envelope size guide

Q&A: What Are The Different Envelope Sizes?

An explanation of standard envelope sizes from C4 to C7

If you are confused by the terminology, and don’t quite get the difference between A5 and C5, then this simple envelope size guide will hopefully explain everything.

What do the A and the C mean?

Envelopes and paper have their own measurement system and at first it can seem a little baffling. It is actually quite simple, although I’ll admit it doesn’t help itself to make it easy!

Remember – A stands for paper and C stands for envelopes. Easy, right?

Starting with paper, A0 is actually 1 sqm. Yes, very metric. A1 is a sheet of A0 folded in half. A2 is half of A1 and so on down the line.

Envelopes sizes are listed under the prefix of ‘C’. Why remains a mystery but it really doesn’t matter. All you need to know is that envelopes are defined by a ‘C’ size and this corresponds to an equivalent ‘A’ paper size. The C size is a bit larger to accommodate the insert.

So that means that a flat sheet of A4 paper will require a C4 envelope if you don’t want to fold it. An A5 sheet will require a C5 envelope, and so on down.

universal paper sizes
Universal Paper Sizes from A0 to A7
‘C’ envelope sizesdimensionsequivalent to…’A’ paper sizesdimensions
C0917 x 1297 mmA0841 x 1189 mm
C1648 x 917 mmA1594 x 841 mm
C2548 x 648 mmA2420 x 594 mm
C3324 x 548 mmA3297 x 420 mm
C4229 x 324 mmA4210 x 297 mm
C5162 x 229 mmA5148 x 210 mm
C6114 x 162 mmA6105 x 148 mm
C781 x 114 mmA774 x 105 mm
C857 x 81 mmA852 x 74 mm
C940 x 57 mmA937 x 52 mm
C1028 x 40 mmA1026 x 37 mm
tips for choosing the right envelope

Tips: 5 Top Tips To Choose The Right Envelope

our tips for choosing the right envelope

Based on many years of experience, watching people make the same mistake and order the wrong envelope, we have put together this simple yet handy guide to help you choose the right envelope.

1. Choose your envelope size first

If we had a penny every person who had designed their card before finding the envelope…

It’s a basic fact that envelopes come in a lot of sizes, but it’s also the case that it’s diminishing returns the more unusual the size. So when you choose your envelope size, go for a standard envelope size and you will find an incredible choice of colours, finishes and designs. Go for something a bit unusual and you may end up with just white. If you’re lucky.

2. Check the exact size

You need to take account of two sizes. One is the envelope size (which we quote on all products). The second is the size of what you are putting into it.

To get your insert into the envelope you will need a bit of room. Not much, but enough to fit it in. We suggest a 5mm difference. Even 10mm is fine. It might sound a lot but 10mm will give you just a 5mm gap on either side, and if you measure it out, it’s not much. But that small gap will let you slip something into the envelope rather than spending 10 minutes forcing the card into the envelope only to see the envelope tear anyway.

There is a slight complication to this rule. It assumes that you are just putting a ‘normal’ card into the envelope. In the unusual scenario where you have something a bit bulkier, then you need to allow a bit more. Ultimately there is no rule here so you will only know by getting a sample and trying it yourself. Click here to visit our sample request page.

3. Get the right flap

This one comes down to personal choice. And availability! The choices are diamond or wallet.

Diamond – this is where the flap is pointed and meets in the middle. It is the classic envelope style and so has a more traditional feel.

Wallet – this is a straight flap, a simpler and more ‘contemporary’ design.

diamond flap envelope
Diamond flap envelope
wallet flap envelope
Wallet flap envelope

The problem is that some envelopes come with diamond flaps and some with wallet flaps. You might not have a choice – try and factor that into your decision process.

4. Choose your paper

Not all paper is alike! It naturally follows that a heavier paper feels, and is, nicer. Thinner papers will feel…well, a bit cheaper. As a rule of thumb, paper will vary from 80gsm to 120gsm. 80gsm will be ok, but a bit thin. 120gsm will feel like good quality paper. In between, 100gsm is a good quality paper that will be good for all occasions.

