Volume Converter Tools – Convert mL, L, cups (US/metric), fl oz (US/UK), pints & gallons
Welcome to the volume conversion hub—your one place to convert between milliliters, liters, cups (US & metric), fluid ounces (US & UK imperial), pints, gallons, tablespoons, and teaspoons. Every calculator uses exact, internationally recognized definitions and a consistent, mobile-first interface.
Whether you’re scaling recipes, formatting nutrition panels, preparing packaging specs, or coordinating cross-border logistics, unit consistency is non-negotiable. Our tools centralize precise constants, compute with full precision, and recommend rounding once at output so your PDFs, emails, and CSV exports stay in agreement.
For team workflows, choose a canonical unit—milliliters for consumer apps or liters for analytics and warehousing—and derive cups, fl oz, pints, and gallons for user interfaces. Each page below includes the exact equation, step-by-step examples, best-practice rounding, and context for regional variants.
US Cups to Milliliters
US customary cup to mL (1 cup = 236.5882365 mL).
Metric Cups to Milliliters
Metric cup to mL (exact: 1 metric cup = 250 mL).
Ounces to Milliliters (US)
US fl oz to mL (exact: 1 fl oz = 29.5735295625 mL).
Milliliters to Ounces (US)
mL to US fluid ounces (exact).
Ounces (UK) to Milliliters
Imperial fl oz to mL (exact: 1 imp fl oz = 28.4130625 mL).
Milliliters to Ounces (UK)
mL to imperial fluid ounces (exact).
Gallons to Liters (US)
US gallon to liters (exact: 1 gal = 3.785411784 L).
Imperial Gallons to Liters
Imp gal to liters (exact: 1 imp gal = 4.54609 L).
US Gallons to Imperial Gallons
Convert US gal ↔ imp gal accurately.
Imperial Gallons to US Gallons
Convert imp gal ↔ US gal precisely.
Liters to Gallons (US)
L to US liquid gallons (exact).
Liters to Imperial Gallons
L to imp gallons (exact).
Liters to Pints
L to pints (US & imperial references).
Pints to Liters
US & imperial pints to liters (exact bases).
Tablespoons to Milliliters
US tbsp = 14.78676478125 mL; metric tbsp = 15 mL.
Teaspoons to Milliliters
US tsp = 4.92892159375 mL; metric tsp = 5 mL.
Milliliters to Tablespoons
mL to tbsp (US & metric references).
Milliliters to Teaspoons
mL to tsp (US & metric references).
Tablespoons to Teaspoons
US standard: 1 tbsp = 3 tsp (exact).
Teaspoons to Tablespoons
US standard: 3 tsp = 1 tbsp (exact).
Why Exact Volume Conversions Matter
Volume is notoriously regional: US customary and imperial systems differ, and even within the US there are “legal” nutrition measures alongside traditional kitchenware. By deriving everything from exact bases—US gallon = 3.785411784 L, imperial gallon = 4.54609 L, 1 L = 1000 mL—you eliminate drift between recipe cards, labels, and procurement systems.
Core Relationships You’ll Use Daily
1 L = 1000 mL(exact)-
1 US gal = 3.785411784 L•1 US fl oz = 29.5735295625 mL(exact) -
1 imp gal = 4.54609 L•1 imp fl oz = 28.4130625 mL(exact) -
1 US pt = 473.176473 mL•1 imp pt = 568.26125 mL(exact) -
1 US cup = 236.5882365 mL•1 legal cup (US nutrition) = 240 mL•1 metric cup = 250 mL -
1 US tbsp = 14.78676478125 mL•1 US tsp = 4.92892159375 mL•metric tbsp = 15 mL•metric tsp = 5 mL
Rounding, Precision & Display Strategy
Keep internal math exact; round once on presentation or export. For consumer UIs, whole mL and one decimal in cups/fl oz typically suffice. For QA and SOPs, show 1–2 decimals (or more) consistent with instrument resolution. Always label your units in headers (e.g., “Volume (mL)”) and avoid mixing systems in a single column.
Data Modeling & Developer Tips
Normalize to milliliters or liters (volume_ml, volume_l) and derive the rest at the edges. Include a short “Methods” note in docs: exact constants, which cup/tbsp/tsp standard you use, and your rounding policy. Maintain a regression set of known pairs (e.g., 1 US cup = 236.5882365 mL; 1 imp pt = 568.26125 mL) and test both directions in CI.
Regional Variants & Pitfalls
US customary vs. imperial differences are substantial (e.g., pints and gallons). Within the US, nutrition labels may use the 240 mL “legal” cup, while cookware often follows the 236.588… mL cup. Metric spoons (15 mL/5 mL) differ slightly from US spoons. Always state the system and stick to it across pages, PDFs, and exports.
