1. While in the Budget Record, go to Tools>Options>Records>Budget Management
2. In the Validate row by row field, change Yes to No
3. Click Apply
4. Click OK
5. Save and close the Budget record 
6. Reopen the budget record
7. Enter account numbers and their total budget amounts
8. Once all the total budget amounts are entered, click Edit>Select All*
9. With all rows/accounts highlighted, click Distribute Total on the action bar
10. The system distributes the total amount entered in the Total column evenly across all periods

*If you do not want to highlight all accounts, you can highlight sections of multiple accounts by following the steps below after following steps 1-7 above:
1. click in the box to the left of the first line of  the section of accounts you want to highlight 
2. Press the Shift key on your keyboard
3. Click in the box to the left of the last line of the section you want to highlight
4. Click Distribute Total on the action bar
5. The system distributes the total amount entered in the Total column evenly across all periods

Note: only 100 account budgets can be distributed at once