# Volume Converter

> Volume converter that switches between liters, gallons, cups, milliliters, cubic meters, and more instantly. Free, private, runs in your browser, no signup.

- **Canonical URL:** https://boringtoolskit.com/volume-converter/
- **Category:** Converters
- **Evidence level:** authored-methodology
- **Reviewed:** 2026-09-20
- **Last verified:** 2026-10-12
- **Privacy:** Inputs and results stay in this browser unless the page clearly labels an external request.

## How it works

Volume = value x (litres per source unit) / (litres per target unit). Factors: 1 US gal = 3.785411784 L, 1 US qt = 0.946352946 L, 1 US cup = 0.2365882365 L, 1 US fl oz = 0.02957352956 L, 1 mL = 0.001 L.

## Worked example

1 US gallon = 3.785 liter · 1 US cup = 236.6 milliliter · 1 US tablespoon = 14.79 milliliter

## Assumptions

- Inputs are treated as exact decimal values.
- Standard (not historical or survey) unit definitions are used.
- The calculation uses the factors at the precision shown in the formula panel; rounding beyond that is display-only and adds no accuracy.

## Common questions

### Why convert through liter instead of directly?

Routing every unit through a single base (liter) means each unit needs only one exact factor against the standard, and any pair combines cleanly. Direct pair factors drift apart over time in hand-maintained tables; a base-unit graph cannot.

### Where do these exact factors come from?

From published standards (NIST: SI units and US customary conversion tables). Units like the inch are defined exactly (1 in = 2.54 cm since 1959), so conversions between standard units are exact, not approximate.

### How many decimal places should I trust?

The math is exact to the precision shown. The practical limit is your input: a tape measure is only good to ~1 mm and a kitchen scale to ~1 g, so 3–4 significant figures already exceeds the measurement's own accuracy.

## Sources

- [SI units and US customary conversion tables](https://www.nist.gov/pml/weights-and-measures)

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