A planner is only as good as the pens you use in it. The right gel pen makes writing in a planner quick, clear and satisfying; the wrong one smears, bleeds through, or puts down a line too thick for the boxes. This guide covers the best choices for every common planner format, from the Hobonichi's 3.7mm grid to standard A5 weekly layouts.
Every pen recommended here is sold at The Journal Shop, so each one links straight to it.
What planners need from pens
Fine tips for small grids. A Hobonichi Techo or a Leuchtturm1917 dot-grid page has a 3.7–5mm grid. At that scale a 0.7mm pen looks clumsy, while a 0.3–0.5mm gel pen keeps notes clean and legible.
Quick drying. Planners are opened and closed all day. Ink that is still wet when the cover shuts prints onto the facing page, so fast drying is a feature, not a luxury.
Colours that stay distinct. If you colour-code, each colour needs to be recognisable at a glance, even at 0.38mm.
Best overall: Zebra Sarasa Clip (0.5mm)
The Zebra Sarasa Clip is the most dependable all-round planner pen we sell. The ink flows smoothly and evenly, the colour range is enormous, and the spring-loaded clip grips a planner cover or pen loop without scratching it. The 0.5mm suits A5 planners and weekly layouts; for smaller formats, see the fine-tip picks below.
Best for tiny grids: Zebra Sarasa Nano (0.3mm)
For Hobonichi daily pages and other small formats, the Sarasa Nano 0.3mm writes a crisp hairline that lets you fit a lot of legible writing into a small space. The muted vintage colours suit a planner particularly well. Very fine gel tips give a little more feedback than broader ones, but on smooth planner paper that is rarely noticeable.
Best for colour-coding: uni-ball One (0.38mm)
The uni-ball One uses an ink designed to keep colour near the surface of the paper, which makes shades noticeably more vivid than an ordinary gel pen. That is exactly what colour-coding needs: different categories you can tell apart at a glance, even in fine lines. The uni-ball One 8-pack is a ready-made coding set, and the One Fika offers the same ink in softer barrels.
Best for fast drying: Zebra Sarasa Dry (0.5mm)
For left-handed writers, or anyone who shuts the planner the instant they finish, the Zebra Sarasa Dry uses a quick-drying formulation designed to stop smearing. Its binder clip slides easily over cover boards and notebook edges.
Best for headers and trackers: uni-ball Signo RT1 (0.5mm)
Month headers, habit trackers and key dates need to stand out. The uni-ball Signo RT1 gives a slightly bolder, well-saturated line that builds a clear visual hierarchy on the page. Its pigment ink is water-resistant once dry, which helps if you highlight over it or carry your planner in the rain.
Best non-gel option: Uni Jetstream Edge (0.28mm)
If gel ink smudges too easily for you, a low-viscosity ballpoint is the answer. The Uni Jetstream Edge 0.28mm writes an extremely fine line with ink that dries almost instantly, which makes it a favourite for dense planner pages and left-handed writers. For several colours in one pen, the Jetstream 4&1 adds a mechanical pencil too.
Practical advice
Test any new pen on a spare page before committing to a full planner setup: what behaves on one paper can show through on another. Thin papers like Tomoe River, used in Hobonichi planners, reward fine tips of 0.3–0.4mm; broader tips put down more ink and show through more. When colour-coding, choose colours with high contrast to each other rather than several similar shades.
For a fuller kit that includes highlighters, fineliners and brush pens, see our guide to the best pens for journaling, or compare gel pens in detail in the best gel pens.
Where to start: browse our planner pens and gel pens.