Common Use Cases
- Recipe scaling and international cookbooks (US ↔ metric cups, spoons, and fl oz)
- Nutrition and labeling (legal cup, SI liters/milliliters, rounding to policy)
- E-commerce packaging (bottle sizes in fl oz/mL, cross-border catalogs)
- Manufacturing & QA (lot tracking in liters; consumer docs in cups/fl oz)
- Education & labs (SI-centric: liters/milliliters with exact imperial references)
Worked Examples
Recipe: 2 US cups of milk → 2 × 236.5882365 = 473.176473 mL (exact), which also equals 1 US pint. For a quick card you may show 473 mL; document your rounding rule.
Cross-border spec: 16 US fl oz bottle → 16 × 29.5735295625 = 473.176473 mL. In imperial fl oz this is ≈ 16.6535 imp fl oz (not an even number—always confirm which ounce you publish).
Labeling: 1.5 L carton → in US gallons: 1.5 ÷ 3.785411784 = 0.396258 gal. For consumer signage, 0.40 gal is common; keep the precise value internally.
Frequently Asked Questions
What are the exact base definitions for US, imperial, and metric volume units?
Metric units are decimal: 1 L = 1000 mL (exact). US liquid gallon is exactly 231 cubic inches, which yields 1 US gallon = 3.785411784 L and 1 US fluid ounce = 29.5735295625 mL. The imperial gallon is exactly 4.54609 L, so 1 imperial fluid ounce = 28.4130625 mL. These exact anchors drive all our calculators.
Why are there multiple cup, tablespoon, and teaspoon sizes?
Cups and spoons vary by region and context. US customary cup is 236.5882365 mL; US ‘legal’ cup for nutrition is 240 mL; the metric cup is 250 mL. US tablespoon is 14.78676478125 mL and teaspoon is 4.92892159375 mL; metric spoonware often rounds to 15 mL and 5 mL respectively. Our tools label the system in the title to avoid mixups.
Should I store volume in milliliters or liters in my database?
Pick a single canonical unit—many apps store milliliters as integers to simplify arithmetic and avoid floating-point rounding. Convert to cups, fl oz, pints, or gallons at the edges for UI and exports. Document this policy so all services use the same math.
What’s the difference between US liquid and US dry measures?
US dry measures (e.g., dry pint, dry gallon) are defined from a different base and are not the same as liquid measures. Our pages here focus on liquid volume (mL, L, fl oz, cups, pints, gallons). For ingredients listed by volume but measured as mass, you need density.
Why do my recipe conversions disagree with my measuring cup?
Differences usually come from the cup standard (US customary vs. ‘legal’ nutrition cup vs. metric cup) and rounding. Confirm which standard your cup uses and apply the matching calculator. For professional documentation, state the system and rounding rule on the page.
How should I round for packaging and nutrition labels?
Compute with full precision and round once when you display or export. For consumer labels, whole milliliters or one decimal are typical; for lab and QA, show 1–2 decimals or more as your SOP specifies. Avoid double-rounding across DB/UI/export layers.
What are the exact pint and gallon relationships I should memorize?
US liquid: 1 gal = 128 fl oz = 8 pt = 3.785411784 L (exact); 1 pt = 473.176473 mL (exact). Imperial: 1 imp gal = 160 imp fl oz = 8 imp pt = 4.54609 L (exact); 1 imp pt = 568.26125 mL (exact).
Do tablespoons and teaspoons map exactly to cups?
In US customary, 1 cup = 16 tbsp and 1 tbsp = 3 tsp, so 1 cup = 48 tsp. Metric spoons are often standardized to 15 mL (tbsp) and 5 mL (tsp). When converting between US and metric spoons, state which system you’re using to prevent confusion.
When I convert fl oz to mL and back, why don’t I always get the same number?
Display rounding is the usual culprit. Keep full precision internally (the constants above are exact), then round once at output. Reversing a rounded value inevitably introduces small differences—this is expected and acceptable if you document your rounding policy.
How do I convert between mass and volume for ingredients?
You need density at the relevant temperature. Volume (mL, L) and mass (g, kg) are different physical quantities. For flour, sugar, oils, etc., consult a density table or use a specialized calculator that accepts density as an input.
Any accessibility and internationalization tips for volume displays?
Always include the unit in labels and table headers (e.g., “Volume (mL)”). Use locale-aware number formatting for decimals and thousands separators. Ensure contrast is strong in both light and dark modes, and avoid using unit icons without text alternatives.
What field names work best for analytics and exports?
Prefer explicit, unit-suffixed fields such as volume_ml, volume_l, volume_fl_oz_us, and volume_fl_oz_imp. Include a short methods note: “Exact constants; round once at presentation.” This keeps teams aligned across emails, PDFs, and CSVs.
Keep This Page Handy
Bookmark this category page for rapid access to every volume converter on MetricCalc. New tools will follow the same layout and rounding philosophy so you can switch systems without friction. If a unit pair is missing, tell us and we’ll add it with the same exacting standards.