{"success":true,"version":"v1","request":{"tool":"get_calculator_schema","calculator_id":"dna-concentration"},"result":{"entity_type":"calculator","id":"dna-concentration","calculator_id":"dna-concentration","canonical_url":"https://tttkmbb.com/science/dna-concentration","name":"DNA / RNA Concentration Calculator","title":"DNA and RNA Concentration Calculator – A260 to ng/µL with 260/280 and 260/230 Purity Ratios","category":"science","category_name":"Biology, Earth & Space","tool_name":"calculate_nucleic_acid_concentration","featured_mcp_tool":false,"description":"Converts an absorbance reading at 260 nm into nucleic acid concentration with the standard factors (dsDNA 50, ssDNA 33, RNA 40, oligonucleotide 33 µg/mL per A260 unit) and a dilution factor, and assesses purity from the A260/A280 and A260/A230 ratios.","use_when":"You measured A260 (and optionally A280, A230) on a spectrophotometer or NanoDrop and need the concentration in µg/mL or ng/µL, the total amount in a sample, or a purity check.","do_not_use_when":"The sample is very dilute or contaminated (fluorometric assays such as PicoGreen are more specific), you need the molar concentration of a specific oligo (requires its extinction coefficient), or the reading is outside the instrument's linear range.","inputs":[{"name":"a260","label":"A260","type":"number","required":true,"min":0,"max":100,"description":"Absorbance at 260 nm for a 1 cm path length (blank-corrected). NanoDrop-type instruments report the 10 mm-equivalent value.","example":0.5},{"name":"dilution_factor","label":"Dilution factor","type":"number","required":false,"default":1,"min":1,"max":1000000,"description":"Dilution of the sample before measuring (1 = measured neat, 10 = 1:9).","example":10},{"name":"nucleic_acid","label":"Nucleic acid type","type":"enum","required":false,"default":"dsdna","values":[{"value":"dsdna","label":"Double-stranded DNA (50 µg/mL per A260)","aliases":["dna","genomic","plasmid"]},{"value":"ssdna","label":"Single-stranded DNA (33 µg/mL per A260)"},{"value":"rna","label":"RNA (40 µg/mL per A260)"},{"value":"oligo","label":"Oligonucleotide, single-stranded (33 µg/mL per A260, approximate)","aliases":["primer","oligonucleotide"]}],"description":"Determines the conversion factor (µg/mL per absorbance unit).","example":"dsdna"},{"name":"a280","label":"A280","type":"number","required":false,"max":100,"exclusive_min":0,"description":"Absorbance at 280 nm; gives the 260/280 ratio (proteins absorb here).","example":0.27},{"name":"a230","label":"A230","type":"number","required":false,"max":100,"exclusive_min":0,"description":"Absorbance at 230 nm; gives the 260/230 ratio (salts, phenol, carbohydrates absorb here).","example":0.25},{"name":"sample_volume_ul","label":"Sample volume","type":"number","unit":"µL","required":false,"max":1000000000,"exclusive_min":0,"description":"Volume of the undiluted sample; gives the total amount in µg.","example":50}],"outputs":[{"name":"concentration_ug_per_ml","label":"Concentration","type":"number","unit":"µg/mL","decimals":2,"description":"a260 × factor × dilution_factor."},{"name":"concentration_ng_per_ul","label":"Concentration (ng/µL)","type":"number","unit":"ng/µL","decimals":2,"description":"Same value: 1 µg/mL = 1 ng/µL."},{"name":"conversion_factor","label":"Factor used","type":"number","unit":"µg/mL per A260","decimals":0,"description":"50 (dsDNA), 33 (ssDNA), 40 (RNA) or 33 (oligo)."},{"name":"ratio_260_280","label":"A260/A280","type":"number","decimals":2,"description":"Purity ratio: ≈1.8 for pure DNA, ≈2.0 for pure RNA (when a280 is given)."},{"name":"ratio_260_230","label":"A260/A230","type":"number","decimals":2,"description":"Purity ratio: 2.0–2.2 expected (when a230 is given)."},{"name":"purity_assessment","label":"Purity assessment","type":"string","decimals":4,"description":"Interpretation of the available ratios."},{"name":"total_amount_ug","label":"Total amount","type":"number","unit":"µg","decimals":3,"description":"concentration_ng_per_ul × sample_volume_ul / 1000 (when the volume is given)."}],"input_schema":{"type":"object","properties":{"a260":{"description":"Absorbance at 260 nm for a 1 cm path length (blank-corrected). NanoDrop-type instruments report the 10 mm-equivalent value.","type":"number","minimum":0,"maximum":100,"examples":[0.5]},"dilution_factor":{"description":"Dilution of the sample before measuring (1 = measured neat, 10 = 1:9).","type":"number","minimum":1,"maximum":1000000,"default":1,"examples":[10]},"nucleic_acid":{"description":"Determines the conversion factor (µg/mL per absorbance unit).","type":"string","enum":["dsdna","ssdna","rna","oligo"],"default":"dsdna","examples":["dsdna"]},"a280":{"description":"Absorbance at 280 nm; gives the 260/280 ratio (proteins absorb here).","type":"number","maximum":100,"exclusiveMinimum":0,"examples":[0.27]},"a230":{"description":"Absorbance