Weight Based Shipping

- Check your store's default weight class and currency settings (in  Settings > Config default). Make sure they're set to what you want.

- Check your store's weight class values (in  Settings >  Weight Management). Make sure your default class is set to 1.0000, and the others are set to appropriate conversion values. For example, if your default weight class is kg, then you would set its value to 1.0000, and set the value for grams to 1000.

- Check your store's default currency value (in Settings  > Config default). Make sure your default currency value is set to 1.0000.

- Since your default weight class is used in Weight Based Shipping, make sure your rates are using the appropriate values based on this weight class. So if you're using the rates 1:5.00, 2:7.00, etc. with a default weight class of kg, that means, "Up to 1 kg charge 5.00, up to 2 kg charge 7.00, etc."

- Check your product weights and weight classes, and make sure they're set to what you want.