How to read the dipstick
Park on level ground and switch the engine off. If your manual asks you to check warm, run the engine briefly, then wait the time it specifies so the oil can drain back into the pan. Open the hood, find the dipstick (usually a loop or colored handle), and pull it out.
Wipe the dipstick clean with a lint-free cloth, then push it all the way back in and pull it out again. This second reading is the accurate one. Hold it horizontally and look at the film of oil near the tip. There are two marks, often labeled minimum and maximum or shown as a crosshatched zone. The oil should sit between them. Many vehicles now use an electronic oil reading instead of a dipstick, in which case follow the on-screen procedure in your manual.
Level, color and condition
The level tells you whether to top up. If it sits near or below the lower mark, add oil a little at a time, rechecking between additions, and stop within the marked range. Overfilling can be as harmful as running low, so do not exceed the upper mark. Only ever add the viscosity grade and specification your owner’s manual lists.
Color and feel give a rough sense of condition, not a precise verdict. Fresh oil is amber and translucent; used oil darkens normally as it picks up combustion by-products. Oil that looks milky or has a coffee-colored froth, smells strongly of fuel, or contains gritty particles can point to a problem rather than a simple top-up. In those cases, have a mechanic inspect the engine rather than assuming an oil change alone will fix it.
When checking matters most
Check the level before long journeys, after noticing any oil spots where you park, and at the intervals your manual recommends. If the level keeps dropping between checks, note how much you are adding and over what distance. Steady consumption is worth discussing with a mechanic, because the cause matters more than simply keeping the oil topped up.