Mass Spectrometry Calculator

Calculate molecular mass from m/z values and charge states

Calculation Mode

Key Equations

M = (m/z × z) - (z × m_adduct)

m/z = (M + z × m_adduct) / z

Calculated Mass

1997.99 Da

1.998 kDa

Analysis

Monoisotopic Mass1997.9854 Da
Est. Residues~18 aa
m/z at z=21000.00

Charge State Distribution

z=1: 1998.99
z=2: 1000.00
z=3: 667.00
z=4: 500.50
z=5: 400.60
z=6: 334.00
z=7: 286.43
z=8: 250.76
z=9: 223.01
z=10: 200.81

About Mass Spectrometry Calculations

Mass spectrometry measures the mass-to-charge ratio (m/z) of ions. Key concepts:

  • m/z: Mass-to-charge ratio measured by the mass spectrometer
  • Charge state: Number of charges (protons) on the ion
  • ESI: Electrospray ionization produces multiply charged ions
  • MALDI: Matrix-assisted laser desorption ionization typically produces singly charged ions
  • Deconvolution: Process of determining molecular mass from multiple charge states