Grams to fl oz converter
One US fluid ounce of water weighs 29.5735295625 grams, so the tool divides your gram reading by that figure and also shows the milliliters. Weigh water on a scale and get the fluid ounces a US recipe or label expects. Free in your browser.
- Free
- Runs in your browser
- No sign-up
- Your data stays on your device
Run — free
Worked example
- Grams
- 29.5735295625
- Result
- 1 fl_oz
- Fl oz
- 1
- Fluid ounces
- 1
- Ml
- 29.5735295625
A grams to fl oz converter turns a mass of water measured in grams into a volume in US fluid ounces using the standard density of water. Kitchen scales, laboratory balances, and bottled-water labels often report grams, while US recipes, nutrition labels, and serving sizes still speak in fluid ounces. This tool divides the gram mass by the exact millilitre equivalent of one US fluid ounce after applying a water density of one gram per millilitre (one thousand kilograms per cubic metre).
Why grams of water convert to US fluid ounces at a fixed density
A gram is a mass; a US fluid ounce is a volume. Those two quantities are not interchangeable without density, and the identity that connects them is volume equals mass divided by density. This landing uses the standard reference density of water, one thousand kilograms per cubic metre, which is exactly one gram per millilitre—the textbook value near four degrees Celsius where liquid water is densest.
Combined with the exact SI definition of the US fluid ounce—one US liquid gallon is two hundred thirty-one cubic inches with the international inch exactly equal to 2.54 centimetres, hence 3.785411784 litres, and that gallon divides into one hundred twenty-eight US fluid ounces—the millilitre equivalent of one US fluid ounce is 29.5735295625 millilitres exactly. At one gram per millilitre, that same figure is also the mass of one US fluid ounce of water, so fluid ounces equal grams divided by 29.5735295625.
That factor is definitional for this standard-density path, not a weather-dependent survey estimate. Searchers who type grams to fl oz almost always mean a kitchen, lab, or bottled-water mass of water on the gram scale, not avoirdupois ounces of dry goods and not an imperial fluid ounce. This landing therefore stays on grams of water to US fluid ounces only.
It does not convert imperial (UK) fluid ounces, which are smaller at 28.4130625 millilitres and would overstate volume for a US cup. It does not convert avoirdupois weight ounces, which are a mass unit of 28.349523125 grams and have nothing to do with fluid volume.
Practical tips, checks, and related searches
Round-trip sanity checks are easy: convert 29.5735295625 grams and confirm you receive one US fluid ounce and 29.5735295625 millilitres after rounding, convert one hundred grams and confirm about 3.381402270184 fluid ounces, or convert zero and confirm zero. When teaching, show that multiplying the published fluid ounces by 29.5735295625 recovers the millilitre volume, and that those millilitres equal the original grams at one gram per millilitre within the same twelve-decimal rounding used for published fields.
Stay inside the non-negative range so a kitchen scale typo cannot produce a negative pour the solver must reject. This landing targets people searching for grams to fl oz, grams to fluid ounces, or a water-density calculator; it is not a general multi-unit volume hub, not an avoirdupois ounces-to-grams path, not an imperial fluid-ounce converter, and not a grams-to-cups cooking tool that picks flour or sugar density.
Prefer this capability when the input is already grams of water and you only need US fluid ounces; if you must convert among many kitchen units in one call, use a broader cooking converter instead. When comparing bottled-water labels across countries, remember that this tool divides mass by the standard freshwater density only and does not convert price per gram into price per fluid ounce.
What you can do with it
Kitchen recipes from a gram scale
Turn a weighed pour of water in grams into US fluid ounces for US cup-and-ounce recipes, hydration ratios, and serving-size notes that still list fluid ounces.
Lab, nutrition, and bottled-water labels
Convert a gram mass of water from a balance or nutrition panel into US fluid ounces for serving sizes, reconstitution volumes, and bilingual product labels.
FAQ
What formula converts grams of water to US fluid ounces?
US fl oz = grams ÷ 29.5735295625. One US fluid ounce is 29.5735295625 ml; at 1 g/ml that mass is 29.5735295625 g, so dividing grams by that factor yields fluid ounces.
What water density does the converter use?
The standard reference density 1 g/ml, which is 1000 kg/m³. That is the textbook freshwater value near 4 °C. Seawater, brine, and hot water need a different density and are outside this landing.
