# US tablespoons to US cups (tbsp to cup)

> Convert US tablespoons to US cups: 1 tbsp = 0.0625 cup. Exact conversion factor, formula, 22-row table and worked examples, with JSON API and MCP access.

- Page id: `tablespoons-to-cups` · Quantity: Volume (`volume`, base unit L) · Tool: `convert_units`
- Canonical page: https://tttkmbb.com/conversion/tablespoons-to-cups · This document: https://tttkmbb.com/conversion/tablespoons-to-cups.md · JSON: https://tttkmbb.com/conversion/tablespoons-to-cups.json (add `?value=` for a result)

## Formula

- `1 tbsp = 0.0625 cup`
- `US cups = US tablespoons × 0.0625`
- Reverse: `US tablespoons = US cups × 16`

The factor follows from the SI definitions of both units (NIST SP 811); values below are rounded to 6 significant figures, the API returns up to 12.

## Worked examples

- 5 tbsp = 0.3125 cup
- 12.5 tbsp = 0.78125 cup
- 100 tbsp = 6.25 cup

## Conversion table

| US tablespoons (tbsp) | US cups (cup) |
| --- | --- |
| 1 | 0.0625 |
| 2 | 0.125 |
| 3 | 0.1875 |
| 4 | 0.25 |
| 5 | 0.3125 |
| 6 | 0.375 |
| 7 | 0.4375 |
| 8 | 0.5 |
| 9 | 0.5625 |
| 10 | 0.625 |
| 15 | 0.9375 |
| 20 | 1.25 |
| 25 | 1.5625 |
| 30 | 1.875 |
| 40 | 2.5 |
| 50 | 3.125 |
| 75 | 4.6875 |
| 100 | 6.25 |
| 200 | 12.5 |
| 250 | 15.625 |
| 500 | 31.25 |
| 1000 | 62.5 |

## API

- `GET https://tttkmbb.com/api/v1/convert?value=5&from_unit=tbsp&to_unit=cup_us` → unified JSON envelope with `result.values.result`, `formula`, `factor`, `sources`, `freshness`
- MCP: server `https://tttkmbb.com/mcp`, tool `convert_units` with `{"value":5,"from_unit":"tbsp","to_unit":"cup_us"}`
- All volume units: https://tttkmbb.com/api/v1/units?quantity=volume · full converter: [Volume Converter](https://tttkmbb.com/conversion/volume.md)
- Authentication: none. Freshness: `static` (fixed conversion factors).

## FAQ

**How many US cups are in one tablespoon?**

1 tbsp = 0.0625 cup. The factor comes from the SI definitions of both units (NIST SP 811 / BIPM), so it is exact or correct to at least 10 significant figures.

**What is the formula to convert US tablespoons to US cups?**

Multiply the value in US tablespoons by 0.0625: US cups = US tablespoons × 0.0625. For example, 5 tbsp = 0.3125 cup.

**How do I convert US cups back to US tablespoons?**

Multiply by the inverse factor 16 (US tablespoons = US cups × 16), or use the US cups-to-US tablespoons page.

## Related conversions

- [US cups to US tablespoons](https://tttkmbb.com/conversion/cups-to-tablespoons.md) (reverse)
- [Liters to US gallons](https://tttkmbb.com/conversion/liters-to-gallons.md)
- [US gallons to Liters](https://tttkmbb.com/conversion/gallons-to-liters.md)
- [Milliliters to US fluid ounces](https://tttkmbb.com/conversion/ml-to-fl-oz.md)
- [US fluid ounces to Milliliters](https://tttkmbb.com/conversion/fl-oz-to-ml.md)
- [Liters to Milliliters](https://tttkmbb.com/conversion/liters-to-ml.md)
- [Milliliters to Liters](https://tttkmbb.com/conversion/ml-to-liters.md)
- [US cups to Milliliters](https://tttkmbb.com/conversion/cups-to-ml.md)
- [Milliliters to US cups](https://tttkmbb.com/conversion/ml-to-cups.md)

## Data Sources

- NIST Special Publication 811 – Guide for the Use of the International System of Units (SI), Appendix B conversion factors — https://www.nist.gov/pml/special-publication-811 (standard, retrieved 2026-09-24)
- BIPM – The International System of Units (SI Brochure, 9th edition) — https://www.bipm.org/en/publications/si-brochure (standard, retrieved 2026-09-24)
- Wikipedia – Conversion of units — https://en.wikipedia.org/wiki/Conversion_of_units (reference, retrieved 2026-09-24)