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The right ink bottle size can make your fountain pen routine easier, cleaner, and more enjoyable. Whether you are testing new colours, writing every day, or building a thoughtful ink collection, 20ml, 38ml, and 85ml bottles each serve a different purpose.
The main difference between 20ml, 38ml, and 85ml fountain pen ink bottles is how much ink they hold and how they fit your writing habits. A 20ml bottle is ideal for sampling and variety, a 38ml bottle suits regular writers, and an 85ml bottle offers better value for favourite colours you use often.
In this guide, you’ll learn how each bottle size affects cost, storage, filling, travel, collecting, and everyday writing so you can choose the best option with confidence.
Key Takeaways
- Bottle size changes both cost and how you build your ink collection
- 20ml bottles let you try more colours; 85ml bottles save money on favourites
- How often you write and your colour preferences help you decide which size works best
How Bottle Sizes Change the Writing Experience
Bottle size isn’t just about volume. It affects how you fill your pen, how you store your inks, and whether you can toss your favourite bottle in a bag for travel.
Typical 20ml, 38ml, and 85ml Bottle Features
A 20ml ink bottle usually stands about 5-6cm tall with a narrow opening. Most pens fit in these, but if you use a big pen, you might struggle once the ink level drops.
The 38ml bottle is a bit wider and stands around 7-8cm. That extra width helps most pens fit, though some really oversized models still won’t go in easily. The shape varies a lot, since some brands use short, squat bottles while others go taller.
An 85ml bottle is much bigger at 9-11cm tall. These almost always have a wide opening for easier filling, and sometimes you’ll see extras like reservoirs or inkwell sections to trap ink near the top. The glass feels thicker and heavier, so it’s a solid presence on your desk.
Brands usually add features to 85ml bottles to help you use every drop, since you’re making a bigger commitment to that colour.
The Impact of Bottle Size on Desk Space and Portability
20ml bottles fit just about anywhere, including desk drawers, travel bags, and even big pen cases. You can build a colourful collection without taking over your shelves, and they’re light enough to bring to work or class. The downside? You’ll replace them often if you use a colour a lot.
A 38ml bottle needs a spot on your desk or shelf, but it’s still portable if you travel now and then. It’s a good middle ground for people who like variety but still want a decent amount of ink on hand.
The 85ml bottle is a commitment. It takes up serious desk space and, honestly, isn’t something you’ll want to travel with. When full, it’s heavy, and you’ll need to plan where to keep it. But if you’ve found a colour you love and use every day, the space is worth it for the value.
Which Size Is Best for Beginners, Everyday Writers, and Collectors?
Picking the right bottle size really depends on how much you write and whether you’re still exploring or have settled on favourites. Small bottles are for trying things out, medium and large ones are for regular use, and special editions are for collectors who like a bit of flair.
Small Bottles for Sampling and Experimentation
If you’re new to fountain pen inks or just want to try something outside your usual colour zone, start with 20ml bottles. They give you enough ink to see how it shades, flows, and works with different nibs and paper, but you’re not stuck with a huge bottle if you don’t love it.
A 20ml bottle usually lasts three to four weeks if you write regularly. That is plenty of time to decide if a colour makes the cut.
Smaller bottles also make sense financially when you want to build a palette. You can try five or six colours for the price of one or two big bottles, which helps you figure out what really suits your style.
If you like to rotate inks or match colours to your mood or the season, small bottles help you avoid waste. Ink doesn’t spoil fast, but using what you’ve got feels better than letting big bottles gather dust.
Medium and Large Bottles for Regular Users
Once you know your go-to colour, 38ml bottles are a sweet spot between price and practicality. If you fill a pen every week or use ink for work and journaling, this size just works.
An 85ml bottle is for the die-hard fans of a colour. It’ll last six months to a year if you write a lot, depending on your pen and how often you refill.
Bigger bottles bring the price per millilitre way down. If you’ve already finished a 38ml bottle of a colour, moving up to 85ml makes sense and saves money.
Just keep in mind that one big bottle takes up more room than a handful of smaller ones. So, save the 85ml size for those signature colours you know you’ll use up.
Collecting Limited Editions and Special Finishes
Special edition bottles usually show up in 20ml or 38ml sizes, with cool packaging, seasonal themes, or shimmer effects you won’t find in the regular line-up. Collectors love these for the presentation as much as the ink.
Since these releases sell out fast, collectors tend to grab them right away instead of waiting to sample. The small size makes this less risky, since you’re not stuck with 85ml of something you might not like.
Shimmer inks and other specialty finishes are best in 20ml or 38ml bottles. They need more care and aren’t for everyday writing, so it’s nice to have just enough for special projects.
Collectors often display these bottles with their pens. The packaging and bottle shapes turn ink into a bit of desk art and show off your taste.
Understanding Ink Types and Special Effects
Different ink formulas create unique looks on paper, and your bottle size choice often depends on how much you use specialty inks versus everyday ones. Standard dye-based inks work in any bottle size, but shimmer and shading inks need a little more thought.
