Shopping Cart
Your cart is empty.
Search Products
Shopping Cart
Your cart is empty.
Search Products
Finding the right A3 picture frame size is more than just matching numbers. It is about ensuring your artwork, photo, or poster is displayed beautifully while staying well-protected. Many people get confused between the actual A3 paper dimensions and the size of the photo frame needed. Especially when using a mount. That’s where this guide comes in.
In this article, we’ll explain the exact A3 dimensions in millimeters (mm), centimeters (cm), and inches, and show you how to choose the correct frame, both with and without a picture mount. We’ll also provide practical examples and tables to make the process clear and simple. So that you never end up with a picture frame that’s too tight or too loose.
As a brand in the picture framing industry, we’ve been helping customers find the perfect frame for over 28 years. Whether you’re framing certificates, posters, professional artwork, or any other item, this guide provides detailed information about A3 photo frames. Moreover, it will also help you select the best option for your space.
One of the most common mistakes people make is assuming that the dimensions of an A3 print are the same as the dimensions of an A3 photo frame. In reality, the frame you need depends on whether you’re displaying the print directly or adding a mount around it. Getting this right makes the difference between a polished, professional look and a display that feels awkward or unprotected.
A correctly sized picture frame doesn’t just improve appearance; it also enhances it. It plays a vital role in protecting your artwork. A frame that’s too loose can allow the print to shift and become damaged. At the same time, one that’s too tight can cause scratches over time.
The right frame ensures your piece stays flat, secure, and ready to enjoy for years.
Before choosing a picture frame, it is very important to understand the true size of an A3 print. A3 is a part of the ISO 216 international paper standard. It ensures consistent sizing across documents, photos, and artwork.
The exact dimensions of the A3 size are:
| Size Standard | Millimetres (mm) | Centimetres (cm) | Inches (in) |
| A3 | 297 × 420 mm | 29.7 × 42.0 cm | 11.7 × 16.5 in |
These numbers represent the size of the paper or artwork itself. The photo frame you choose may be the same size (if framing without a mount) or larger (if you're adding a mount or decorative border).
Being aware of this difference is crucial in preventing a frequent error. If you purchase a photo frame marked "A3" without verifying whether it is intended for direct artwork placement or if it allows for additional space for a mounting board, you may encounter problems.
When it comes to displaying A3 artwork, certificates, or posters, the choice of picture frame style makes a big difference. The two most common approaches are framing your A3 print directly or using a mount (sometimes called a mat or border) to enhance the display.
If you want a direct fit, an A3 picture frame measures exactly 29.7 × 42 cm (11.7 × 16.5 in). This option is ideal for a clean and modern presentation. It is often used for certificates, posters, and photographs where you want the image to fill the full space.
Browse our full range of A3 Picture Frames available at Alison Kingsgate.
A picture mount is a decorative border placed between the print and the picture frame glazing. It not only adds a professional, gallery-style appearance but also protects your artwork by preventing direct contact with the acrylic or glass.
Benefits of using a mount:
Popular Picture Frame & Mount Combinations for A3 Prints:
| Print Size (A3) | Common Frame Size with Mount |
| 29.7 × 42 cm (11.7 × 16.5 in) | 40 × 50 cm |
| 29.7 × 42 cm (11.7 × 16.5 in) | 16 × 20 in |
At Alison Kingsgate, you can also choose from a wide range of picture mount colours to match your artwork or décor. It will make your A3 display even more personal.
A3 is one of the most popular print sizes. It belongs to the ISO A-series paper standard, which ranges from the large A0 down to smaller formats like A5. The system is simple: each size is exactly half of the one above it when folded along its longest side.
