To match medium oak cabinets, you will first need to know what is meant by medium oak. A medium tone white oak, for example, may range from a golden yellow to a light amber hue, while medium red oak will have a decidedly redder colour. English oak typically has a brown hue, which can range from pale beige to rich mocha.
Matching paint to cabinets can be handled in one of two ways. You can choose a tone that is closest to your wood for a monochromatic effect, or go for contrast. While it may seem practical to take a drawer or door to the paint store to choose colours, this is only the first step. The lighting is critical. Select a few colours to try by comparing the wood tone to the samples, then take the samples home to see them in the light in which they will be viewed for a true test. When going for contrast, use a colour wheel and select colours opposite the tone of your medium oak to complement it. You can go several shades lighter or darker. Paint a test patch before committing to the whole room.
Most hardwood and laminate floors are available in a wide variety of colours, and it may be possible to find an almost exact match for your cabinets. This prevents clashing but may not be the best option. While staying with the oak grain presents a continuous grain pattern and appearance, try going a few shades darker to create more visual interest. A darker floor with lighter cabinets will tend to draw the eye up, making your kitchen visually larger. This can also be done with brown stone tile or other flooring, such as vinyl, or stained concrete.
Medium oak is dark enough to have some visual weight to it. A slightly darker hue on your worktops will help to cap off the lower cabinets, while not creating a glaring contrast. Here again, choose a tone that is similar to the oak or go to the colour wheel for a contrasting, yet complementary, shade that can brighten up your kitchen with a pop of colour. Most worktop materials are available in a range of colours, but for the most variety, laminates are your best bet. They are also one of the most affordable options.
If you are working to combine new woodwork or unfinished furniture with your oak cabinets, an exact match should be made or a completely contrasting colour chosen. When two slightly different wood stain colours are set side by side, unless the difference is negligible it will be apparent and glaringly so. Most paint stores will be able to custom-tint stain for you from your existing cabinet colour to use on mouldings or furniture. Take a cabinet door with you to use as a reference and choose a reputable professional paint shop for best results.