# RNA Concentration Calculator (A260, 1 OD = 40 µg/mL) Beer–Lambert RNA quantitation: c = A260 × dilution factor × 40 / path length, plus ng/µL, total yield, a 0.1–1.5 linear-range check, and the RNA OD260/280 ≈ 2.0 purity reminder. Derived from Marmur & Doty, Sambrook & Russell, Manchester 1995, Thermo Fisher NanoDrop notes. Educational use only. > Canonical page: https://elysiatools.com/en/tools/rna-concentration-a260 - **Category:** Education - **Keywords:** rna concentration, a260 absorbance rna, od260 rna quantitation, 1 od = 40 µg/ml rna, rna yield calculator, nanodrop rna, spectrophotometer rna, total rna quantification, ng/µl rna, mrna concentration, molecular biology, lab calculator ## Overview The RNA Concentration Calculator estimates RNA concentration from A260 absorbance using c = A260 × dilution factor × 40 ÷ path length. It reports µg/mL, ng/µL, optional total yield, and whether the absorbance is within the approximate 0.1–1.5 linear range. Educational use only. ## Inputs - **A260 Absorbance** (number): Measured absorbance of the (diluted) sample at 260 nm, blanked against the RNase-free elution buffer. - **Dilution Factor** (number): Sample-to-total dilution before measurement (1 = measured undiluted). - **Path Length (cm)** (number): Cuvette path length (1 cm standard; microvolume readers may use 0.1–1 cm). - **Sample Volume (µL, optional)** (number): Total elution volume in µL; enter 0 to skip the total-yield calculation. - **Decimal Places** (number) ## When to use - Estimate RNA concentration from a blanked A260 measurement. - Convert a diluted spectrophotometer reading into the concentration of the original sample. - Calculate total RNA yield when the elution volume is known. ## How it works - Enter the measured A260 absorbance, dilution factor, and optical path length in centimeters. - The calculator applies the RNA conversion factor of 40 µg/mL per OD at 260 nm. - It converts the result to ng/µL and calculates total micrograms when a sample volume is provided. - It checks whether A260 is within the approximate 0.1–1.5 linear range and reminds users that pure RNA typically has an OD260/280 near 2.0. ## Use cases - Quantifying total RNA after extraction or elution. - Adjusting concentrations for downstream molecular biology experiments. - Checking whether an A260 measurement falls within the calculator's approximate linear range. ## Frequently asked questions ### What formula does the calculator use? It uses concentration = A260 × dilution factor × 40 ÷ path length in cm. ### Why is the RNA factor 40? For this calculation, 1 OD at 260 nm is treated as 40 µg/mL of RNA. ### How is ng/µL related to µg/mL? The values are numerically equal: 1 µg/mL equals 1 ng/µL. ### When should I enter a sample volume? Enter the total elution volume in µL when you want the calculator to estimate total RNA yield. ### What does a reading outside 0.1–1.5 mean? It is outside the approximate linear range; low readings may be less reliable, while high readings may require appropriate dilution. ## Related tools - [DNA Concentration Calculator (A260 Absorbance)](https://elysiatools.com/en/tools/dna-concentration-a260): Beer–Lambert DNA quantitation: c = A260 × dilution factor × K / path length with 1 OD = 50 µg/mL dsDNA or 33 µg/mL ssDNA, plus ng/µL, total yield, and a 0.1–1.5 linear-range check. Derived from Marmur & Doty, Sambrook & Russell, Thermo Fisher NanoDrop notes. Educational use only. - [OD260/230 Nucleic Acid Purity Ratio Calculator](https://elysiatools.com/en/tools/od260-230-ratio): Check salt/organic-solvent contamination with A260/A230 (pure 2.0–2.2; below 2.0 = guanidinium/phenol/EDTA/salt carryover from TRIzol or columns), with an optional A260/280 cross-check. Derived from Thermo Fisher T042, Sambrook & Russell, Manchester 1995. Educational use only. - [OD260/280 Nucleic Acid Purity Ratio Calculator](https://elysiatools.com/en/tools/od260-280-ratio): Judge DNA/RNA purity from A260/A280 (pure DNA ~1.8, pure RNA ~2.0; low = protein/phenol