Amino Acid Calculator

Peptide Property Calculator

Peptide Sequence

Molecular Weight ($\text{g/mol}$)

Isoelectric Point (pI)

Net Charge at pH 7.4

Molar Absorbance ($\text{M}^{-1}\text{cm}^{-1}$)

Ionizable Groups and pKa Values
Group	Count	pKa Value	Charge at pH 7.4
N-terminus ($\text{NH}_3^+$)	1	9.69	1.00
C-terminus ($\text{COO}^-$)	1	2.34	-1.00
Arginine (R)	0	12.48	0.00
Histidine (H)	1	6.00	0.96
Lysine (K)	0	10.53	0.00
Aspartic Acid (D)	0	3.86	0.00
Glutamic Acid (E)	0	4.25	0.00
Cysteine (C)	0	8.18	0.00
Tyrosine (Y)	0	10.07	0.00

Enter Peptide Sequence (1-letter code, e.g., GSHK):

Target pH for Net Charge Calculation:

Note: Molecular weight calculation subtracts the mass of one water molecule ($\text{H}_2\text{O}$) for each peptide bond formed.