Apples to Apples Interactive Calculator Step 1. Verify that your local gas utility company is correctly selected below, if not please select your company. Duke Energy Ohio Columbia Gas of Ohio Dominion East Ohio Vectren Energy Delivery of Ohio Step 2. Enter a supplier base rate from the Apples to Apples chart Supplier Base Rate column or supplier literature. Step 3. Enter your annual gas usage (provided on your monthly bill). per year Note: Your supplier base rate and annual gas usage will be based on either hundred cubic feet (ccf) or thousand cubic feet (mcf) units, depending on who your local gas company is. Once you input the supplier gas rate and your annual usage into the Interactive Calculator and hit the CALCULATE button, the results will reflect the correct units, in either ccf or mcf. Step 4. Enter your county sales tax rate. To obtain, call the Ohio Department of Taxation at (614) 466-7351, or access the Ohio Department of Taxation's online county tax map). % Step 5. Click calculate. Complete all information above and use the Calculate button to see the results.