Is this the same as ounces to grams or imperial fluid ounces?
No. Input is grams of water only. Output is US fluid ounces of 29.5735295625 ml, not the avoirdupois weight ounce of 28.349523125 g and not the imperial fluid ounce of 28.4130625 ml.
Is the grams to fl oz converter free?
The browser tool is free and runs locally.
How many fluid ounces is 100 grams of water?
100 grams of water are 3.381402270184 US fluid ounces. At 1 gram per milliliter they also fill 100 milliliters, which you can check by multiplying the ounces by 29.5735295625.
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/grams-to-fl-oz \
-H "Authorization: Bearer $KIT_KEY" \
-H "Content-Type: application/json" \
-d '{"grams":100}'const res = await fetch("https://api.kit.forhosting.com/conv/grams-to-fl-oz", {
method: "POST",
headers: {
"Authorization": `Bearer ${process.env.KIT_KEY}`,
"Content-Type": "application/json"
},
body: JSON.stringify({
"grams": 100
})
});
const { task_id } = await res.json();import os, requests
res = requests.post(
"https://api.kit.forhosting.com/conv/grams-to-fl-oz",
headers={"Authorization": f"Bearer {os.environ['KIT_KEY']}"},
json={
"grams": 100
},
)
task_id = res.json()["task_id"]<?php
$res = file_get_contents("https://api.kit.forhosting.com/conv/grams-to-fl-oz", false, stream_context_create([
"http" => [
"method" => "POST",
"header" => "Authorization: Bearer " . getenv("KIT_KEY") . "\r\nContent-Type: application/json",
"content" => '{"grams":100}',
],
]));
$task = json_decode($res, true);body := bytes.NewBufferString(`{"grams":100}`)
req, _ := http.NewRequest("POST", "https://api.kit.forhosting.com/conv/grams-to-fl-oz", body)
req.Header.Set("Authorization", "Bearer "+os.Getenv("KIT_KEY"))
req.Header.Set("Content-Type", "application/json")
res, _ := http.DefaultClient.Do(req)Example request
{
"grams": 100
}Example response
{
"task_id": "tsk_a1b2c3d4e5f6a1b2c3d4e5f6",
"type": "conv.grams_to_fl_oz",
"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
Enter a non-negative finite gram value; the response returns fluid ounces, the intermediate millilitre volume, the fixed factor, a short formula, and ordered substitution steps you can paste into a notebook. A negative mass fails with a clear invalid_input error instead of inventing a volume.
How to call the API and what comes back
Prefer bare numbers when you control the client; string numbers are accepted only when they match a strict finite numeric pattern without unit symbols, thousand separators, or currency marks attached to the value. Send a JSON body with one required non-negative finite number field named grams. Aliases g, mass, value, weight, and grams_value are accepted so SDK clients and form posts can use the name that fits the product. Absolute values must stay within the published limit of one trillion, and a negative gram value is rejected with invalid_input rather than treated as a signed delta. On success the response echoes rounded grams, sets fl_oz, fluid_ounces, and result to the same rounded US-fluid-ounce magnitude, ml to the intermediate volume in millilitres, unit to the token fl_oz, from_unit to g and to_unit to fl_oz, factor to the reciprocal of 29.5735295625, ml_per_us_fl_oz to 29.5735295625, water_density_g_per_ml to 1, water_density_kg_per_m3 to 1000, formula to the string fl_oz equals grams divided by 29.5735295625 at 1 g/ml, message to a short English summary, and steps to an ordered array of substitution lines that show the US fluid-ounce definition, the water density, and the two-step apply. Failed validation—missing fields, non-finite numbers, bare plus or minus signs, non-numeric strings, negative grams, 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.
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 grams or pass a negative placeholder while debugging their client code. Pin the rounded fl_oz in tests, keep the density visible next to the input, and document that temperature and dissolved solids change real density so a laboratory figure beats this textbook constant when legal custody transfer is on the line.
Integration use cases
Homework and unit-test fixtures
Students and engineers convert classroom gram masses of water to US fluid ounces and pin golden JSON so browser and API arithmetic never drift.
Technical questions
What happens if grams is negative or missing?
The API returns invalid_input naming the problem (for example a negative grams value or a mass that is not a finite number). Failed tasks are not charged.