What you need to take into account also is the finish – the two you will most likely encounter are wove and laid. Wove is a smooth finish. Laid paper has a slight grain or texture to it. Wove paper has that slight ‘contemporary’ feel whilst laid paper has a more ‘traditional’ feel.

You might also take lined envelopes into consideration. Without going into too much detail, these are envelopes with an inner tissue paper lining which gives a little extra security and a little extra quality feel. Ideal for special invites.

lined envelopes
Lined envelopes

5. Don't leave it until the last minute!

We offer a huge range of envelopes – over a 1,000 at the last count in fact. With that much choice we will only carried a limited range in stock and the rest are special order. That means we will import them specially or you, sometimes from a factory in Switzerland even. But that means there will be a longer lead time on those items, usually about a week extra.

So please check the lead times and allow enough time for delivery to avoid disappointment!

Incowrimo 2017 Letter

Incowrimo 2017 – Writing Letters – Part 2

Incowrimo 2017 Letter

International Correspondence Writing Month. One a day. Every day. February. That's the tag line that got me interested last year 🙂 Are you ready to take on the challenge and put pen to paper?

You can read the first part of our series on Incowrimo 2017 here.

What to write always seems to be the hardest thing about Incowrimo. The good news is that it’s actually easier than you think. Reconnect with people – find something you have in common. Write about something nice 🙂 Be kind, ask questions, or just one 🙂 Keep it light.

I always mention pen and ink combo and then decorate remaining space with doodles, ink splats, stamps, washi tape, stickers, etc.

Plan your incowrimo – it’s perfectly fine to start with few quick thank you notes, postcards, Valentine’s card and slowly build up to letters.

Incrowrimo 2017 postcard ideas

In this second part of our letter writing series, we will be looking at paper and filling those envelopes.

My recommendation for a more sophisticated writing experience are the Original Crown Mill sets. Each box comes with enough stationery to get you through a month of incowrimo, easy.  The laid paper in these sets are the reason why this feels luxurious. Ordinary copier paper is no match for the ribbed texture here which looks and feels more personal. That is the tone we want for Incowrimo 🙂

The Crown Mill comes in two different sets. The gold box comes with cream coloured materials. Silver box contains white paper and envelopes.

Incowrimo 2017 letter on a desk

When I talk about writing letters I have to mention Triomphe. It is a brand of pads and envelopes by Clairefontaine – famous for its glassy smooth 90gsm bright white paper. These pads have plain paper in them and come with a ruled cheat sheet which will magically help you write in neat, straight lines. Simply genius 🙂 Envelopes are lined with white paper and the seal is diamond shaped which makes them perfect contestants for wax seals. They certainly do look classy and are fantastic value for money.

We had these pads reviewed by the wonderful Azizah on her blog. Have a look – there are some fantastic photos which will inspire you 🙂 Perfect incowrimo cue.


My go-to is Rhodia R pad. Some may consider it as a budget option because it is just a pad. Don’t be fooled – it is gorgeous 90gsm buttery smooth ivory paper. We sell them in plain or lined paper. I pick lined over plain because when writing, I can anchor the letters to the lines and find it makes my handwriting look neater. Certain fountain pen inks ‘shine’ on ivory paper, others look great on bright white paper. My top 3 inks for ivory paper are KWZ Honey, Diamine Syrah and J Herbin 1670 Caroube de Chypre. Pages tear out easily, one by one, and it does look rather smart 🙂

Incowrimo 2017 letters with clips and washi tape

Last year we were part of Letters Live 2016 which was a spectacular event, defo check out www.letterslive.com for a spark of inspiration and get on incowrimo.org for further information.

Next week we’ll be helping you out with some ideas and creations we’ve been prepping for our own contribution to Incowrimo 2017 🙂 See you soon!

