What Size Hair Foil Should I Use?

The most common hair foil sizes used by professional colourists are 15×30cm, 15×35cm and 20×40cm. The right size depends on the technique you’re using and the section of hair you’re working with. For most full-head foil work, a 15×35cm foil is the go-to - and our fastest seller at Alex Loves Colour. For balayage, freehand painting and extra-long hair, a wider 20×40cm foil gives you the room you need. And our 15×30cm is the perfect compact option for face-framing highlights and partials.

Choosing the wrong foil size is one of the most common mistakes I see colourists make - and I get it, because when I started out over 12 years ago, I used whatever was handed to me without thinking twice. But once you understand which size to reach for and why, your work gets faster, cleaner and more consistent. Let me walk you through it.

Hair Foil Sizes Explained

Hair foil is measured in width × length (centimetres). The width determines how much hair you can fit across the foil, and the length determines how far down the hair shaft the foil extends. Here’s how each standard size performs in the salon.

15cm × 27cm - Why We Moved Away From the Short Foil

The 15×27cm foil is a size you’ll still see from some brands, and we used to make it ourselves. But here’s what we noticed: when colourists go to place a foil, they fold the top of the foil over and slide their tail comb underneath to position it against the scalp. That fold at the top eats into a few centimetres of usable length. On a 27cm foil, you’re already losing working area before you’ve even started applying product - especially on anything past chin length.

So we made a decision. We increased our smallest size by 3cm to 15×30cm, giving colourists that extra room for the tail comb fold without jumping up to a much larger foil. It’s a small change on paper, but it makes a real difference behind the chair. Our smallest size at Alex Loves Colour is now the 15×30cm.

15cm × 30cm — Our Smallest Size (and Why It Exists)

The 15×30cm is our smallest foil at Alex Loves Colour, and it exists because of the lesson we learned from the 15×27cm. Those extra 3cm give you proper room for the tail comb fold at the top while still keeping the foil compact enough for precision work. It comes in silver with 500 sheets per box - making it incredible value for high-volume salons. It’s long enough for most medium-length hair, but not so large that you’re wasting material on shorter sections.

This is a popular choice for colourists who do a lot of half-head highlights, face-framing, partials and men’s colour work. If your client base is predominantly short to medium-length hair, this is the size to stock alongside your 15×35cm.

Best for:

•         Face-framing highlights and money pieces

•         Half-head and partial foil services

•         Men’s colour services and short to medium hair

•         Babylights and fine weave techniques

15cm × 35cm - Our Fastest Seller

If you could only stock one size, this would be it - and our sales numbers prove it. The 15cm ×35cm is our fastest-selling foil at Alex Loves Colour, and for good reason: it falls right in between our smallest (15cm ×30cm) and our extra-wide (20cm ×40cm), making it the perfect all-rounder for the majority of colour services.

At 35cm long, it comfortably handles full-head foil work on most hair lengths - from bobs through to clients with longer hair. Even after folding the top over your tail comb for placement, you’ve still got plenty of usable length. And here’s the kicker: you get 300 sheets per box compared to only 200 sheets in the 20cm ×40cm extra-wide foil. That’s 100 extra sheets, which means more services per box and a lower cost per client. For most colourists, the 15×35cm handles long hair just fine - so unless you’re regularly working with waist-length hair or doing a lot of balayage, this is the size that gives you the best value.

This is also the size where you get all the fun. Our Essentials collection (Bohemian, Deep, Clay and Obsidian) all come in 15cm ×35cm with 300 sheets per box. But it’s also the size that gets all the prints - Care Bears, Tokidoki, all four Essentials colours, and another awesome licensed print coming soon. If you want to bring personality and colour to your colour bar, this is the size that does it. It’s the workhorse of any salon.

Best for:

•         Full-head foil highlights

•         T-section and three-quarter head services

•         Long bobs (lobs) through to long hair

•         Tint-back and colour correction foil work

20cm × 40cm — The Wide Foil

This is the foil you reach for when you need more real estate. At 20cm wide (compared to the standard 15cm), it gives you an extra 5cm of width - which makes a huge difference for balayage, freehand painting, and working with thick or extra-long hair. The 40cm length means it extends further down the hair shaft, so you’re not running out of foil on clients with waist-length hair. Our 20cm ×40cm comes in silver with 200 sheets per box (compared to 300 in our 15cm ×35cm).

Wide foils are also brilliant for open-air techniques where you want the foil to act as a barrier between sections without needing to fold tightly. Some colourists use them exclusively for balayage - once you try a 20cm ×40cm for freehand work, it’s hard to go back.

Best for:

•         Balayage and freehand painting techniques

•         Extra-long or very thick hair

•         Open-air foiling and meche work

•         Full-head foils on clients with waist-length hair or longer

Does the Type of Foil Matter as Much as the Size?

Absolutely. Size gets you in the right ballpark, but the quality and texture of the foil determines how it performs in your hands. Cheap, thin foils tear during application, slip out of place and transfer heat unevenly. That’s why every Alex Loves Colour foil features an embossed nano-dot texture that grips the hair and holds product in place - meaning less slipping, less bleeding and cleaner results.