Standard, Shimmer, and Shading Inks Explained
Standard dye-based fountain pen inks are the go-to for daily writing. They flow smoothly, dry quickly enough, and come in a huge range of colours. You’ll find them in all three bottle sizes since most people use them all the time.
Shimmer inks have tiny metallic particles mixed in. When you write, those particles settle on the page and give your writing a sparkle. They’ll settle at the bottom of the bottle, so give it a gentle shake before filling your pen.
Shading inks show off light and dark areas depending on how much ink pools on the page. If you use a wet nib or absorbent paper, you’ll see more shading. No particles here, so these are easier to clean out of your pen.
Some inks produce sheen, which creates a shiny, colourful surface where the ink pools. You’ll notice this most on smooth, less absorbent paper.
Choosing Bottles by Ink Properties and Colour
Ink properties matter as much as colour when picking a bottle size. If you’re testing a shimmer ink or something wild, 20ml is plenty to play with. For workhorse blacks and blues, go for 38ml or 85ml bottles.
Waterproof and permanent inks need regular use to avoid clogging, so unless you write daily, stick with small bottles. Heavily saturated and effect inks also benefit from smaller sizes and frequent rotation.
Nib size changes how fast you use ink. Broad and stub nibs burn through ink faster than fine points, so you might need a bigger bottle if you use a broad nib every day. We see folks with broad nibs finish a 38ml bottle in two or three months of steady use.
Caring for Shimmer and Special Effect Inks
Shimmer inks need a bit more attention. The metallic particles can settle or clog your pen’s feed. Use shimmer inks in pens with wider feeds and medium or broad nibs. Stub and italic nibs work especially well.
Shake the bottle gently before each fill to mix up the particles. Try to write a few lines every week to keep things moving. If you’re not going to use a pen filled with shimmer ink for a while, flush it with water first.
Always clean your pen after using shimmer inks before switching to something else. The particles can stick around and mess with other inks. Usually, a water flush is enough, but a drop of dish soap can help with stubborn residue.
Shading inks don’t need special maintenance. They behave like regular dye inks, so just stick to your usual pen cleaning routine.
Cost, Value, and Ink Longevity by Bottle Size
Knowing how much value you get from each bottle size helps you decide what to buy, especially if you write a lot or are building a collection.
Price per Millilitre Comparison
Larger bottles almost always give you a better deal per millilitre. A 20ml bottle usually costs $0.40 to $0.65 per ml, depending on the brand. For a 38ml bottle, that drops to about $0.30 to $0.50 per ml.
The best savings show up with 85ml bottles, which often run $0.24 to $0.40 per ml. For example, you might pay $12 for a 20ml bottle ($0.60/ml), but only $20 for an 85ml bottle of the same ink ($0.24/ml). That’s a big difference.
But only buy big bottles if you’ll use them up. Try small bottles first, then upgrade to large sizes for your everyday inks, such as black, blue-black, or whatever you reach for most.
How Long Will Each Bottle Last?
A 20ml bottle gives around 20 refills with a standard converter (about 0.85ml). If you write daily with a medium nib, that’s about 500 pages of A4.
A 38ml bottle stretches to 38 refills and roughly 950 pages. The 85ml bottle can give you 85-100 refills, covering over 2,000 pages with a medium nib.
Fine nibs make your ink last longer; broad nibs use it up faster. How long a bottle lasts really depends on your habits. Someone who journals every day could empty a 20ml bottle in a few weeks, while a casual note-taker might take years.
Practical Considerations: Filling, Using, and Storing
Bottle size isn’t just about how much ink you own, since it changes how you fill your pens, where you stash your collection, and whether you reach for bottles or stick with cartridges.
Ease of Filling Different Pens from 20ml, 38ml, and 85ml Bottles
The 20ml bottle works well for pens with short nibs or converter-style pens that don’t need much ink depth. These small bottles often have wide openings for their size, so you can angle your pen and fill it easily.
With 38ml bottles, you get the most flexible shape for filling. Most pens fit comfortably, and the ink level stays accessible even when you’re halfway through.
The 85ml bottle gets tricky as the ink level drops. When it’s full, filling is easy. Once you’re halfway down, you’ll need to tilt the bottle or decant some ink into a smaller container. Pens with short feeds might not reach the ink unless you dip deeper than you’d like.
It helps to keep a small sample vial handy for transferring ink from big bottles. That way, you get the value of 85ml without the awkward filling angles.
Storage, Travel, and Organizing Your Ink Collection
I usually reach for 20ml bottles when I’m traveling or working at a cramped desk. They slide into pen cases, desk drawers, and even the corners of carry-on bags without hogging space. With a bunch of these small bottles, I can organize by color or by how I use them, and I don’t have to surrender an entire shelf just for ink.
At home, the 38ml size feels like a sweet spot. You can build up a respectable ink collection, but your workspace won’t get overwhelmed. These bottles stack pretty well, and they fit into those drawer organizers meant for makeup or craft supplies.
