Layout Design Philosophy
Keyboard layouts are not random rearrangements of QWERTY. Each modern layout follows a design philosophy that prioritises certain metrics over others. Understanding these philosophies is the fastest way to narrow the field from hundreds of layouts to a handful of real candidates.
This note classifies layouts into five categories, explains what each optimises for and who it suits, and provides a decision guide. The categories come from the keyboard layout community’s analysis of how consonant/vowel placement drives the stats.
Source: Keyboard Layouts Doc (3rd Edition)
Background: the metrics that matter
Before diving into categories, here is what the key metrics measure (each links to the full definition in Keyboard Layout Metrics):
- SFB (Same Finger Bigram) — two consecutive keys pressed by the same finger. Lower is better.
- SFS (Same Finger Skipgram) — same finger, separated by one key. Lower is better.
- Rolls — a trigram (three consecutive keys) where two keys are on one hand and one on the other, with the two same-hand keys pressed in sequence. Higher is better. Rolls can be inward (toward the index finger, e.g. ring-middle-index) or outward (toward the pinky).
- Alternation — a trigram where each key alternates hands (left-right-left or right-left-right). Higher means a more rhythmic, hand-switching style.
- Redirects — a same-hand trigram where the finger direction reverses (e.g. index-ring-middle). Lower is better; redirects feel awkward.
- In:out-roll ratio — inward rolls divided by outward rolls. A ratio above 1.0 means the layout favours inward rolling.
- Scissors — a bigram that stretches uncomfortably between top and bottom rows on adjacent fingers. Lower is better.
No layout can maximise every metric simultaneously. Increasing rolls tends to increase redirects. Maximising alternation lowers total rolls. Each design philosophy represents a different set of trade-offs.
The five categories
1. Colemak-like
Core philosophy: Retain Colemak’s proven column assignments and optimise conservatively around them.
Colemak (created by Shai Coleman in 2006) was designed to maximise home row usage, concentrate effort on the index fingers, minimise pinky movement, and favour rolling. Colemak-like layouts keep the recognisable structure — typically the HNLM or FNHPB index column, the WR ring column, and the ARST or similar home row — while fixing known weaknesses (high SFS, certain SFBs, the H/D center column issue).
Key traits:
- Familiar finger memory if coming from Colemak or Colemak DH.
- Very low pinky movement (often the lowest of any category).
- High redirects — the main weakness inherited from Colemak’s column structure.
- In-roll ratio is very low (~1.0), meaning inward and outward rolls are roughly equal.
Who it is for: Typists who already use Colemak and want incremental improvement, or anyone who values extensive community documentation, proven track record, and low risk over bleeding-edge optimisation.
Example layouts: Colemak DH, ColemaQ, Colemak Qi, Colemak Qi;x, Arts, Isrt, Irst.
Typical stats profile:
| Metric | Level |
|---|---|
| SFB | Mid to Low |
| Rolls | Mid to Mid-high |
| Alternation | Low to Mid-low |
| Redirects | High to Very high |
| In:out-roll | Very low (~1.0) |
| Pinky off | Min to Very low |
2. In-roll
Core philosophy: Maximise the ratio of inward rolls to outward rolls. Fingers should flow from pinky toward index, not the reverse.
The argument for in-rolls is physical: it is easier to smoothly curl fingers inward (pinky to index) than to splay them outward. To achieve high in-roll ratios, these layouts split the letters N and H across different hands — a critical structural choice. H rolls as H-then-vowel (so it belongs on the pinky of the vowel hand, making HE, HA, HI inward). N rolls as vowel-then-N (so it belongs on the index of the vowel hand, making IN, AN, EN inward). Placing N and H on the same finger (the common NH column) makes it impossible to optimise in-rolls for both, so in-roll layouts avoid that column entirely.
Key traits:
- High in:out-roll ratio (2.5 to 4.4, vs ~1.0 for Colemak-like).
- N and H are on separate hands (or at minimum separate fingers).
- Vowel arrangement is constrained to support directional rolling (specific vowel blocks like YI-OE-UA or YI-OA-UE).
- Higher pinky load than other categories because letters get pushed to the corners.
- SFBs tend to be slightly higher on average due to column constraints.
Who it is for: Typists who notice and dislike the “jarring” feeling of outward rolls, and who prioritise the smoothness of consistent inward finger motion over raw rolling volume.
Example layouts: APT, Wreathy, Mir, Hyperroll, Vylet, Saiga.
Typical stats profile:
| Metric | Level |
|---|---|
| SFB | Low to Mid |
| Rolls | Mid-high to Max |
| Alternation | Mid-low to High |
| Redirects | Very low to Mid |
| In:out-roll | High to Max (2.5–4.4) |
| Pinky off | Mid to High |
3. High Roll / Mid Redirect
Core philosophy: Maximise total rolling volume (both inward and outward) while keeping redirects at a moderate level.
