What is the full range covered?

Yotta (10^24) down to yocto (10^-24) — 21 prefixes. Newer prefixes ronna/quecto and ronto/quetto (10^27 and 10^-30) added by the BIPM in 2022 are included where present.

Are kibi/mebi/gibi (binary prefixes) shown?

No — those are IEC binary prefixes (1024-based). SI prefixes are strictly powers of 10. Use binary prefixes when you mean 1024-multiples and SI when you mean 1000-multiples.

How does the converter work?

Type a number with one prefix and see it expressed in every other. Internally values are kept as a single decimal magnitude to avoid float drift across 48 orders of magnitude.

Does it work offline?

Yes. The full table ships with the page.

si prefixes · yotta to yocto · live converter · local

SI prefix reference

Yotta (10²⁴) to yocto (10⁻²⁴) with a live unit converter. Type any number in any prefix and see it expressed in every other prefix.

SI Prefix Reference

Value

(base)

Base

1.00e+0

in base

Prefixes

yotta-yocto

Status

ready

local

input · live converter

prefix table

Name	Power	Factor
yotta	10^24	1000000000000000000000000
zetta	10^21	1000000000000000000000
exa	10^18	1000000000000000000
peta	10^15	1000000000000000
tera	10^12	1000000000000
giga	10^9	1000000000
mega	10^6	1000000
kilo	10^3	1000
hecto	10^2	100
deca	10^1	10
(base)	10^0	1
deci	10^-1	0.1
centi	10^-2	0.01
milli	10^-3	0.001
micro	10^-6	0.000001
nano	10^-9	0.000000001
pico	10^-12	0.000000000001
femto	10^-15	0.000000000000001
atto	10^-18	0.000000000000000001
zepto	10^-21	0.000000000000000000001
yocto	10^-24	0.000000000000000000000001

Quick Start

How SI prefixes work

SI prefixes scale a base unit by powers of 10. Each step in the major series is ×1000 (kilo, mega, giga…); the smaller deci, centi, hecto, deca fill in the middle.

01
Type a number
Any quantity in any prefix.
Inputs are treated as UTF-8 throughout the pipeline and validated client-side as you type — nothing dispatches until the value is well-formed.
valueinpututf-8client-sidevalidated
value · text1 · set
```
1 kilo
```
loaded · parsedclient-side
02
Pick from-prefix
What unit is your input in?
Each toggle re-computes through a memoised hook, so flipping options never resets your input and the UI stays snappy on large inputs.
fromoptionslivememoisedtoggles
from · memoisedk · live
```
kilo (10^3)
```
options set · memoisedlive
03
Read all prefixes
Every prefix shows the same quantity rescaled.
Randomness — where used — comes from crypto.getRandomValues, never Math.random. Heavy work sits in useMemo.
readcomputeinstantlocaldeterministic
out · instantall · computed
```
1k = 1M ÷ 1000
```
computed · instantinstant
04
Copy
Click any cell to copy the rescaled value.
Copy writes through navigator.clipboard and downloads use a Blob — zero network traffic. Same input plus same options always yield the same bytes.
copydownloadzero-networkreproducible
ok · copiedready · copied
```
Copied 1000
```
shipped · ready to shipsuccess

Pro tips

Pro tips for everyday utilities

Reach for crypto.getRandomValues

Cryptographically random for IDs, tokens, salts. Math.random is for animation and games, not security.

Sort IDs lexicographically

UUID v4 has no time ordering. Use ULID or UUID v7 if you need sorted IDs.

Mock data with seeds

Faker-style libraries can be seeded so tests are reproducible. Embed the seed in the fixture file.

Reference cards beat memory

Cheatsheets for Vim, Git, Docker, Linux signals are faster than man pages when you’re mid-flow.

Browser APIs vary

Touch events, gamepads, and clipboard differ across vendors. Feature-detect before use.

Persist in the right place

localStorage for user preferences, sessionStorage for transient state, IndexedDB for structured data.

Use Cases

When to convert SI prefixes

Physics, chemistry, engineering, electronics.

Physics homework

Convert nm to µm to mm in one place. Random values come from crypto.getRandomValues — cryptographically secure for tokens, salts, and session IDs. Math.random is deterministic enough for animations but predictable enough to be a security bug.

CSPRNG-backed

Engineering specs

Datasheets often mix Hz, kHz, MHz, GHz. Pair with hashids, ULID, or UUID v7 when you need both random and sortable — useful for primary keys, public-facing IDs, and event log ordering without a sequence column.

reproducible

Network speed

Megabits vs gigabits without typos. Output is deterministic given the same seed, so fixtures and tests stay reproducible across CI runs and contributor machines. Embed the seed in the fixture file for full replay.

snappy

Lab reports

Convert measurements consistently. Heavy work runs through useMemo so the UI stays snappy on large inputs. Same input + same options yields identical bytes — the kind of stability snapshot tests rely on.

feature-detected

Astronomy

Up to yotta when measuring star masses. Storage tools persist to the right backend: localStorage for user preferences, sessionStorage for transient state, IndexedDB for structured data. Pick the right shelf and quota worries disappear.

deterministic

Particle physics

Down to yocto for sub-atomic timescales. Browser feature detection: clipboard, fullscreen, gamepad, and Web Bluetooth APIs gracefully fall back when unavailable. No surprise white screens on Safari or older Firefox.

production-ready

FAQ

Frequently asked questions

What about ronna/quetta?

Added in 2022 (10^27, 10^30). We don't list them yet — open a PR if needed.

Is kilo k or K?

Lowercase k. Uppercase K is reserved for kelvin and binary kilo.

Binary prefixes?

KiB, MiB, GiB use powers of 1024 instead of 1000. Different standard — see IEC 80000-13.

Why deca and hecto?

They exist for completeness; rarely used outside physics. Most engineering jumps in powers of 1000.

Does it run locally?

Yes — bundled in JS. Nothing is sent to a server.

Suggest a tool

Something missing?

Tell us what you need. We ship the top requests every two weeks.

47 in queue·8 shipped this month

Request queued. Thanks!