Paint Mixing Ratio Calculator

Why Ratios Matter?

When mixing custom colours, always record the exact ratio used. Mixing 'a bit of blue and a bit more white' will never reproduce exactly — ratios like 8:1 (white:blue) let you accurately remake the same colour in any batch size.

What should I know about Keeping Records?

Note: the brand and product line of each paint, the exact colour names and codes, the ratio, and the batch size. Store a small test card with the dried paint alongside your notes. Even a 10% variation in ratio can produce noticeably different results.

What's the key thing to understand about Colour Theory Basics?

Adding white (tinting lighter) changes value but can shift the hue. Adding complementary colours dulls a tone. Small amounts of dark colours dramatically change lighter ones — add dark to light, not light to dark. Start with less tint than you think — it's easier to add than remove.

What should I know about Light, Colour and Room Feel?

Paint colour interacts with natural light in ways that change how a mixed colour actually looks once it's on the wall versus in a tester pot. North-facing rooms get cool, flat, consistent light all day, which makes colours look slightly duller and cooler than expected — warm colours (creams, warm greys, soft yellows) usually compensate well. South-facing rooms get warm, strong light that can wash out pale colours and intensify saturated ones, so a colour that looks subtle on a north wall can look much bolder on a south-facing one. Artificial lighting matters too: warm LED bulbs (2700-3000K) enhance reds, oranges and yellows but can make blues and greens look slightly muddy; cool LED bulbs (4000K+) do the reverse. Always test a mixed colour on the actual wall, in the room, at different times of day, before committing to a full tin — a colour that looks perfect on a sunny afternoon can look completely different under evening artificial light.

What should I know about Undertones in Paint Mixing?

When mixing custom paint colours using tint ratios, it helps to understand that most white or neutral base paints aren't perfectly neutral — they carry a subtle undertone, a warm yellow or cream cast, or a cool blue or grey cast, that will influence every colour mixed from that base. The same tint ratio applied to a warm-based white versus a cool-based white can produce visibly different final colours, even though the ratio of tints is identical, because the base itself is shifting the result. This is one reason professional decorators and paint-matching services always ask which base product is being used before confirming a formula — a colour mixed in one manufacturer's base won't necessarily match the same recipe mixed in a different brand's base, since their underlying undertones differ. If you're trying to match an existing colour, such as a feature wall you want to replicate elsewhere, it's worth testing your mixed ratio on a small sample first and checking it against the original in the same lighting conditions, rather than assuming the ratio alone guarantees an identical match across different paint bases or batches.

What do I need to know about Paint Finish and Perceived Colour?

The same mixed colour will look noticeably different depending on the paint's finish or sheen level, which is worth considering alongside the colour ratio itself. Matt and flat finishes absorb more light and tend to make a colour appear slightly darker and more muted, while also being more forgiving on uneven walls since they don't highlight surface imperfections. Satin, eggshell and semi-gloss finishes reflect more light, which can make the same mixed colour appear brighter or more saturated than the matt version of the identical formula, and they're more durable and wipeable, making them a common choice for kitchens, bathrooms and woodwork. Because of this, it's good practice to mix and test a colour ratio in the actual finish intended for the final job, not a different finish, since a colour approved as a matt sample can look surprisingly different once rolled onto a wall in satin or eggshell. It's also worth testing on an actual offcut of the surface being painted, or a large patch directly on the wall, and viewing it at different times of day, since daylight, warm artificial lighting and cool LED lighting can each shift how a mixed colour reads in the finished room.

How Should You Properly Test Paint Colours Before Committing?

A small swatch on a paint chart or even a tester pot painted directly onto the wall can be misleading, because paint colour perception changes significantly with lighting, surrounding colours, and the sheer scale of a full wall versus a small sample. The most reliable testing method is to paint a reasonably large sample — at least A3 size, ideally larger — onto a piece of card or lining paper rather than directly onto the wall, which allows it to be moved around the room and viewed against different walls and in different light without needing to repaint if the colour doesn't work. Viewing the sample at multiple times of day matters considerably: natural daylight (especially north-facing light, which tends to be cooler and more blue, versus south-facing light, which is warmer) and artificial lighting in the evening can make the same paint colour look noticeably different, so a colour that looks perfect at midday can look quite different under evening lamp light. It's also worth viewing the sample against the room's existing fixed elements — flooring, existing furniture, curtains — rather than in isolation, since paint colour is always perceived in context rather than as a standalone swatch. Finally, remember that a large expanse of colour on a wall reads more intensely than a small sample, so a colour that looks pleasantly bold on a test card can feel overwhelming across an entire room — when in doubt, many professional decorators suggest going a shade or two lighter than the sample suggests feels right.

What do I need to know about Calculating Tint Ratios for a Target Shade Strength?

Tinting percentage describes what fraction of a mixed batch is full-strength colourant versus white (or neutral) base — and because paint mixing machines and hand-mixing recipes both work in simple part-ratios, converting a target percentage into a mixing ratio is just basic arithmetic once set up correctly. If x parts of full-strength tint colour are mixed into a batch totalling T parts, the tint strength is x ÷ T. Worked example: to achieve a 35% tint strength in a 10-part batch — x ÷ 10 = 0.35 x = 3.5 parts tint colour Remaining base = 10 − 3.5 = 6.5 parts white/neutral base So a 35% tint batch is mixed at a ratio of 3.5 parts tint colourant to 6.5 parts base — commonly rounded to something practical like 70 ml tint to 130 ml base for a 200 ml test pot, or scaled up proportionally for a full 2.5-litre tin (875 ml tint to 1,625 ml base). The same logic works in reverse: if you've already got a favourite custom mix and want to recreate it at a different batch size, measure the ratio of tint to base in your original batch, then apply that same ratio (not the same absolute volumes) to the new total volume.

What do I need to know about Paint Sheen Levels and Light Reflectance?

Beyond colour itself, the sheen level you choose changes how a colour actually looks on the wall, because glossier finishes reflect more light back at the viewer — which can make the same tin of paint look noticeably lighter or more saturated depending on the finish.

These are typical, approximate ranges — exact LRV depends on the base colour as much as the finish, since a dark matt colour can easily have a lower LRV than a pale satin one. The practical takeaway is to always view a tester swatch in the actual sheen you plan to use, not just the colour chip or a different finish's sample pot, because the same pigment load can look meaningfully different once it's reflecting light at a semi-gloss or gloss level rather than matt.