The big 85ml bottles? I keep those in a dedicated spot at home. They’re just too bulky and heavy to haul around all the time. I’ve set mine up on shallow shelves or inside drawer systems so they don’t tip over easily. Sorting them by color family or brand makes picking the right shade a breeze.
Travel tips:
- Stick with 20ml bottles or decant ink into small sample vials (2-5ml)
- Put a bit of plastic wrap over the opening before screwing the cap on
- Keep bottles upright in a padded case or wrapped in clothes
- Double-check airline liquid restrictions if you’re flying
Cartridges vs. Bottled Inks for Convenient Refilling
When you’re away from home or need a super quick refill at work, ink cartridges are the clear winner. Just pop one in, and you’re back to writing in seconds with no mess and no bottles to juggle.
But if you use fountain pens daily, bottled ink starts making more sense. A 20ml bottle holds about as much ink as 15-20 standard cartridges, but you pay less per milliliter and get way more color options than the handful most brands offer in cartridge form.
A lot of fountain pen fans keep both around. Cartridges are great for travel or meetings when you just want convenience. Bottled ink is perfect for daily writing at home or at your desk, where you can take your time with refills.
Converter systems bridge the gap. These reusable, cartridge-shaped converters let you use bottled ink in pens that normally take cartridges. You’ll need to refill a bit more often than with disposables, but you unlock the whole rainbow of fountain pen ink colors and properties.
Mixing, Customizing, and Displaying Your Collection
Smaller bottles make it easy to experiment with custom ink blends and let you show off a collection that actually reflects your taste. They’re perfect for building themed collections without forcing you to commit to a huge bottle of any single color.
Mixing Ink Colours and Using Samples
I find 20ml bottles are just right for mixing experiments. You’re not stuck with a mountain of ink if a blend doesn’t turn out. Some specialty mixable inks are designed to blend smoothly without clogging your pen. Just remember to only mix inks that are clearly made to work together.
When I’m testing new colors, I like to grab a few 20ml bottles in different base shades and mess around with syringes and dilution liquids. That way, I can try lots of combos without crowding my desk.
I keep a notebook with swatches and the ratios I used for each mix. It’s a lifesaver when I want to recreate a color I loved. I’d start with two-color blends and work up from there. Always test your custom inks on scrap paper before filling up a favorite pen.
Showcasing Bottles as Desk Decor
A row of 20ml or 38ml bottles adds a ton of visual interest to your desk without eating up all your space. The smaller bottles let you display more variety, and some of the labels and glass shapes are honestly pretty cool when you group them together.
Try arranging bottles by color family on a tray or small shelf for a gradient effect. Clear or translucent bottles look especially nice near a window, where the colors can catch the light. You can always rotate seasonal shades to the front if you’re feeling festive.
If desk space is at a premium, vertical storage works wonders. Use small risers or a tiered stand to keep bottles visible and within reach. Some collectors use a dedicated drawer with custom inserts to protect bottles and keep things organized by brand or theme.
Tips for Themed or Story-Driven Collections
Building your collection around a theme gives your ink choices some direction and helps avoid that random “I bought this on a whim” feeling. I’ve seen people focus on nature-inspired shades, vintage hues, or inks that match specific journals or writing projects.
Smaller bottles are perfect for themed collecting. You can try a bunch of variations within a theme without ending up with giant bottles you’ll never finish. For a forest theme, you might pick up several greens, browns, and earth tones in 20ml sizes instead of just one or two big bottles.
You could also organize by season, using pastels for spring, brights for summer, earth tones for fall, and jewel tones for winter. This approach works great if you like rotating inks based on your mood or journal projects. Story-driven collections tied to favorite books, places you’ve visited, or creative projects add a personal touch to your ink shelf.
Frequently Asked Questions
Here are quick answers to common questions about 20ml, 38ml, and 85ml fountain pen ink bottles.
How long does each bottle size typically last for everyday writing versus occasional journaling?
A 20ml bottle may last a few weeks with daily writing and a few months with occasional journaling. A 38ml bottle can last several months for regular use. An 85ml bottle can last six months or longer, especially for lighter writers.
Which bottle size makes the most sense if you like rotating between several ink colours?
Choose 20ml bottles if you rotate colours often. They give you enough ink to enjoy each shade without taking up too much space or leaving you with large unfinished bottles.
Do smaller ink bottles dry out faster once opened, and how can you prevent that?
Smaller bottles do not usually dry out faster if sealed properly. Keep the cap tight, store bottles upright, and place them in a cool, dark area.
Is there any difference in bottle opening size or filling convenience between the smaller and larger options?
Yes. Larger bottles are usually easier to fill from because they have more depth and stability. Smaller bottles may need careful tilting when the ink level gets low.
What is the best bottle size to pack for travel or a small-space desk setup without risking leaks?
A 20ml bottle works best for small desks and light travel. For trips, a 5ml or 10ml sample vial is even safer and easier to pack.
How should you store different bottle sizes to keep ink in good shape over time?
Store all ink bottles upright, tightly closed, and away from heat or direct sunlight. Larger bottles may need a dedicated shelf or drawer so they stay stable and protected.