Incowrimo 2017 letters and ink
Bullet Journal with Incowrimo calendar

Incowrimo 2017 – Writing Letters – Part 1

Bullet Journal with Incowrimo calendar

February, the shortest month of the year is almost here... For many stationery geeks this is the time when we sit down and write one letter a day to someone. INternational COrrespondence WRIting MOnth aka Incowrimo here we go...

In the beginning it was a simple idea – write more letters. Vintage social media beats email/text every time. It is without a doubt more romantic and personal.

February was picked because it is the shortest month of the year. So if you commit, you will only need to write 28 (29 during leap year) letters, cards, postcards, notes, post-its, napkins…

Who you write to is up to you, of course. This is a fantastic way to reconnect with old friends and family. Write to loved ones, write to strangers…or write to us if you like 🙂

To start off Incowrimo, I make a list of 28 souls 🙂 Next step is my favourite one – grab all the stationery which I can find around the house/office and start brainstorming 🙂 The usual ingredients are: envelopes, paper, cards, postcards and stamps. Extras like shimmering inks, washi tape, wax seals, stamps are the cherries on top.

Bullet Journal with Incowrimo calendar

In part one of this letter writing series, we will be looking at envelopes.

Envelopes are the first thing that your recipient will see, so I try to make them stand out.

Colour usually does the trick – your bank would not send you statements in pink envelopes 🙂 Silver and gold envelopes catch the eye and say “you are special.” Plain envelopes are okay – Decorate! Why not recycle any old ones too?  Incowrimo is prime time to open that stationery drawer grab the cute stuff which is too good for use in your journals.

Check carefully that you have the correct address and also write a return address – you never know, one letter can be the beginning of beautiful pen-pal friendship 🙂

Make sure you use some kind of waterproof ink – this goes especially for fountain pen users in UK where we get a lot of rain. Iron Galls should do the trick, if you don’t have such inks, hack it with clear tape over the address or use clear wax to make it waterproof 🙂

I participated in Incowrimo 2016 while I was working on improving my handwriting. Those two go hand in hand and it was really rewarding to put all those hours of practice to some good use. Commiting to do something for a month became a lot easier as soon as I put my mobile away. Go offline and take time to unwind. Sit down, surround yourself with stationery, put nice music on and focus on someone and then just write… It is a very happy place, trust me 🙂 What are the chances that you will start a new hobby after writing 28 letters?

One last piece of advice. If you think that 28 letters is a lot and you will struggle, set yourself some kind of reward – a beautiful pen or new ink works for me every time 🙂

If you would like to join and pledge to write one letter/card/note a day please head over to www.incowrimo.org

In Part 2 of Writing Letters for Incowrimo we’ll focus a bit more on what goes in the envelope… (Hint: It’s paper!)



Envelope Week Has Been Rescheduled

16 – 20 September 2013

For all sorts of reasons, but mainly to allow us to run a special promotion without overlapping with our monthly discount code, we have now moved our Envelope Week back to Monday 16 September for 5 days. That’s 5 days of special features and promotions all about envelopes. And it will actually be quite a surprise how tempting envelopes can be. Watch this space.


Bureau Direct Envelope Week

Also known as National Envelope Week

Earlier in the summer I announced that we would celebrate one of the less-glamorous items of stationery – the envelope – with a week-long series of events. That week is nearly upon us and so my last-minute planning is in overdrive once again, remembering all those little things that need to be done. The idea is simple – we sell one of the best ranges of quality envelopes online, and not enough people know about it. We don’t do your bog-standard manila envelopes, although we do a rather nice range of white business envelopes, but mainly we do coloured envelopes and speciality envelopes. Spread across several brands – Opera, Artoz, Pollen and Casa Metallic – we do an amazing range of colours and sizes. We also do some pretty wonderful envelopes in more luxury or unusual finishes.

Bureau’s Envelope Week was simply to celebrate all that is good in our envelopes, and as Kate pointed out earlier today, envelopes are something of an antidote to the digital age – a bit old fashioned, possibly involving a pen and some ink and actual handwriting. The week will feature something different each day – you’ll have to check in next week to find out more.

