ðə kjˈɛldɑːl mˈɛθəd ɔːɹ kjˈɛldɑːl daɪdʒˈɛstʃən ɪn ˌænɐlˈɪɾɪkəl kˈɛmɪstɹi ɪz ɐ mˈɛθəd fɚðə kwˈɔntᵻtˌeɪɾɪv dɪtˌɜːmᵻnˈeɪʃən ʌv nˈaɪtɹədʒən kəntˈeɪnd ɪn ɔːɹɡˈænɪk sˈʌbstənsᵻz plˈʌs ðə nˈaɪtɹədʒən kəntˈeɪnd ɪnðɪ ˌɪnoːɹɡˈænɪk kˈɑːmpaʊndz æmˈoʊniə ænd æmˈoʊniəm ˌɛnˈeɪtʃ θɹˈiː slˈæʃ ˌɛnˈeɪtʃ fˈoːɹ plˈʌs.
The Kjeldahl method or Kjeldahl digestion () in analytical chemistry is a method for the quantitative determination of nitrogen contained in organic substances plus the nitrogen contained in the inorganic compounds ammonia and ammonium (NH3/NH4+).