Both forms use 1 US tablespoon = 14.78676478125 mL. Tbsp to mL starts with a tablespoon amount; mL to tbsp starts with a milliliter amount. Both offer the reverse direction.
| Tbsp to mL | mL to tbsp | |
|---|---|---|
| Controls | One amount and direction selector | Direction selector with separate active mL or tbsp field |
| Default | 1 tbsp → 14.79 mL | 29.5735295625 mL → 2 US tbsp |
| Primary precision | Up to 2 decimals for mL; up to 4 for tbsp | Up to 12 decimals in either direction |
| Details | US factor and a separate 15 mL-per-spoon comparison | mL, US tablespoons and factor |
| Copy precision | Amount and mL up to 2 decimals; tbsp up to 4 | mL and tbsp up to 4 decimals |
Only the first form has the 15 mL comparison row. That alternate spoon size is not substituted into the US calculation, and it does not appear as a metric-spoon result on the mL-to-tbsp form.
Convert without early rounding
For a triple batch of 2.5 US tablespoons, calculate 2.5 × 14.78676478125 × 3 = 110.900735859375 mL, displayed as 110.9 mL with up to two decimal places. Rounding the single amount to 36.97 mL before multiplying gives 110.91 mL instead.
Limits
These forms convert volume to volume. No ingredient density is needed, and neither returns mass. Confirm the spoon definition on the source rather than assuming all household spoons have the same volume. Display and Copy precision differ; neither determines measuring accuracy or a substance’s appropriate use.
Sources
NIST SP 811, unit definitions and Appendix B factors. The paired calculator controls and rounding described above are their current form behavior. NIST Handbook 44, Appendix C, customary unit relationships.