contamination, DNA > 2.0 = RNA contamination) plus the optional A260/A230 secondary check. Derived from Manchester 1995, Sambrook & Russell, Thermo Fisher T042. Educational use only. - [BCA Assay Calculator (Protein Standard Curve)](https://elysiatools.com/en/tools/bca-assay-calculator): Least-squares A562 curve fit, back-calculated unknowns with dilution factor, extrapolation flags, and detergent/reducing-agent compatibility notes. Educational use only. - [Bradford Assay Calculator (BSA Standard Curve)](https://elysiatools.com/en/tools/bradford-assay-calculator): Least-squares BSA curve, back-calculated unknowns with dilution factor, extrapolation flags, and protein-specific dye-response caveats. Educational use only. - [Markdown Link Extractor](https://elysiatools.com/en/tools/markdown-link-extractor): Extract inline links, reference links, and bare URLs from Markdown documents with basic syntax validation - [Blood Gas Acid-Base Interpretation (AG / ΔAG)](https://elysiatools.com/en/tools/blood-gas-anion-gap): Complete ABG analysis: pH, primary disorder, compensation (Winter's formula), anion gap ± albumin correction, delta ratio for mixed disorder detection. Derived from Emmett 2016, Kraut 2007, Rastegar 2007, LITFL, MDCalc, and Adrogué 1998. Not medical advice. - [CURB-65 vs PSI vs SMART-COP (Pneumonia Severity Comparison)](https://elysiatools.com/en/tools/curb-65-vs-pneumonia-severity): Compare three pneumonia severity scores side-by-side from one set of inputs to support concordance reading. CURB-65 (0-5: Confusion, Urea, RR, BP, age ≥65) — quick bedside triage; PSI/PORT (Fine 1997, 5 risk classes) — the most accurate mortality stratification, more complex; SMART-COP (0-10, 2 points each for SBP <90 and hypoxia, 1 point each for multilobar CXR, albumin <3.5, RR ≥25, tachycardia ≥125, confusion, pH <7.35) — predicts need for ICU respiratory/vasopressor support. Each score has a different focus: CURB-65 is fast; PSI is more precise; SMART-COP identifies who needs ICU. The tool reports each score's total/category/interpretation and an agreement analysis (whether all three point to outpatient/admission/ICU). When scores disagree, favor the more conservative disposition. Derived from Lim 2003, Fine 1997, Charles 2008. Not medical advice. ## Samples - [Web Image Processing Python Samples](https://elysiatools.com/en/samples/web-image-processing-python): Web Python image processing examples using PIL/Pillow including reading, saving, resizing, and format conversion - [Android Image Processing Java Samples](https://elysiatools.com/en/samples/android-image-processing-java): Android Java image processing examples including reading/saving images, scaling, and format conversion - [Android Image Processing Kotlin Samples](https://elysiatools.com/en/samples/android-image-processing-kotlin): Android Kotlin image processing examples including reading/saving images, scaling, and format conversion - [Web Image Processing Rust Samples](https://elysiatools.com/en/samples/web-image-processing-rust): Web Rust image processing examples including image read/save, scaling, and format conversion ## Related content - [Audio Encoding and Format Conversion Tools](https://elysiatools.com/en/hubs/audio-convert): Compare audio format conversion, bitrate changes, sample-rate conversion, codec swaps, and export tools in one hub for delivery and archive workflows. - [Image Format Conversion and Animated Export Tools](https://elysiatools.com/en/hubs/image-convert): Compare image format converters for JPG, PNG, GIF, AVIF, WebP, TIFF, ICO, base64, and animation-friendly exports in one hub. - [JSON Interchange and Format Translation Tools](https://elysiatools.com/en/hubs/json-convert): Compare JSON conversion tools for CSV, YAML, TOML, GraphQL, XML, Markdown, Excel, BSON, EDN, and related structured formats in one hub. - [Color Space Conversion Tools for Web and Print](https://elysiatools.com/en/hubs/design-convert): Curated tools for web-to-print color space conversion in one hub.