Switch Actuation Force and Distance, Explained
Actuation force (typically ~45–62g on common switches, in grams-force or the near-identical cN) is the force at the moment a key registers — about 1.2–2.0mm into a ~4mm total press. It is not what most typists feel: bottom-out force runs roughly 10–20g higher and is what you meet on every full keystroke. Lighter (~35–45g) vs heavier (~60–80g) is a preference tradeoff — ease vs accidental presses — and "speed" switches that actuate earlier save at most low-single-digit milliseconds against 150–250ms human reaction times. The ~45–55g band is the mainstream compromise.
The one thing to know: Actuation force is how many grams it takes to register a key, and most common switches sit in a narrow ~45–62g band — Cherry MX Red/Brown ~45g, Blue ~50g, heavier tactiles ~55–67g. 'Light' switches (~35–45g) are easier to press but easier to bottom out and mistype on; heavier switches resist accidental presses but tire some hands faster. There is no universally 'best' weight — it's a preference, and the difference between a 45g and 55g switch is smaller than most marketing implies.
The spec-sheet decoder: what every number means
A switch spec sheet packs four or five numbers into one line. Here is what each one is actually measuring — all figures are typical approximate ranges, and individual switches vary with manufacturing tolerance.
| Spec-sheet term | What it measures | Typical range (approx.) | What it means for you |
|---|---|---|---|
| Actuation force (gf / cN / "operating force") | Spring resistance at the exact point the keypress registers | ~45–62g common; "light" ~35–45g; "heavy" ~60–80g | The headline number — but you only feel exactly this if you stop pressing at the actuation point, which almost nobody does |
| Bottom-out force (end force) | Spring resistance at full travel | Usually ~10–20g above actuation force | What heavy typists actually feel on most keystrokes; often omitted from marketing |
| Actuation distance (pre-travel) | How far the key moves before it registers | ~1.2–2.0mm; "speed" switches ~1.0–1.2mm | Shorter = registers sooner and mistypes easier; longer = more deliberate |
| Total travel | Full distance from rest to bottom | ~3.2–4.0mm (standard MX ~4mm) | Shapes how "deep" the press feels; low-profile switches cut this down |
| Tactile force / bump (tactile switches only) | Peak force of the mid-press bump | Often ~5–15g above the listed actuation force | Bump position and steepness dominate feel more than the rated weight does |
gf, cN, "g" — are the units the same?
Effectively yes. Manufacturers mix grams-force (gf), plain "g", and centinewtons (cN) on spec sheets, and for switch purposes they are interchangeable: 1 gf ≈ 0.98 cN, a difference of about 2% — smaller than the unit-to-unit variance between two switches off the same production line. A "45 cN" switch and a "45 gf" switch are the same weight class. Don't let a unit change between two spec sheets make you think you're comparing different weights.
Actuation force vs bottom-out force: which one do you actually feel?
Actuation force is measured at the actuation point — the moment, roughly 1.2–2.0mm down, when the switch registers. But a keystroke doesn't stop there. Most typists press through to the bottom of the ~4mm travel on most keystrokes ("bottoming out"), and by then the spring has compressed further, so the resistance is typically 10–20g higher than the advertised number. A "45g" switch commonly bottoms out around 55–65g. That makes bottom-out force the more honest predictor of what a heavy typist feels all day — and it's usually the number the spec sheet buries or omits. If you're comparing two switches by feel, compare bottom-out figures when you can find them, not just the headline actuation force.
Actuation distance and "speed" switches: does registering sooner matter?
Standard switches actuate around 1.2–2.0mm into a ~3.2–4.0mm total travel. "Speed" or "silver" switches shorten actuation to roughly 1.0–1.2mm, so the key registers a fraction of a millimeter sooner. The math is the honest part: at normal finger-press speeds, that shorter distance saves well under a millisecond — low-single-digit milliseconds at the absolute most — per keypress. Human reaction time, the gap between seeing something and your finger moving at all, runs about 150–250ms. The saving is on the order of a few tenths of one percent of a single reaction. It does not change typing speed (limited by finger coordination, not travel), and it comes with a cost: a shorter, earlier actuation point registers more accidental presses from fingers resting lightly on the keys. Registering sooner is a real spec; mattering is the marketing.
Force curves: why two 50g switches feel completely different
A single force number is one point sampled from a full force curve — a graph of resistance versus key travel — and the shape of that curve is most of what your finger perceives. Two switches both rated 50g can sit on very different curves:
- Linear switches ramp force smoothly from start to bottom. The rated actuation force is just the point where the straight ramp crosses the actuation distance; the press feels even and uninterrupted.