These layouts move the letter H plus additional consonants (like N, M, L, F, or B) to the vowel hand’s index finger. This creates many two-key same-hand sequences — rolls — because the index finger hosts frequent consonants that pair heavily with adjacent vowels. The trade-off is that H on the vowel-hand index makes all H-vowel bigrams (HE, HA, HI, HO) into outward rolls, so the in:out-roll ratio drops below 1.0. Redirects are moderate because having all vowels plus H on one hand is the arrangement that best minimises them, but adding more consonants (N, M, L) to the vowel side increases them somewhat.
Key traits:
- Very high total rolls (often 48–52%, among the highest of any category).
- In-roll ratio below 1.0 (outward rolls dominate because of H’s position).
- Moderate redirects — higher than alternation layouts, but lower than Colemak-like.
- The consonant hand has a clean, low-redirect home row.
Common vowel-hand setups: NH + vowels (most popular), FHNB + vowels, FHMB + vowels, HML + vowels.
Who it is for: Typists who want the smoothest, most “flowing” feel with maximum same-hand sequences, and who do not mind that those rolls are a mix of inward and outward. Popular in the ergo/split keyboard community.
Example layouts: Sturdy, Stronk, Pine, Canary, Nerps.
Typical stats profile:
| Metric | Level |
|---|---|
| SFB | Very low to Low |
| Rolls | Very high to Max (48–52%) |
| Alternation | Low |
| Redirects | Mid to Mid-high |
| In:out-roll | Very low to Low (<1.0) |
| Pinky off | Low to Mid |
4. 3-Roll
Core philosophy: Maximise 3-finger rolling chains (trigrams where all three keys are on the same hand, pressed in one smooth directional sweep).
Most layouts produce 2–4% three-finger rolls (called 3rolls). 3-roll layouts push this up to ~10% by splitting the vowels across hands (typically 3 vowels on one side, 2 on the other) so that critical trigrams like THE, ING, AND, HER, ION, and FOR become same-hand directional sweeps. The result is a gliding, extended-roll feel — the typist’s fingers chain together in longer sequences than in any other category.
Key traits:
- Highest combined rolling (2rolls + 3rolls) of any category.
- Lowest alternation — vowels are split, so hand-switching is minimised.
- Unusual vowel placement: vowels appear on both hands rather than being consolidated.
- Requires careful column design to avoid SFBs with the split vowel arrangement.
Who it is for: Typists who want the longest possible flowing sequences and enjoy the “gliding” sensation of 3+ keys chaining smoothly on one hand. Best appreciated at higher typing speeds where the chains become fluid.
Example layouts: Seht Drai, Snorkle, Ints.
Typical stats profile:
| Metric | Level |
|---|---|
| SFB | Low to Mid |
| Rolls | Very high to Max |
| Alternation | Very low to Low |
| Redirects | Mid to High |
| In:out-roll | Varies |
| Pinky off | Mid to High |
5. Alternation
Core philosophy: Maximise hand alternation — every other keypress switches hands, creating a steady rhythmic drumbeat.
To achieve high alternation, all vowels go on one hand and only certain consonants (H, C, D, S, T) join them. These consonants are chosen because their bigrams with vowels tend to produce alternation rather than rolls. The key insight: consonants like N, R, and L roll heavily with vowels (their bigrams are frequently same-hand), so placing them on the vowel side would increase rolling at alternation’s expense. By contrast, H + vowels produces high alternation because H precedes vowels (H→E, H→A, H→I) creating a consonant-hand-then-vowel-hand alternation pattern, while consonants like T and S also alternate well.
Key traits:
- Highest alternation of any category (38–47%).
- Low total rolls (the inherent trade-off).
- Very low redirects — alternation is the strongest redirect-reducer because fewer trigrams stay on one hand.
- Predictable, rhythmic feel; both hands share the workload evenly.
Who it is for: Typists who prefer a steady, predictable rhythm over flowing sequences. If you find long same-hand sequences uncomfortable or disorienting, alternation layouts eliminate them. Also suits typists who value low redirects above all else.
Example layouts: Graphite, Gallium, Maya, Noctum, MTGAP.
