The firm said the practice brings in £65 for every car and £21 for every home.
Other major insurers such as Aviva do not break out how much they are pocketing in their annual accounts.
Aviva boss Mark Wilson told the Mail this was because the amount is very small.
Finance expert Justin Modray, of advice firm Candid Money, said consumers who sign up for insurance online are sitting ducks.
Insurers can lure these customers in with a rock-bottom basic premium, without showing whether their add-on costs are competitive or not.
Esure said: ‘Instalment income has risen simply as a result of the company selling more policies and the higher average premiums being seen across the industry.
Direct Line said it does not charge fees to amend policies, and the charge for paying by monthly instalments is communicated clearly to customers when they receive a quote.