# Scruples to Pennyweights (s ap to dwt)

Source: https://www.unitconvertercalculator.com/weight/scruples-to-pennyweights/

**1 s ap = 0.83333333333333 dwt**

One scruple equals exactly 5/6 of a pennyweight, or approximately 0.8333 pennyweights. This clean fractional relationship arises from their shared grain foundation: 20 grains per scruple divided by 24 grains per pennyweight gives the exact ratio of 5 to 6. The scruple comes from apothecary pharmacy; the pennyweight from troy precious metals trading.

## Formula

Apply the conversion factor

## Conversion Table

| Scruples (s ap) | Pennyweights (dwt) |
|---|---|
| 0.5 s ap | 0.41666666666667 dwt |
| 1 s ap | 0.83333333333333 dwt |
| 3 s ap | 2.5 dwt |
| 5 s ap | 4.1666666666667 dwt |
| 10 s ap | 8.3333333333333 dwt |
| 20 s ap | 16.666666666667 dwt |
| 24 s ap | 20 dwt |
| 50 s ap | 41.666666666667 dwt |
| 100 s ap | 83.333333333333 dwt |
| 200 s ap | 166.66666666667 dwt |
| 288 s ap | 240 dwt |
| 500 s ap | 416.66666666667 dwt |
| 1000 s ap | 833.33333333333 dwt |

## Units

### Scruple (s ap)

An apothecary scruple equals 20 grains or 1/3 of a dram apothecary (1.2959782 grams). A historical pharmaceutical unit largely replaced by metric measurements.

### Pennyweight (dwt)

A pennyweight is a unit of mass equal to 24 grains or 1/20 of a troy ounce (1.55517384 grams). Used in the jewelry trade for weighing precious metals.

## Background

The scruple and pennyweight met in the workshops of goldsmiths who also prepared medicinal gold compounds. A goldsmith weighing gold leaf for dental fillings might use pennyweights, then switch to scruples when the same gold became an ingredient in a pharmaceutical preparation. The 5:6 ratio made such conversions straightforward.

## Good to Know

The 5:6 scruple-pennyweight ratio is one of the few mathematically elegant cross-system conversions in English measurement. It exists because both the apothecary and troy systems were built on the same grain, unlike the avoirdupois system which defined its grain independently. This shared foundation gave pharmacy and precious metals trading a common language at the smallest level, even as their larger units diverged.

## FAQ

### How many pennyweights are in one scruple?

One scruple equals exactly 5/6 of a pennyweight (approximately 0.8333 dwt). This exact fraction arises because the scruple is 20 grains and the pennyweight is 24 grains, giving 20/24 = 5/6.

### Why is this ratio so clean?

Both units are defined as exact multiples of the same grain (64.799 mg). Since 20 and 24 share a common factor of 4, the ratio simplifies to the elegant fraction 5/6. This mathematical relationship made conversions between apothecary and troy systems unusually simple.

### How do I convert scruples to pennyweights?

Multiply scruples by 0.8333 (or equivalently, multiply by 5 and divide by 6). For example, 6 scruples equals exactly 5 pennyweights. For 12 scruples, you get exactly 10 pennyweights.

## Non-Frequently Asked Questions

### Is 5/6 the most elegant fraction in weight conversion?

It is certainly one of the most satisfying. Cross-system conversions typically produce ugly decimals (like 0.04571 or 28.3495), but the scruple-pennyweight ratio of exactly 5/6 is clean enough to calculate on a medieval abacus. The fact that both units share the grain as their atomic unit makes this mathematical harmony possible.

### If I have 6 scruples of moral hesitation, do I have 5 pennyweights of ethical doubt?

At the apothecary-troy exchange rate, yes. Six scruples of anything convert to exactly five pennyweights, whether that anything is pharmaceutical powder, moral uncertainty, or hypothetical precious metal. The 5:6 ratio is the most democratic conversion factor on this website: it treats all substances equally.

### Did any historical figure work with both scruples and pennyweights?

Goldsmith-apothecaries were a real profession in medieval and early modern Europe. These dual practitioners prepared gold-based medicines, made dental prosthetics from precious metals, and gilded pharmaceutical containers. They would have converted between scruples and pennyweights as a routine part of their multidisciplinary craft.

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## See Also

- [Pennyweights to Scruples](https://www.unitconvertercalculator.com/weight/pennyweights-to-scruples/)