DEF consumption estimator

DEF use runs about 2–3% of diesel burned. Enter your driving and get a yearly estimate.

Miles driven per year Fuel economy (mpg) DEF rate (% of fuel) — 2.5 is typical DEF price per gallon ($)

Keep it fresh

DEF goes bad. It lasts about a year in a cool garage, less in heat. Do not stockpile cases in a hot shed. If your truck throws a reductant quality code, old DEF is the first suspect — drain and refill with fresh fluid before you spend money on sensors.