Protein UV A280 Absorbance to mg/mL & Micromolar Concentration Calculator

Convert NanoDrop / cuvette A280 readings into mg/mL and μM protein concentration.

Protein Concentration (mg/mL)
1.42 mg/mL
Micromolar Concentration (μM) 27.38 μM
Concentration in μg/μL 1.42 μg/μL
Absorbance of 1 mg/mL (A₂₈₀^0.1%) 0.81 AU
Inputs
AU
Measured 280 nm absorbance (1.0 cm pathlength equivalent).
M⁻¹·cm⁻¹
Protein molar extinction coefficient ε₂₈₀ (M⁻¹·cm⁻¹).
kDa
Protein molecular weight in kilodaltons (kDa).
Results & Graph
Protein Concentration (mg/mL)
1.42 mg/mL
Micromolar Concentration (μM)
27.38 μM
Concentration in μg/μL
1.42 μg/μL
Absorbance of 1 mg/mL (A₂₈₀^0.1%)
0.81 AU

Protein Concentration (mg/mL)

Graph 1 • Absorbance280 Nm Sensitivity Recalculates the domain equation across 50% to 150% of the primary input while holding other parameters constant.
0 mg/mL 1.2 mg/mL 2.3 mg/mL 50%: 0.71 mg/mL 0.7 50% 75%: 1.07 mg/mL 1.1 75% 100%: 1.42 mg/mL 1.4 100% 125%: 1.78 mg/mL 1.8 125% 150%: 2.14 mg/mL 2.1 150%
Graph 2 • Primary & Supporting Metric Comparison Compares the primary output alongside supporting domain benchmarks.
Protein Concentration (mg/mL) 1.42 mg/mL Micromolar Concentration (μM) 27.38 μM Concentration in μg/μL 1.42 μg/μL Absorbance of 1 mg/mL (A₂₈₀^0.1%) 0.81 AU
Graph 3 • Exact Output Table & Units Displays each calculated output in its exact domain unit.
Protein Concentration (mg/mL)1.42 mg/mLMicromolar Concentration (μM)27.38 μMConcentration in μg/μL1.42 μg/μLAbsorbance of 1 mg/mL (A₂₈₀^0.1%)0.81 AU
Summary: At A₂₈₀ = 1.15 AU (ε=42,000 M⁻¹·cm⁻¹, MW=52 kDa), protein concentration is 1.42 mg/mL (27.38 μM).
Summary: At A₂₈₀ = 1.15 AU (ε=42,000 M⁻¹·cm⁻¹, MW=52 kDa), protein concentration is 1.42 mg/mL (27.38 μM).
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Formula & Mathematical Methodology: Protein A280 Concentration Reference Equation

MolarityM = A₂₈₀ / (ε₂₈₀ × lcm)
Concentrationmg/mL = MolarityM × (MWkDa × 1000)
Molarity_M = A₂₈₀ / (ε₂₈₀ × l_cm); Concentration_mg/mL = Molarity_M × (MW_kDa × 1000)
  • absorbance280Nm: Absorbance280 Nm (AU)
  • extinctionCoeffM1Cm1: Extinction Coeff M1 Cm1 (M⁻¹·cm⁻¹)
  • molecularWeightKda: Molecular Weight Kda (kDa)

Rounding: Laboratory and clinical equations retain full floating-point precision and round displayed results to 2 decimal places.

Worked Example: Reference Calculation: Protein A280 Concentration

Convert NanoDrop / cuvette A280 readings into mg/mL and μM protein concentration.

  1. Enter the reagent concentrations, assay readings, or clinical laboratory parameters.
  2. Compute the standard formula: Molarity_M = A₂₈₀ / (ε₂₈₀ × l_cm); Concentration_mg/mL = Molarity_M × (MW_kDa × 1000).
  3. Review the primary result, supporting reference intervals, and 3 SVG visualizations.
Result: Evaluates Protein A280 Concentration via Molarity_M = A₂₈₀ / (ε₂₈₀ × l_cm); Concentration_mg/mL = Molarity_M × (MW_kDa × 1000).

Frequently Asked Questions

What formula is used by the Protein UV A280 Absorbance to mg/mL & Micromolar Concentration Calculator?

It computes Molarity_M = A₂₈₀ / (ε₂₈₀ × l_cm); Concentration_mg/mL = Molarity_M × (MW_kDa × 1000) and plots three custom SVG graphs showing parameter sensitivity and component breakdowns.

Can I compare different reagent dilutions or lab scenarios side by side?

Yes. Use the "Compare (0/3)" button to pin up to 3 scenarios side by side.

Are entered values stored on any server?

No. Every calculation runs 100% locally in your browser.

Science & Engineering · Molecular Biology & Genetics

Protein UV A280 Absorbance to mg/mL & Micromolar Concentration Calculator: inputs, method, and how to read the result

Convert NanoDrop / cuvette A280 readings into mg/mL and μM protein concentration.

Choose inputs for the case you are checking

The defaults are illustrative. Replace them with values for your case and keep the units shown beside each field.

  • Absorbance280 Nm: Measured 280 nm absorbance (1.0 cm pathlength equivalent).
  • Extinction Coeff M1 Cm1: Protein molar extinction coefficient ε₂₈₀ (M⁻¹·cm⁻¹).
  • Molecular Weight Kda: Protein molecular weight in kilodaltons (kDa).

What the calculation includes

With the default values shown, Protein Concentration (mg/mL) is 1.42 mg/mL. The calculation follows Protein A280 Concentration Reference Equation; the formula and variable definitions above show how the inputs combine.

One-input check: With the other defaults held constant, changing Absorbance280 Nm from 1.15 AU to 1.26 AU changes Protein Concentration (mg/mL) from 1.42 mg/mL to 1.56 mg/mL. This is a comparison inside the calculator's stated model, not a prediction.

Where to use caution

  • Uses standard IUPAC atomic weights, 25°C (298.15 K) reference thermodynamics, and published clinical literature equations.
  • Educational and laboratory reference tool only; clinical scoring calculators do not replace professional medical judgment or institutional protocols.

Scope: IUPAC / NIH Laboratory & Clinical Reference Standard Check the assumptions and limitations against your situation before relying on the estimate.

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