Mass and Weight · Unit Converter

Convert Femtogram to Dram (apothecary/troy)

Convert femtograms to drams (apothecary/troy) instantly. 1 femtogram = 2.57206e-16 dram (apothecary/troy) — use the live calculator, the exact formula, a conversion table and worked examples. Also check the Dram (apothecary/troy) to Femtogram converter for the reverse conversion.

Written by Sunith Babu L, Ph.D., Lead Engineer Reviewed by Dr. Ashok Kumar K, Ph.D.
Mass and Weight category 2 min read Published Last reviewed Updated

Units explained

Metric / SI

Femtogram

What is a femtogram?

A femtogram (fg) equals 10^-18 kilogram.

Origin of the femtogram

From the SI prefix 'femto-' (from Danish/Norwegian 'femten', fifteen).

Where it is used

Nanotechnology and high-sensitivity mass spectrometry.

When and where it was developed

The femto- prefix was adopted by the CGPM in 1975.

Troy & Apothecary

Dram (apothecary/troy)

What is a dram (apothecary/troy)?

The apothecary (troy) dram equals one-eighth of a troy ounce, about 3.888 grams.

Origin of the dram (apothecary/troy)

From the apothecaries' system rooted in the Greek 'drachma'.

Where it is used

Historical pharmacy and medicine compounding.

When and where it was developed

Part of the apothecaries' system of weights used through the 19th century.

Femtogram to Dram (apothecary/troy) conversion formula

The relationship between femtograms and drams (apothecary/troy):

1 fg = 2.57206e-16 dr ap
1 dr ap = 3.887935e+15 fg

To convert femtograms to drams (apothecary/troy), multiply the value in femtograms by 2.57206e-16. To reverse, multiply drams (apothecary/troy) by 3.887935e+15.

How to use this converter

Type a value into the calculator. The result in drams (apothecary/troy) updates as you type. Tap a quick value, copy the result with one click, or use the swap arrow to jump straight to the Dram (apothecary/troy) to Femtogram converter for the reverse direction.

Step-by-step: convert femtograms to drams (apothecary/troy)

  1. Write down the value in femtograms (fg).
  2. Multiply that value by the factor 2.57206e-16.
  3. The product is the equivalent value in drams (apothecary/troy) (dr ap).
  4. To reverse, multiply the dram (apothecary/troy) value by 3.887935e+15.

Worked examples

Example 1 — Convert 1 fg to dr ap:
1 × 2.57206e-16 = 2.57206e-16 dr ap

Example 2 — Convert 100 fg to dr ap:
100 × 2.57206e-16 = 2.57206e-14 dr ap

Real-world example — Sub-micron to millimeter

500,000 femtograms converts to a small everyday quantity in drams (apothecary/troy) — useful when relating optical-wavelength specifications to physical mounting hardware.

500000 fg × 2.57206e-16 = 1.28603e-10 dr ap

Real-world example — From wavelengths to millimeter-scale objects

A value of one million femtograms sounds vast at the atomic scale but converts to a small everyday quantity in drams (apothecary/troy) — useful when relating optical-wavelength specifications to physical mounting hardware.

1000000 fg × 2.57206e-16 = 2.57206e-10 dr ap

Femtogram to Dram (apothecary/troy) conversion table

Standard reference values for converting femtograms to drams (apothecary/troy):

Femtogram [fg]Dram (apothecary/troy) [dr ap]
0.012.57206e-18
0.12.57206e-17
12.57206e-16
25.144119e-16
37.716179e-16
41.028824e-15
51.28603e-15
102.57206e-15
205.144119e-15
307.716179e-15
401.028824e-14
501.28603e-14
1002.57206e-14
5001.28603e-13
10002.57206e-13

Frequently asked questions

How many drams (apothecary/troy) is 1 femtogram?
1 femtogram equals 2.57206e-16 dram (apothecary/troy).
How do I convert femtograms to drams (apothecary/troy)?
Multiply the value in femtograms by 2.57206e-16 to get drams (apothecary/troy).
How do I convert drams (apothecary/troy) back to femtograms?
Multiply the value in drams (apothecary/troy) by 3.887935e+15, or use the Dram (apothecary/troy) to Femtogram converter.
How many drams (apothecary/troy) is 100 femtograms?
100 femtograms equals 2.57206e-14 drams (apothecary/troy), because 100 × 2.57206e-16 = 2.57206e-14.