- Tactile switches add a bump — a local peak in the curve. Where that bump sits (early vs mid-press) and how steep it is dominate the feel: a sharp bump right at the top feels much "heavier" than a gentle mid-travel bump, even at an identical rated actuation force.
- Spring type reshapes the curve underneath everything. A standard spring ramps evenly; a progressive spring starts light and stiffens noticeably toward the bottom (discouraging bottom-out); a slow (long) spring is pre-compressed so the force stays more uniform across the whole travel, making the press feel consistent top to bottom.
This is why "what weight should I get?" is only half a question — a 50g sharp-bump tactile on a progressive spring and a 50g linear on a slow spring share a spec-sheet number and almost nothing else.
Lighter, heavier, or middle: which weight should you pick?
There is no best weight — only tradeoffs, and they're preference, not performance:
- Lighter (~35–45g): easier to press, and some typists find lighter springs less tiring across long typing sessions. The tradeoff is typos: light springs actuate from fingers resting on the home row, so accidental presses go up.
- Heavier (~60–80g): a deliberate, planted feel that resists accidental presses — but some hands find the extra resistance more tiring over hours of typing. Popular with typists who like knowing every press was intentional.
- Middle (~45–55g): the mainstream compromise, and where most stock switches ship (Cherry MX Red/Brown ~45g, Blue ~50g). If you can't test switches before buying, this band is the sensible default — the felt difference between 45g and 55g is smaller than most marketing implies.
All of this is comfort-and-preference territory: how a weight feels over a session is personal, and no spring weight is a health or injury claim in either direction. A hot-swap board is the practical answer to uncertainty — try a weight, and change your mind later without soldering (how hot-swap works →).
Related decoders
For the full normalized dataset — every common switch's force, travel, and manufacturer-rated lifespan in one table — see The Switch Numbers Table.
Frequently Asked Questions
Actuation force is the force required at the exact moment the switch registers a keypress — the actuation point — usually listed in grams-force (gf) or centinewtons (cN), which are effectively the same number (1 gf ≈ 0.98 cN). It is NOT the force you feel through a whole keystroke: most typists press past actuation to the bottom, where the spring resists 10–20g more than the listed actuation figure.
Actuation force (~45–62g on most common switches) is measured at the point the key registers, roughly 1.2–2.0mm into the press. Bottom-out force is the spring's resistance at full ~4mm travel, and it typically runs about 10–20g higher — a '45g' switch commonly bottoms out around 55–65g. Since most typists bottom out on most keystrokes, bottom-out force is closer to what a heavy typist actually feels all day, yet spec sheets headline the lighter actuation number.
Not meaningfully. Speed switches shorten actuation distance from the common ~2.0mm to roughly 1.0–1.2mm. At normal finger speeds that saves well under a millisecond, sometimes a low-single-digit millisecond figure at most, against human reaction times of about 150–250ms — a fraction of one percent. Typing speed is limited by finger coordination, not switch travel, so words-per-minute doesn't change. The shorter distance can also raise accidental actuations from lightly resting fingers.
Because a single force number is one point on a full force curve. A linear switch ramps force smoothly from start to bottom; a tactile switch has a bump whose position and steepness dominate the feel — a sharp early bump feels much heavier than a gentle late one at the same rated actuation force. Spring type matters too: a standard spring ramps evenly, a progressive spring stiffens faster near the bottom, and a slow/long spring feels more uniform through the whole press. Same headline number, very different fingers-on experience.
Neither is universally better — it's preference. Some typists find lighter springs (~35–45g) less tiring over long sessions, but light switches actuate from lightly resting fingers, which tends to raise typo rate. Heavier springs (~60–80g) give a deliberate, harder-to-mistype press that some hands find more tiring over hours. The ~45–55g middle band is the mainstream compromise most boards ship, and it's a sensible default if you can't test switches first.
For practical purposes, yes. Grams-force (gf) and centinewtons (cN) measure the same spring resistance in slightly different units: 1 gf ≈ 0.98 cN, a difference of about 2%, far smaller than manufacturing tolerance between individual switches. A switch listed as '45 cN' and one listed as '45 gf' are the same weight class. Some sheets also write just 'g' — read it as gf.
How we work
We're a research-based site: we analyze manufacturer specifications, switch and keycap engineering, and aggregated owner-feedback themes rather than lab-testing every board. We explain tradeoffs plainly, always name a downside, and report measurable specs — never a promise about comfort, strain, or health. Read our full methodology →