atomic or molecular weight and its valence — the two numbers the conversion cannot be done without.
- Molarity CalculatorCalculate the molar concentration of a solution from the mass weighed out, the formula weight on the bottle and the final volume.
- Normality to Molarity ConverterConvert an old reagent label in normality to molarity in mol/L — once you have decided how many equivalents the compound supplies in the reaction you are using it for.
- Parts Per Million (ppm) ConverterConvert between ppm, ppb, mg/L, µg/mL, µg/L and per cent — and see where the familiar equivalence of ppm with mg/L stops being true.
- Percent Solution CalculatorWork out the percentage strength of a solution as % w/v, % v/v or % w/w — three conventions that share a symbol and mean different things.
- Pipette Calibration Gravimetric CalculatorConvert a weighed mass of water into a delivered volume with the ISO 8655 Z factor, and read off the systematic error against the pipette's nominal volume.
- Pressure Unit Converter for Lab and Clinical UseConvert mmHg, kPa, cmH2O, atmospheres, bar and psi through the pascal, with the exact definitions and the blood gas unit split that makes the number meaningless on its own.
- Serial Dilution CalculatorFind the concentration at the end of a serial dilution series, and see how quickly the total dilution — and the accumulated pipetting error — grows with each step.
- Solution Osmolarity CalculatorCalculate the theoretical osmolarity of a solution you are making up, from the millimolar concentration of each solute and the number of particles it dissociates into — and see why an osmometer will read lower.
- Universal Mass to Molar Unit ConverterConvert mg/dL, mg/L, µg/mL, g/L and g/dL to mmol/L for any analyte, by entering its molecular weight rather than looking up a factor. The arithmetic is one line; the two places it goes wrong — urea against BUN, and triglycerides — are the reason this page is longer than the formula.
- Universal ng/mL to pmol/L ConverterConvert ng/mL, µg/L, pg/mL, ng/dL and ng/L to pmol/L for any analyte from its molecular weight. For a small peptide the answer is exact. For a glycoprotein there is no single molecular weight to enter, and for a hormone standardised in international units there is no molar conversion at all — which is most of what this page is about.
- Universal µg/dL to nmol/L ConverterConvert µg/dL, ng/mL, µg/L, µg/mL and mg/dL to nmol/L for any analyte by entering its molecular weight. This is the ladder steroids and fat-soluble vitamins are reported on, and the trap is not the arithmetic — it is that testosterone is printed in ng/dL and vitamin D in ng/mL, a hundredfold apart from each other.