at 230 nm; gives the 260/230 ratio (salts, phenol, carbohydrates absorb here).","type":"number","maximum":100,"exclusiveMinimum":0,"examples":[0.25]},"sample_volume_ul":{"description":"Volume of the undiluted sample; gives the total amount in µg. Unit: µL.","type":"number","maximum":1000000000,"exclusiveMinimum":0,"examples":[50],"x-unit":"µL"}},"additionalProperties":false,"required":["a260"]},"output_schema":{"type":"object","properties":{"concentration_ug_per_ml":{"description":"a260 × factor × dilution_factor. Unit: µg/mL.","type":"number","x-unit":"µg/mL"},"concentration_ng_per_ul":{"description":"Same value: 1 µg/mL = 1 ng/µL. Unit: ng/µL.","type":"number","x-unit":"ng/µL"},"conversion_factor":{"description":"50 (dsDNA), 33 (ssDNA), 40 (RNA) or 33 (oligo). Unit: µg/mL per A260.","type":"number","x-unit":"µg/mL per A260"},"ratio_260_280":{"description":"Purity ratio: ≈1.8 for pure DNA, ≈2.0 for pure RNA (when a280 is given).","type":"number"},"ratio_260_230":{"description":"Purity ratio: 2.0–2.2 expected (when a230 is given).","type":"number"},"purity_assessment":{"description":"Interpretation of the available ratios.","type":"string"},"total_amount_ug":{"description":"concentration_ng_per_ul × sample_volume_ul / 1000 (when the volume is given). Unit: µg.","type":"number","x-unit":"µg"}}},"formula":"concentration (µg/mL) = A260 × factor × dilution_factor, factor = 50 (dsDNA), 33 (ssDNA), 40 (RNA), 33 (oligo); ng/µL = µg/mL; total µg = ng/µL × µL / 1000; ratios = A260 / A280 and A260 / A230","method":"Beer–Lambert law with the conventional average extinction factors for a 1 cm path (dsDNA 50, ssDNA 33, RNA 40 µg/mL per absorbance unit at 260 nm); for short oligonucleotides the sequence-specific extinction coefficient is more accurate. Pure DNA has A260/A280 ≈ 1.8 and RNA ≈ 2.0; A260/A230 is expected at 2.0–2.2; lower values indicate contamination (protein or phenol at 280 nm; guanidine, phenol, EDTA or carbohydrates at 230 nm).","sources":[{"name":"Wikipedia – Nucleic acid quantitation","url":"https://en.wikipedia.org/wiki/Nucleic_acid_quantitation","type":"reference","retrieved_at":"2026-09-24"},{"name":"Wikipedia – Beer–Lambert law","url":"https://en.wikipedia.org/wiki/Beer%E2%80%93Lambert_law","type":"reference","retrieved_at":"2026-09-24"}],"freshness":{"type":"static","max_age_seconds":null,"note":"Deterministic formula with fixed constants; results never go stale. Inputs supplied by the caller determine the output."},"examples":[{"name":"dsDNA, A260 0.5 at 1:10 dilution, A280 0.27","inputs":{"a260":0.5,"dilution_factor":10,"nucleic_acid":"dsdna","a280":0.27,"sample_volume_ul":50},"expected":{"concentration_ug_per_ml":250,"concentration_ng_per_ul":250,"conversion_factor":50,"ratio_260_280":1.85,"total_amount_ug":12.5},"url":"https://tttkmbb.com/api/v1/calculate/dna-concentration?a260=0.5&dilution_factor=10&nucleic_acid=dsdna&a280=0.27&sample_volume_ul=50"},{"name":"RNA, A260 1.2 neat, A280 0.6, A230 0.55","inputs":{"a260":1.2,"nucleic_acid":"rna","a280":0.6,"a230":0.55,"sample_volume_ul":50},"expected":{"concentration_ug_per_ml":48,"ratio_260_280":2,"ratio_260_230":2.18,"total_amount_ug":2.4},"url":"https://tttkmbb.com/api/v1/calculate/dna-concentration?a260=1.2&nucleic_acid=rna&a280=0.6&a230=0.55&sample_volume_ul=50"}],"faq":[{"q":"Is ng/µL the same as µg/mL?","a":"Yes: 1 µg/mL = 1,000 ng / 1,000 µL = 1 ng/µL, so the two outputs are always identical."},{"q":"Do I enter the diluted or undiluted volume?","a":"sample_volume_ul is the volume of your original (undiluted) sample; the dilution used only for the measurement is handled by dilution_factor."},{"q":"What if the 260/280 ratio is low?","a":"Values well below 1.8 (DNA) or 2.0 (RNA) usually mean protein or phenol carry-over; note that the ratio is also affected by pH and ionic strength of the blank, and high concentrations of pure DNA can still read slightly below 1.8."}],"tags":["dna concentration","a260","nanodrop","260/280 ratio","rna concentration","ng/ul"],"related":[{"calculator_id":"pcr-primer-tm","reason":"Molecular weight of a primer to convert its mass concentration to molarity."},{"calculator_id":"dilution","reason":"Dilute the sample to a working concentration (C1V1 = C2V2)."},{"calculator_id":"molarity","reason":"Convert a mass concentration to molar concentration with the molecular weight."}],"links":{"html":"https://tttkmbb.com/science/dna-concentration","markdown":"https://tttkmbb.com/science/dna-concentration.md","json":"https://tttkmbb.com/science/dna-concentration.json","api":"https://tttkmbb.com/api/v1/calculate/dna-concentration","schema":"https://tttkmbb.com/api/v1/calculators/dna-concentration","openapi":"https://tttkmbb.com/openapi.json","mcp":"https://tttkmbb.com/mcp"},"version":"v1","updated_at":"2026-09-24"},"timestamp":"2026-09-24T03:44:38Z"}