Convert Femtogram to other weight units

Show all Femtogram conversions
Metric / SI (17 units)
Femtogram to Attogram (ag) Femtogram to Picogram (pg) Femtogram to Nanogram (ng) Femtogram to Microgram (µg) Femtogram to Milligram (mg) Femtogram to Centigram (cg) Femtogram to Decigram (dg) Femtogram to Gram (g) Femtogram to Dekagram (dag) Femtogram to Hectogram (hg) Femtogram to Kilogram (kg) Femtogram to Quintal (metric) (q) Femtogram to Metric Ton (t) Femtogram to Gigagram (Gg) Femtogram to Teragram (Tg) Femtogram to Petagram (Pg) Femtogram to Exagram (Eg)
Avoirdupois (15 units)
Femtogram to Grain (gr) Femtogram to Dram (avoirdupois) (dr) Femtogram to Ounce (oz) Femtogram to Pound (lb) Femtogram to Clove (clove) Femtogram to Stone (US) (st) Femtogram to Stone (UK) (st) Femtogram to Quarter (US) (qr) Femtogram to Quarter (UK) (qr) Femtogram to Hundredweight (US) (cwt) Femtogram to Hundredweight (UK) (cwt) Femtogram to Wey (wey) Femtogram to Kilopound (kip) (kip) Femtogram to Ton (short, US) (sh tn) Femtogram to Ton (long, UK) (long tn)
Troy & Apothecary (10 units)
Femtogram to Point (1/100 carat) (pt) Femtogram to Carat (metric) (ct) Femtogram to Scruple (apothecary) (s ap) Femtogram to Pennyweight (dwt) Femtogram to Momme (mom) Femtogram to Mace (mace) Femtogram to Dram (apothecary/troy) (dr ap) Femtogram to Troy Ounce (oz t) Femtogram to Tael (tael) Femtogram to Pound (troy/apothecary) (lb t)
Indian / South Asian (6 units)
Femtogram to Ratti (ratti) Femtogram to Masha (masha) Femtogram to Tola (tola) Femtogram to Chittack (Chatank) (chittack) Femtogram to Seer (Ser) (seer) Femtogram to Maund (Mann) (maund)
Scientific / Atomic (9 units)
Femtogram to Electron Mass (rest) (me) Femtogram to MeV/c2 (MeV/c²) Femtogram to Muon Mass (mµ) Femtogram to Atomic Mass Unit (u) Femtogram to Proton Mass (mp) Femtogram to Neutron Mass (mn) Femtogram to Deuteron Mass (md) Femtogram to Carbon-12 Atom Mass (C-12) Femtogram to Planck Mass (mP)
Astronomical (4 units)
Femtogram to Lunar Mass (Moon) (M☾) Femtogram to Earth's Mass (M⊕) Femtogram to Jupiter Mass (MJ) Femtogram to Sun's Mass (M☉)
Biblical / Ancient (14 units)
Femtogram to Lepton (Biblical Roman) (lepton) Femtogram to Quadrans (Biblical Roman) (quadrans) Femtogram to Assarion (Biblical Roman) (assarion) Femtogram to Gerah (Biblical Hebrew) (gerah) Femtogram to Drachma (Biblical Greek) (drachma) Femtogram to Denarius (Biblical Roman) (denarius) Femtogram to Bekan (Biblical Hebrew) (bekah) Femtogram to Didrachma (Biblical Greek) (didrachma) Femtogram to Shekel (Biblical Hebrew) (shekel) Femtogram to Tetradrachma (Biblical Greek) (tetra) Femtogram to Mina (Biblical Greek) (mina) Femtogram to Mina (Biblical Hebrew) (mina) Femtogram to Talent (Biblical Greek) (talent) Femtogram to Talent (Biblical Hebrew) (talent)
Force / Engineering (5 units)
Femtogram to Poundal (pdl) Femtogram to Ton (assay) (US) (AT) Femtogram to Ton (assay) (UK) (AT) Femtogram to Kilogram-force square second/meter (hyl) Femtogram to Slug (slug)

Sources & references

Conversion factor (1 fg = 2.57206e-16 dr ap) verified against the following authoritative sources:

Results are provided for general reference. Verify critical measurements against an authoritative standard.