Be sure that the vehicle is parked on level ground.
If the engine is running, turn the engine off and wait at least five minutes for the oil to settle.
Pull out the dipstick, wipe it clean with a lint free cloth and fully reinsert it.
Pull the dipstick out again add note the oil level on the dipstick. If the level is between the "Full" and the "Add" marks it is satisfactory. If it is near the "Add" line, add enough oil to bring the level to the "Full" line.
Only use oil that meets the specification of your vehicle's manufacturer. This information is located in the owner's handbook. If you find the engine oil requires more regular topping up, it may be due to the need for servicing.
Consult your TACC member workshop for a service and appraisal of the cause of oil consumption.