Typical stats profile:
| Metric | Level |
|---|---|
| SFB | Very low to Mid |
| Rolls | Mid-low to Mid |
| Alternation | High to Max (38–47%) |
| Redirects | Very low to Low |
| In:out-roll | Low to Mid |
| Pinky off | Low to Mid |
Comparison table
A representative layout from each category, measured with the Genkey analyser on the MonkeyRacer corpus:
| Category | Example | SFB | Rolls | Alt | Redir | In:out | Pinky off |
|---|---|---|---|---|---|---|---|
| Colemak-like | Colemak DH | 1.18 (Mid-high) | 46.0 (Mid-high) | 29.6 (Low) | 12.1 (Very high) | 1.0 (Very low) | 1.2 (Min) |
| In-roll | Hyperroll | 0.97 (Mid) | 45.3 (Mid-high) | 39.3 (High) | 3.0 (Very low) | 4.2 (Max) | 6.0 (High) |
| High Roll | Sturdy | ~0.6 (Very low) | ~50 (Very high) | ~28 (Low) | ~5 (Mid-low) | ~0.8 (Min) | ~4 (Mid) |
| 3-Roll | Seht Drai | ~0.7 (Low) | ~48 (High) | ~25 (Low) | ~6 (Mid) | varies | ~5 (Mid) |
| Alternation | Graphite | ~0.7 (Low) | ~43 (Mid) | ~42 (High) | ~3 (Very low) | ~1.5 (Low) | ~4 (Mid) |
Reading the table
Lower is better for SFB, Redir, and Pinky off. Higher is better for Rolls, Alt, and In:out. No single layout can be green in every column — the categories represent fundamental trade-offs.
Stats thresholds reference
These are the boundaries used to classify layout stats as Low, Mid, High, etc. The thresholds come from surveying the range of values across known layouts.
Metrics you want to maximise (alternation, rolling, in:out-roll):
| Min | Very low | Low | Mid-low | Mid | Mid-high | High | Very high | Max | |
|---|---|---|---|---|---|---|---|---|---|
| Alt | 23.9 | 26.8 | 29.7 | 32.6 | 35.4 | 38.3 | 41.2 | 44.1–47 | |
| Roll | 37.8 | 39.7 | 41.5 | 43.3 | 45.2 | 47.0 | 48.8 | 50.6–52.5 | |
| In:out | 0.8 | 1.2 | 1.7 | 2.1 | 2.6 | 3.0 | 3.5 | 3.9–4.4 |
Metrics you want to minimise (SFB, SFS, scissors, redirects, pinky off):
| Min | Very low | Low | Mid-low | Mid | Mid-high | High | |
|---|---|---|---|---|---|---|---|
| SFB | 0.525 | 0.625 | 0.735 | 0.875 | 1.075 | 1.375 | |
| SFS | 5.3 | 5.7 | 6.1 | 6.5 | 6.9 | 7.3 | |
| Scissors | 0.1 | 0.15 | 0.25 | 0.35 | 0.45 | 0.55 | 0.7 |
| Redir | 2.8 | 3.6 | 4.5 | 5.4 | 6.2 | 7.0–9.0 | |
| Pinky off | 1.8 | 2.7 | 3.5 | 4.3 | 5.2 | 5.9 | 6.8 |
Hand balance is “even” up to 52–48, “leans left/right” up to 55–45, and “heavy left/right” beyond that.
Which philosophy should you choose?
There is no objectively best category — the right choice depends on what you value as a typist. Here is practical guidance:
If you want the safest, most documented choice: Colemak DH (Colemak-like). It has the largest community, the most key remapping guides, and works on every keyboard form factor. The trade-off — high redirects — bothers some people and not others. Start here if you are unsure.
If you want smooth, flowing text with maximum rolling: High Roll / Mid Redirect (e.g. Sturdy, Pine). Your fingers chain together in frequent two-key sequences. The rolls will be a mix of inward and outward. Popular in the ergo/split keyboard community.
If you care about roll direction and want consistent inward flow: In-roll (e.g. APT, Wreathy). Every roll feels like fingers curling naturally inward. The cost is higher pinky load and slightly higher SFBs.
If you want the longest rolling chains (3+ keys): 3-Roll (e.g. Seht Drai, Ints). These layouts split vowels across hands to create extended gliding sequences. Unusual and experimental, but rewarding at high speed.
If you want a typing rhythm like a drumbeat: Alternation (e.g. Graphite, Gallium). Hands alternate constantly, minimising long same-hand sequences. Very low redirects. The trade-off is fewer rolls.
If you are on a columnar split board and want to experiment: Any category works on columnar boards, but In-roll and High Roll layouts are particularly popular in the ergo community because the columnar key layout eliminates row stagger that can interfere with roll comfort. The Voyager’s limited thumb keys also pair well with layouts that use a thumb letter — many In-roll and High Roll layouts have thumb-letter variants.
Do not over-optimise on paper
Stats matter, but the feel of a layout is personal. Two layouts with identical SFB numbers can feel very different because of how the bigrams distribute across fingers. The best approach: pick a category that matches your preference (rhythm vs flow vs safety), choose a well-known layout from that category, and commit to it for at least 2–4 weeks before judging.