Voltage converter
5 V is 5000 mV. Convert an electric potential between volts, millivolts, microvolts, kilovolts and megavolts with exact SI prefixes, and get the factor and steps for a lab notebook, a sensor scaling note or a design review. Free in your browser.
- Free
- Runs in your browser
- No sign-up
- Your data stays on your device
Run — free
Worked example
- Value
- 5
- From
- V
- To
- mV
- Result
- 5,000 mV
- Converted
- 5,000
- Value v
- 5
- Factor
- 1,000
A voltage converter turns one electric-potential magnitude into another SI-prefix unit without spreadsheet formulas or mental decade tables. Enter a finite value plus a source unit and a target unit among volts, millivolts, microvolts, kilovolts, and megavolts; the tool returns the converted voltage, the SI intermediate in volts, the exact unit factor applied, and step-by-step substitution lines you can paste into a lab notebook or design review.
Which voltage units are supported and how conversion works
This capability converts among five everyday electric-potential units that dominate circuit design, instrumentation, high-voltage engineering, and laboratory coursework. The volt (V) is the SI coherent unit and the internal hub: every conversion multiplies the input by how many volts equal one source unit, then divides by how many volts equal one target unit. Millivolts use the exact SI milli prefix of one thousandth of a volt.
Microvolts use the exact SI micro prefix of one millionth of a volt and accept both the µV glyph and the ascii uV spelling. Kilovolts use one thousand volts; megavolts use one million volts. Bare uppercase MV is treated as megavolt so it does not collide with lowercase mv millivolt after naive lowercasing.
Same-unit requests succeed and return the input magnitude with a short message that no change of unit was required.
Practical tips, limits, and when to use this landing
Prefer sending bare numbers for value when you control the client; string numbers are accepted only when they match a strict finite numeric pattern without currency symbols or thousand separators. Round-trip checks are straightforward: convert A to B and B back to A and confirm you recover the original within the published twelve-decimal rounding. When teaching SI prefixes, pair classic examples such as five volts to five thousand millivolts, twelve millivolts to twelve thousand microvolts, and two hundred thirty kilovolts to zero point two three megavolts.
Stay inside the absolute range so intermediate volt values cannot overflow.
What you can do with it
Sensor and ADC scaling notes
Firmware and lab notes convert millivolt sensor outputs to volts or microvolts so datasheet tables, ADC full-scale ranges, and UI displays stay consistent.
High-voltage equipment ratings
Power and substation teams convert kilovolt bus and insulator ratings into megavolts or volts for mixed-unit reports and training materials.
Homework and lab potential checks
Students convert V, mV, and µV homework values with deterministic steps they can compare against hand calculations before submission.
FAQ
How do you tell mV from MV?
Lowercase mv and the word millivolt map to millivolts. Uppercase MV and the word megavolt map to megavolts so the SI mega prefix is not lost after lowercasing.
Is the voltage converter free?
The browser tool is free and runs locally.
How many microvolts are in 12 mV?
12 mV is 12000 µV. Each millivolt holds a thousand microvolts, the step you need when a sensor output in millivolts has to match a datasheet table in microvolts.
How do I convert kilovolts to megavolts?
Divide by 1000: 230 kilovolts become 0.23 MV. Power and substation teams use this step to bring bus and insulator ratings into one unit for a mixed report.
Can I type uV instead of µV?
Yes. Both the µ sign and the plain letters uV are read as microvolts, so a value typed on a keyboard without the µ symbol still converts correctly.
Related tools
For developers — API access
Everything on this page is available programmatically. This section is for teams who want to wire it into their own systems; everyone else can just use the tool above.
API endpoint
Prefer to automate it? One authenticated POST creates the task; the result comes back by webhook or a signed link. The same capability also runs here on the web, by email and from Telegram — and soon from our app too.
