How Our Calculators Work: Methodology and Data Sources
Every calculator on Literstograms.com runs on the same small set of rules: one formula, one table of density values, and exact unit definitions. This page lays all of them out so you can check any result by hand, understand where it comes from, and know when it is precise enough for your purpose.
Written and maintained by: Shah Nasar
Last updated: October 3, 2026
The Core Formula
Volume and weight are different kinds of measurement, so you cannot convert between them without knowing how dense the liquid is. Density tells you how many grams one milliliter of a liquid weighs. Every volume-to-weight result on this site comes from one formula:
Grams = milliliters × density (g/mL)
Because one liter is 1,000 milliliters, the liters to grams calculator uses the same formula with the volume scaled first: grams = liters × 1,000 × density. Converting the other way, from weight back to volume, divides instead: milliliters = grams ÷ density.
Worked example: 2 liters of olive oil (density 0.91 g/mL) weighs 2 × 1,000 × 0.91 = 1,820 grams. The same 2 liters of honey (density 1.42 g/mL) weighs 2,840 grams. Same volume, very different weight.
Density Values We Use
These are the values built into the calculators’ liquid menus. They are typical figures for each liquid at ordinary room temperature, and the same value is used on every page of the site so results always agree with each other.
| Liquid | Density (g/mL) | Weight of 1 liter |
|---|---|---|
| Water | 1.0 | 1,000 g |
| Milk | 1.03 | 1,030 g |
| Half-and-half | 1.03 | 1,030 g |
| Heavy cream | 1.0 | 1,000 g |
| Vegetable, canola, sunflower, soybean, coconut oil | 0.92 | 920 g |
| Olive oil | 0.91 | 910 g |
| Honey | 1.42 | 1,420 g |
| Molasses | 1.40 | 1,400 g |
| Corn syrup | 1.38 | 1,380 g |
| Maple syrup | 1.32 | 1,320 g |
| Soy sauce | 1.15 | 1,150 g |
| Orange or apple juice | 1.04 | 1,040 g |
| Lemon juice | 1.03 | 1,030 g |
| Vinegar | 1.01 | 1,010 g |
| Coffee (brewed) | 1.0 | 1,000 g |
| Sea water | 1.025 | 1,025 g |
| Glycerin | 1.26 | 1,260 g |
| Motor oil | 0.88 | 880 g |
| Diesel | 0.83 | 830 g |
| Ethanol | 0.789 | 789 g |
| Gasoline | 0.74 | 740 g |
| Mercury | 13.534 | 13,534 g |
If your liquid is not listed, or you have a more exact figure from a product label or data sheet, choose the custom density option. The calculator accepts density in g/mL, kg/L, g/L, kg/m³, mg/mL, mg/L, lb/gal (US), oz/gal (US), and lb/ft³, and converts it to g/mL before running the formula above.
Where the Numbers Come From
Unit definitions follow the exact values set by international agreement and published by the U.S. National Institute of Standards and Technology (NIST). Density values for pure substances such as water, ethanol, glycerin, and mercury match standard physical reference tables. Values for foods and fuels are typical figures from published food-science and industry references; real products vary, so these are representative values rather than measurements of any particular brand.
Why Water Is 1.0 g/mL
Pure water reaches its highest density, 0.99997 g/mL, at about 4 °C. At a typical room temperature of 20 °C it is about 0.998 g/mL. The difference amounts to roughly 2 grams per liter, well under the variation you would get from an ordinary kitchen scale, so the site uses 1.0 g/mL everywhere. That keeps the math clean (1 liter of water = 1,000 grams) and makes every page consistent. If you need lab-grade precision at a known temperature, enter the exact figure using the custom density option.
Unit Definitions
These conversion factors are exact by definition, not estimates:
- 1 liter = 10 deciliters = 100 centiliters = 1,000 milliliters
- 1 gram = 1,000 milligrams = 1,000,000 micrograms = 1,000,000,000 nanograms
- 1 kilogram = 1,000 grams; 1 metric ton = 1,000 kilograms
- 1 pound = 453.59237 grams
- 1 ounce (weight) = 28.349523125 grams
- 1 US fluid ounce = 29.5735295625 milliliters; 1 UK fluid ounce = 28.4130625 milliliters
- 1 US gallon = 3.785411784 liters
Note that an ounce of weight and a fluid ounce of volume are different units. A fluid ounce of water weighs about one weight ounce, but a fluid ounce of honey weighs much more. Our ounce pages always say which one they mean.
Rounding and Display
Calculations run at full precision, and only the displayed result is rounded. Large results show fewer decimal places, small results show more, and very small results (such as nanogram conversions) switch to scientific notation so no meaningful digits are lost. Trailing zeros are dropped, so a result reads 1,820 g rather than 1,820.00 g. Reference tables on each page are rounded to a sensible precision for the amount shown.
How Accurate Are the Results?
The arithmetic itself is exact. The uncertainty lies in the density value. Three things make a real liquid differ from the table:
- Temperature. Most liquids expand when warm. Cooking oils, for example, become roughly 1% lighter per milliliter for every 15 °C or so of warming.
- Composition. Fat content changes milk and cream, sugar content changes juices and syrups, and blend changes fuels.
- Brand and processing. Two bottles of the same product can differ by a percent or two.
For cooking, baking, and everyday estimates, the built-in values are more than accurate enough. For pharmaceutical, laboratory, commercial, or safety-critical work, use a measured density for your exact material, and read our disclaimer on the limits of these tools.
Your Data Stays in Your Browser
Every calculation runs in your own browser the moment you press Convert. The values you enter are not sent to or stored on our servers.
Corrections and Updates
If you find a result that looks wrong, have a better-sourced density value, or would like a liquid added, please get in touch. Confirmed errors are fixed across every affected page, and changes to density values or methods are recorded below.
Change Log
- October 2026: Methodology page published. Water standardized at 1.0 g/mL and maple syrup at 1.32 g/mL across all calculators and tables.