Count the total number of bonding electrons
Count the total number of antibonding electrons
Use the formula: Bond order = (Bonding electrons − Antibonding electrons) / 2
For Lewis structures, use the formula: Bond order = Number of bonds between two atoms
For resonance structures, average the bond orders of all valid structures
For molecular orbital theory, fill electrons into molecular orbitals before calculating
For single, double, and triple bonds, bond order is 1, 2, and 3 respectively
For fractional bond order, use the average value from resonance or molecular orbital calculations