Call it from your stack
curl -X POST https://api.kit.forhosting.com/conv/voltage \
-H "Authorization: Bearer $KIT_KEY" \
-H "Content-Type: application/json" \
-d '{"value":5,"from":"V","to":"mV"}'const res = await fetch("https://api.kit.forhosting.com/conv/voltage", {
method: "POST",
headers: {
"Authorization": `Bearer ${process.env.KIT_KEY}`,
"Content-Type": "application/json"
},
body: JSON.stringify({
"value": 5,
"from": "V",
"to": "mV"
})
});
const { task_id } = await res.json();import os, requests
res = requests.post(
"https://api.kit.forhosting.com/conv/voltage",
headers={"Authorization": f"Bearer {os.environ['KIT_KEY']}"},
json={
"value": 5,
"from": "V",
"to": "mV"
},
)
task_id = res.json()["task_id"]<?php
$res = file_get_contents("https://api.kit.forhosting.com/conv/voltage", false, stream_context_create([
"http" => [
"method" => "POST",
"header" => "Authorization: Bearer " . getenv("KIT_KEY") . "\r\nContent-Type: application/json",
"content" => '{"value":5,"from":"V","to":"mV"}',
],
]));
$task = json_decode($res, true);body := bytes.NewBufferString(`{"value":5,"from":"V","to":"mV"}`)
req, _ := http.NewRequest("POST", "https://api.kit.forhosting.com/conv/voltage", body)
req.Header.Set("Authorization", "Bearer "+os.Getenv("KIT_KEY"))
req.Header.Set("Content-Type", "application/json")
res, _ := http.DefaultClient.Do(req)Example request
{
"value": 5,
"from": "V",
"to": "mV"
}Example response
{
"task_id": "tsk_a1b2c3d4e5f6a1b2c3d4e5f6",
"type": "conv.voltage",
"status": "queued",
"_links": {
"result": "/tasks/tsk_…/result"
}
}The API is asynchronous: the call returns a task_id immediately and the result arrives by webhook. Polling is capped at 1 req/s per task.
Pricing
Published price — no tokens, no invented credits. A failed task is never charged.
Limits
max_abs | 1000000000000 |
Errors
| HTTP | Code | Meaning |
|---|---|---|
401 | unauthorized | Missing or invalid API key. |
402 | insufficient_balance | Your balance doesn't cover the task price. |
404 | unknown_type | That task type doesn't exist. |
429 | rate_limited | Too many requests. Use the webhook instead of polling. |
Technical notes
Unknown unit names fail with a clear invalid_input error instead of silent wrong factors.
Which voltage units are supported and how conversion works
If the name is not on that list the solver rejects the request with invalid_input naming the bad field and listing supported units, so clients never guess whether a typo produced a wrong number. Negative voltages are allowed for signed potential difference contexts; absolute magnitude must stay within the published one-trillion limit so intermediate products remain finite in IEEE double precision on the Worker and in the browser.
How to call the API and read the response
Value must be a finite number or a strict numeric string within absolute limits of one trillion. Wire this into dashboards, mobile clients, or batch jobs that already hold a voltage reading and only need a second unit for display or regulatory comparison without shipping floating conversion tables in every app binary. Send a JSON body with three required fields: value (aliases voltage, amount, and v), from (aliases from_unit, unit_from, and source), and to (aliases to_unit, unit_to, and target). From and to must resolve to supported unit names after alias normalization. On success the response echoes the rounded input value, canonical from and to labels, result and converted set to the same rounded target magnitude, value_v as the SI intermediate in volts, unit as the target label, factor as from-to multiplier, formula as the short equation string, message as an English summary, steps as ordered substitution lines, and supported_units as the five canonical identifiers. Failed validation—missing fields, non-finite numbers, values outside absolute limits, or an unknown unit name—returns invalid_input and is never charged. Pricing is a flat $0.002 per successful request with unit item and zero marginal unit price.
Practical tips, limits, and when to use this landing
Prefer this capability when both endpoints are among the five supported potential units and you need deterministic factors and step strings; if you need resistance-based drop along a conductor or duty-cycle average voltage, use the dedicated electrical calculators instead. Failed tasks that return invalid_input do not consume prepaid balance, which keeps exploratory scripts cheap when clients deliberately probe unknown unit names.
Technical questions
Which voltage units can I convert?
Volts (V), millivolts (mV), microvolts (µV or uV), kilovolts (kV), and megavolts (MV), including common full-word aliases such as millivolt and kilovolts.
What happens if I send an unknown unit name?
The API returns invalid_input, names the bad field, and lists the supported units. The failed task is not charged.
Are results deterministic across browser and API?
Yes. Handler and widget share the same lib.js solve path with fixed SI prefix factors and twelve-decimal rounding, so golden examples match production.