Troy ounces to grams converter
1 troy ounce is exactly 31.1034768 g. Turn the troy-ounce weight of gold, silver or platinum into grams for bullion invoices, assay certificates, jewellery worksheets and shipping manifests, without the rough 31.1 shortcut. Free in your browser.
- Free
- Runs in your browser
- No sign-up
- Your data stays on your device
Run — free
Worked example
- Troy ounces
- 1
- Result
- 31.1034768 g
- Converted
- 31.1034768
- Grams
- 31.1034768
- From unit
- ozt
A troy-ounces-to-grams converter turns a precious-metal mass quoted in troy ounces into the SI gram value used on bullion invoices, assay certificates, jewellery worksheets, and metric lab notebooks. Approximate mental shortcuts such as multiply by thirty-one point one are rejected in favour of the hard-coded constant, so gold and silver records, mint sheets, and homework match metrology tables.
Why troy ounces and grams still meet at 31.1034768
Troy ounces remain the standard mass unit for gold, silver, platinum, and other precious metals on bullion markets, mint product sheets, jewellery appraisals, and coin-collecting inventories that still quote pure metal content in troy ounces rather than avoirdupois ounces or kilograms alone. Grams belong to the SI mass family used on scientific reports, most European and Asian labels, metric laboratory balances, and international shipping manifests that require SI units for customs. The bridge is exact by international metrology, not a survey approximation.
One international troy ounce equals four hundred eighty grains, and since the grain was fixed at exactly zero point zero six four seven nine eight nine one grams, multiplying those factors yields thirty-one point one zero three four seven six eight grams per troy ounce. That makes the conversion a single exact multiplication: grams equals troy ounces times thirty-one point one zero three four seven six eight.
Rough rules of thumb such as multiply by thirty-one point one introduce scale error that shows up on multi-ounce bars or fine-weight assay rows.
Practical tips, checks, and related searches
Prefer sending bare numbers when you control the client; string numbers are accepted only when they match a strict finite numeric pattern without units, thousand separators, or currency symbols. Round-trip sanity checks are easy: convert one troy ounce and confirm you receive exactly thirty-one point one zero three four seven six eight grams after rounding, or convert ten troy ounces and confirm three hundred eleven point zero three four seven six eight grams.
When teaching, pair the exact path with a rough mental shortcut so students see the drift on larger bars, and contrast troy ounces with avoirdupois ounces so nobody confuses kitchen oz with bullion ozt. Stay inside the absolute range so the multiplication cannot overflow into a non-finite result the solver must reject.
This landing targets people searching for troy ounces to grams, convert ozt to g, precious metal gram weight, or an exact thirty-one point one zero three four seven six eight calculator; it is not a general multi-unit mass hub, not a grams-to-troy-ounces primary form, not an avoirdupois or fluid-ounce path, and not a cooking-only kitchen converter. Prefer this capability when the input is already in troy ounces and you only need grams; if you need everyday avoirdupois ounces to grams, use the ounces-to-grams converter instead.
What you can do with it
Bullion invoices and dual-unit sheets
Turn troy-ounce bar and coin masses into grams for international invoices, customs worksheets, and dual-unit product cards with the same exact factor every row.
Jewellery and assay notebooks
Convert troy-ounce scale readings to grams for jewellery worksheets, assay certificates, and fine-weight logs without rough times-31.1 estimates.
FAQ
What formula converts troy ounces to grams?
One international troy ounce is exactly 31.1034768 g (from 480 grains × 0.06479891 g per grain).
Is 31.1034768 exact or approximate?
Exact by international definition. This tool uses the troy ounce from the exact grain mass, not a rough multiply-by-31.1 estimate.
Is a troy ounce the same as an avoirdupois ounce?
No. A troy ounce is about 31.1034768 g; an avoirdupois ounce is 28.349523125 g. Precious metals use troy; kitchen and postal masses usually use avoirdupois.
Is the troy ounces to grams converter free?
The browser tool is free and runs locally.
How many grams is a 10 troy ounce bar?
It is 311.034768 g: 10 multiplied by 31.1034768. The rough 31.1 shortcut gives a slightly lower figure, and that error grows on larger bars and fine-weight assay rows.
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/troy-ounces-to-grams \
-H "Authorization: Bearer $KIT_KEY" \
-H "Content-Type: application/json" \
-d '{"troy_ounces":1}'const res = await fetch("https://api.kit.forhosting.com/conv/troy-ounces-to-grams", {
method: "POST",
headers: {
"Authorization": `Bearer ${process.env.KIT_KEY}`,
"Content-Type": "application/json"
},
body: JSON.stringify({
"troy_ounces": 1
})
});
const { task_id } = await res.json();import os, requests
res = requests.post(
"https://api.kit.forhosting.com/conv/troy-ounces-to-grams",
headers={"Authorization": f"Bearer {os.environ['KIT_KEY']}"},
json={
"troy_ounces": 1
},
)
task_id = res.json()["task_id"]<?php
$res = file_get_contents("https://api.kit.forhosting.com/conv/troy-ounces-to-grams", false, stream_context_create([
"http" => [
"method" => "POST",
"header" => "Authorization: Bearer " . getenv("KIT_KEY") . "\r\nContent-Type: application/json",
"content" => '{"troy_ounces":1}',
],
]));
$task = json_decode($res, true);body := bytes.NewBufferString(`{"troy_ounces":1}`)
req, _ := http.NewRequest("POST", "https://api.kit.forhosting.com/conv/troy-ounces-to-grams", body)
req.Header.Set("Authorization", "Bearer "+os.Getenv("KIT_KEY"))
req.Header.Set("Content-Type", "application/json")
res, _ := http.DefaultClient.Do(req)Example request
{
"troy_ounces": 1
}Example response
{
"task_id": "tsk_a1b2c3d4e5f6a1b2c3d4e5f6",
"type": "conv.troy_ounces_to_grams",
"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.
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
Invalid or missing input fails with a clear invalid_input error instead of inventing a number.
How to call the API and what comes back
Absolute values must stay within the published limit of one trillion. Send a JSON body with one required finite number field named troy_ounces. Aliases troy_oz, ozt, oz_t, troy_ounce, value, mass, and weight are accepted so SDK clients and form posts can use the name that fits the product. On success the response echoes rounded troy_ounces, sets grams, result, and converted to the same rounded gram magnitude, unit to the token g, from_unit to ozt and to_unit to g, factor and g_per_troy_oz to thirty-one point one zero three four seven six eight, formula to the string grams equals troy_ounces times thirty-one point one zero three four seven six eight, message to a short English summary, and steps to an ordered array of substitution lines that show the troy-ounce definition derived from four hundred eighty grains. Failed validation—missing fields, non-finite numbers, bare plus or minus signs, non-numeric strings, values outside absolute limits, or a non-finite converted result—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, checks, and related searches
Failed tasks that return invalid_input do not consume prepaid balance, which keeps exploratory scripts cheap when learners deliberately omit troy_ounces or pass text.
Integration use cases
Homework and unit-test fixtures
Students and engineers convert classroom troy-ounce masses to grams and pin golden JSON so browser and API arithmetic never drift.
Technical questions
What happens on missing or non-numeric input?
The API returns invalid_input naming the problem (for example a missing troy_ounces field). Failed tasks are not charged.