Bureau Direct Envelope Week – 9 – 13 September


Staff Picks – Opera Envelopes

opera envelopes

Kate’s Choice

It’s about time I wrote a product review as I’ve been working for Bureau Direct for over 2 years, but when I started here I had absolutely no knowledge of stationery at all. In fact, I remember thinking that I would never get my head around the sheer number of products we stock and trying to learn all of the different envelope sizes was enough to make me break out in a cold sweat. However, slowly but surely the information started to seep into my brain and before I knew it, I’d become a stationery geek….

Although some might argue that there are more exciting products I could have reviewed, I decided to write about something that often gets overlooked, which is our fantastic range of Opera envelopes. It’s amazing the difference that using good quality stationery can make, from switching to a nice pen after years of using throwaway biros, to using a lovely notebook instead of a bog standard pad…So why not switch to gorgeous envelopes too?

Now, as is the case with some of our Lamy pens and Rhodia pads, some of these envelopes are kept in stock and some of them are special order and are only available in boxed quantities, so remember to check the website for information and any lead times. If you’ve never ordered envelopes from us before, be sure to check the sizes first using the very useful chart on our Help page.

Personally, the Vibrant range by Opera is my favourite of their collection, I use the C5 size to send out all my correspondence and colour samples. They are available in all of the popular sizes and come in a great selection of punchy colours including the acid bright Canary Yellow, vivid Pacific Blue and candy coloured Cerise Pink. Made of a superb 120gsm paper with a lovely matte finish and peel and seal closure, they are great value for money and are perfect if like me, you want your stationery to stand out. The great thing about the Vibrant envelopes is that we keep them in stock and they are available in packs of 100, so you can order a few different colours to suit every occasion.

If the Opera Vibrant range is too bright for your needs, the Pastel collection is a good alternative featuring some lovely muted, delicate shades such as Sunlight Yellow and Apple Green. For those of you who like deeper colours, the Intensive range is ideal with 3 classic shades of Claret Red, Oxford Blue and Racing Green.

For more traditional requirements, Opera offer 9 different types of standard style Business envelopes. My top picks include the Premium Pure range which is made from 100% recycled paper and is FSC approved, and the Premium Ultimate is a delicious envelope of the best quality with 135 gsm paper and a really smart white finish.

I never thought I’d use the word delicious about an envelope, but that is what working with stationery does to you. And if you have any questions about the Opera range please feel free to ask, that is what I am here for….


Envelope shop

Over 1,000 different envelopes

We have always offered a wide range of envelopes, from the huge colour choice of Artoz 1001 to the great value of the Opera range. It’s also fair to say that envelopes are not exciting as some of the other stationery we sell, such as a new pen from Lamy or a new notebook range. To address the lack of attention we give envelopes, we have decided to embark on a program of reminding everyone the amazing range and depth of choice that we offer. So here’s a summary.

Our envelope shop is divided into 4 main categories, which are:

Coloured envelopes – high quality, great value and because we offer 3 main brands (Opera, Artoz 1001 and Pollen) we can offer an incredible choice of colour shades. For example, Opera has two shades of red envelope (red and claret), Artoz 1001 has four (red, bordeaux, lobster and fire) and Pollen has two (red and bordeaux). That’s eight different shades of red, as each brand interprets red in its own way.

Speciality envelopes – ideal for special occasions where you’re looking for something a little different. It could be translucent paper, pearlescent paper or one of the many unusual ranges from Artoz like Artoline with its subtle grainy finish.

Business envelopes – perfect for business use where you are looking for an envelope with a little more quality than a bog standard office envelope. White envelopes, cream envelopes, window envelopes, recycled envelopes.

Greeting card envelopes – we have many greeting card suppliers, and we will soon be launching a range of white envelopes which are idea for this purpose, in a selection of sizes that will surely cover all needs.