Our foils are also pre-cut and come in a pop-up dispenser - just pull a sheet out like a tissue box and you’re ready to go. Every box is 100% recyclable and each foil box is perforated for easy access. These details might sound small, but across a full day of colour services, they add up to faster application, less fatigue and a more consistent result.

Common Mistakes When Choosing Hair Foil Size

Using one size for everything. It’s tempting to bulk-buy one size and use it across the board, but you’ll end up with wasted material on short sections and cramped foils on long hair. Stock at least two sizes — a 15cm ×35cm for standard work and either a 15cm ×30cm for partials or a 20cm ×40cm for balayage depending on your client base.

Going too small for balayage. If you’re doing freehand work with a 15cm ×30cm foil, you’re fighting the foil. Switch to a 20cm ×40cm and give yourself the space to paint freely.

Ignoring foil width. Most colourists focus on length, but the width matters just as much. A 20cm-wide foil lets you take wider sections, which speeds up application time on thick hair.

Frequently Asked Questions

What size hair foil is best for highlights/balayage?

For most highlight and balayage services, a 15cm ×35cm foil is the best all-round choice. It’s long enough to handle full-head foils on most hair lengths and is the industry standard used by professional colourists worldwide. If you’re doing a lot of freehand balayage on extra-long or very thick hair, step up to the 20cm ×40cm for extra width and length - but for the majority of highlight and balayage clients, the 15cm ×35cm does the job beautifully.

Can I use the same foil size for every client?

You can, but you shouldn’t. Using a foil that’s too large wastes product and material. Using one that’s too small leads to cramped application and messy folds. Most busy salons stock at least two sizes - a 15cm×35cm for standard work (300 sheets per box) and a 20cm ×40cm for balayage and long hair (200 sheets per box). Add a 15cm×30cm (500 sheets per box) if you do a lot of face-framing and partials.

How many foils do I need for a full head of highlights/balayage?

A typical full-head highlight or balayage service uses between 40 and 80 foils depending on the client’s hair density, the technique, and how many sections you’re working with. With a 300-sheet box, you’ll get roughly four to seven full-head services per box.

Let’s break it down with a real example. Our Bohemian foil (15×35cm, 300 sheets) is $27.99 per box. If you get 4 full-head services out of a box, that’s $7.00 per client in foil cost. If you’re efficient and get 7 services out of a box, that drops to just $4.00 per client. Either way, your foil cost per service is incredibly low - especially when you consider you’re using premium embossed, pre-cut foil with a design your clients will love.

Are embossed foils better than smooth foils?

Embossed foils grip the hair and hold product in place during processing, which reduces slipping and bleeding between sections. Smooth foils are cheaper upfront but offer less control - and they often end up costing you more when you factor in the real cost of foil rolls.

Is a pre-cut foil box really cheaper than a foil roll?

Let’s do the maths. A standard foil roll costs around $8 and gives you roughly 30 metres of smooth, uncut foil. To replicate our 15×30cm foil, you need to cut the roll into 15cm increments - that’s what gives you the 15cm width. So: 30 metres is 3,000cm, divided by 15cm per cut, which gives you 200 sheets per roll.

To match the 500 pre-cut sheets in our silver 15cm ×30cm box, you’d need to buy 3 rolls (200 + 200 + 100 from the third roll) — that’s $24 in rolls. Our silver 15cm ×30cm box with 500 embossed, pre-cut, pop-up sheets? $22.99. So the rolls are already more expensive before you even factor in the labour.

And that’s where it really falls apart. Someone on your team has to measure and cut 500 individual sheets at 15cm increments, then pre-fold each one. Let’s be generous and say that takes about an hour. If that staff member is earning $30 an hour, you’re now at $24 in rolls plus $30 in labour - that’s $54 to end up with smooth foil that slips during application.

With Alex Loves Colour, you open the box and pull out a sheet - pre-cut to size, embossed for grip, and dispensed like a tissue box. No measuring, no cutting, no wasted staff time. $22.99 for 500 embossed sheets vs $54 for 3 rolls plus an hour of labour - and you still end up with smooth foil. The pre-cut box wins every time.

The Bottom Line

Choosing the right hair foil size isn’t complicated once you know what each size is designed for. Start with a 15cm ×35cm as your daily driver - it’s our fastest seller for a reason, with 300 sheets per box and enough length for most clients. Add a 20cm ×40cm for balayage and extra-long hair, and keep a box of 15cm ×30cm on hand for face-framing and partials. Match the foil to the technique and the hair length, and you’ll work faster, waste less and get cleaner results.

At Alex Loves Colour, we make professional hair foils with embossed texture, pre-cut pop-up design and 100% recyclable materials - in every size you need. Browse our full range at alexlovescolour.com.au and find the size that’s right for your colour bar.

Quick Reference: Which Size Do I Need?

Here’s a quick cheat sheet to keep behind your colour bar.