For example, A2 is half the size of A1, and A4 is half the size of A3. This thing makes it easy to scale artwork, posters, or documents while keeping the proportions consistent.
| Size | Cm | MM | Inches |
| A0 | 84.1 × 118.9 | 841 × 1189 | 33.1 × 46.8 |
| A1 | 59.4 × 84.1 | 594 × 841 | 23.4 ×33.1 |
| A2 | 42 × 59.4 | 420 × 594 | 16.5 × 23.4 |
| A3 | 29.7 × 42 | 297 × 420 | 11.7 × 16.5 |
| A4 | 21 × 29.7 | 210 × 297 | 8.3 × 11.7 |
| A5 | 14.8 × 21 | 148 × 210 | 5.8 × 8.3 |
| A6 | 10.5 × 14.8 | 105 × 148 | 4.1 × 5.8 |
At Alison Kingsgate, we stock and manufacture frames across the full A-series range. You can explore our collections here:
Whether you need a statement piece for a large poster or a neat frame for a small certificate, you’ll find a perfect fit within these standard sizes.
When it comes to displaying A3 prints, the right framing choices will not only protect your piece but also bring out its full visual impact. Here are some expert tips to help you make the most of your A3 artwork.
Instead of standard glass, consider UV-protective acrylic. It is lighter, safer, and helps prevent fading caused by sunlight. This thing makes it a better choice for long-term preservation, especially for valuable prints or photographs.
A picture mount creates breathing space between the print and the glazing. It reduces the risk of sticking or moisture damage. Moreover, it also adds a professional gallery-style presentation. For A3 prints, a photo mount is often the difference between a good frame and a great one.
Your picture frame should complement both the artwork and the room in which it is being displayed.
At Alison Kingsgate, we have more than 25 colour options available for picture frames. Moreover, we also have different styles like Modern Picture Frames, Modern Sleek Picture Frames, Imperial Picture Frames, Classic Picture Frames, and more.
Not all A3 artworks are standard prints. Posters, fine art papers, or photographs might need custom framing. A made-to-measure or bespoke picture frame ensures a perfect fit and allows you to choose from a wider range of styles and finishes.
Here is the list of common mistakes to avoid when you decide to frame your art piece in any picture frame.
If you avoid these mistakes, you can frame your artwork in a better way. For further clarity on picture frame sizes, please explore our picture frame size guide.
Q1: What size frame do I need for A3 without a mount?
Ans: An A3 print without a mount requires a picture frame that measures 29.7 × 42 cm (11.7 × 16.5 in). This gives a precise fit with no extra border.
Q2: What size frame do I need for A3 with a mount?
Ans: If you want to use a mount, you’ll need a larger frame. Popular choices include 40 × 50 cm (metric) or 16 × 20 in (imperial). The mount opening is cut to A3 size, so your artwork sits perfectly within the border.
Q3: Can I put an A3 print in a 16×20 frame?
Ans: Yes. A 16×20 in frame with a mount is a common option for A3 prints. The mount acts as a spacer, ensuring your A3 artwork sits neatly inside the larger frame.
Q4: What’s the difference between frame size and paper size?
Ans: The term A3 size refers to the paper or artwork dimensions (29.7 × 42 cm). The frame size is the outer measurement of the frame. If using a mount, the frame must be bigger than the artwork to accommodate both.
Q5: Do Alison Kingsgate frames include mounts and glazing?
Ans: Yes. Many of our A3 frames are available with or without mounts. You can also choose glazing options such as standard or UV-protective acrylic. For tailored choices, we also provide made-to-measure picture frames.
Choosing the right A3 picture frame isn’t just about size. It is about protecting your artwork, enhancing its presentation, and making sure it lasts for years. Whether you prefer a precise A3 photo frame without a picture mount or a larger frame with a picture mount. Alison Kingsgate offers solutions to suit every need regarding framing.
With over 28 years of expertise in picture framing, we understand how to handle delicate prints, posters, certificates, and photographs. All our picture frames are carefully crafted, shipped securely, and designed to complement both modern and traditional interiors. Moreover, we also offer Shirt Frames. If you want to frame any of the shirts, you can buy them from our store.
If you’re working with a different A-series print size, explore our full collection:
For unique artworks, posters, or photos, you can also order a Made-to-Measure Picture Frame. It gives you complete flexibility in size, colour, and finish.