Mass and Weight · Unit Converter

Convert Grain to Stone (US)

Convert grains to stones (us) instantly. 1 grain = 1.142857e-5 stone (us) — use the live calculator, the exact formula, a conversion table and worked examples. Also check the Stone (US) to Grain 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

Avoirdupois

Grain

What is a grain?

The grain (gr) equals 1/7000 of an avoirdupois pound, about 64.8 milligrams.

Origin of the grain

Based on the nominal mass of a single barley grain.

Where it is used

Ammunition and bullet mass, archery, and historical pharmacy.

When and where it was developed

Standardized through the English avoirdupois system and retained in 1959.

Avoirdupois

Stone (US)

What is a stone (us)?

A less common US definition of the stone, about 5.67 kilograms.

Origin of the stone (us)

A variant stone weight used in some historical US trade.

Where it is used

Rare; appears mainly in historical or specialized contexts.

When and where it was developed

Derived from older English stone weights that varied by commodity.

Grain to Stone (US) conversion formula

The relationship between grains and stones (us):

1 gr = 1.142857e-5 st
1 st = 87500.0135033157 gr

To convert grains to stones (us), multiply the value in grains by 1.142857e-5. To reverse, multiply stones (us) by 87500.0135033157.

How to use this converter

Type a value into the calculator. The result in stones (us) updates as you type. Tap a quick value, copy the result with one click, or use the swap arrow to jump straight to the Stone (US) to Grain converter for the reverse direction.

Step-by-step: convert grains to stones (us)

  1. Write down the value in grains (gr).
  2. Multiply that value by the factor 1.142857e-5.
  3. The product is the equivalent value in stones (us) (st).
  4. To reverse, multiply the stone (us) value by 87500.0135033157.

Worked examples

Example 1 — Convert 1 gr to st:
1 × 1.142857e-5 = 1.142857e-5 st

Example 2 — Convert 100 gr to st:
100 × 1.142857e-5 = 0.001142857 st

Real-world example — From microscopic to macroscopic

A million grains equals exactly one stone (us). This kind of conversion appears in microfluidics, where total channel length is given in stones (us) but feature widths are in grains.

1000000 gr × 1.142857e-5 = 11.4285696649 st

Real-world example — Macro-scale buildup

A million grains equals exactly one stone (us) — the conversion that bridges microscale features and macroscale objects in microfluidic, biomedical, and semiconductor packaging design.

1000000 gr × 1.142857e-5 = 11.4285696649 st

Real-world example — Quarter-meter measurement reference

A 250,000-grain length equals 0.25 stones (us) — useful for comparing supply-chain spec sheets where some lengths are quoted in the smaller unit and some in the larger.

250000 gr × 1.142857e-5 = 2.8571424162 st

Grain to Stone (US) conversion table

Standard reference values for converting grains to stones (us):

Grain [gr]Stone (US) [st]
0.011.142857e-7
0.11.142857e-6
11.142857e-5
22.285714e-5
33.428571e-5
44.571428e-5
55.714285e-5
100.0001142857
200.0002285714
300.0003428571
400.0004571428
500.0005714285
1000.001142857
5000.0057142848
10000.0114285697

Frequently asked questions

How many stones (us) is 1 grain?
1 grain equals 1.142857e-5 stone (us).
How do I convert grains to stones (us)?
Multiply the value in grains by 1.142857e-5 to get stones (us).
How do I convert stones (us) back to grains?
Multiply the value in stones (us) by 87500.0135033157, or use the Stone (US) to Grain converter.
How many stones (us) is 100 grains?
100 grains equals 0.001142857 stones (us), because 100 × 1.142857e-5 = 0.001142857.

Convert Grain to other weight units

Show all Grain conversions
Metric / SI (18 units)
Grain to Attogram (ag) Grain to Femtogram (fg) Grain to Picogram (pg) Grain to Nanogram (ng) Grain to Microgram (µg) Grain to Milligram (mg) Grain to Centigram (cg) Grain to Decigram (dg) Grain to Gram (g) Grain to Dekagram (dag) Grain to Hectogram (hg) Grain to Kilogram (kg) Grain to Quintal (metric) (q) Grain to Metric Ton (t) Grain to Gigagram (Gg) Grain to Teragram (Tg) Grain to Petagram (Pg) Grain to Exagram (Eg)
Avoirdupois (14 units)
Grain to Dram (avoirdupois) (dr) Grain to Ounce (oz) Grain to Pound (lb) Grain to Clove (clove) Grain to Stone (US) (st) Grain to Stone (UK) (st) Grain to Quarter (US) (qr) Grain to Quarter (UK) (qr) Grain to Hundredweight (US) (cwt) Grain to Hundredweight (UK) (cwt) Grain to Wey (wey) Grain to Kilopound (kip) (kip) Grain to Ton (short, US) (sh tn) Grain to Ton (long, UK) (long tn)
Troy & Apothecary (10 units)
Grain to Point (1/100 carat) (pt) Grain to Carat (metric) (ct) Grain to Scruple (apothecary) (s ap) Grain to Pennyweight (dwt) Grain to Momme (mom) Grain to Mace (mace) Grain to Dram (apothecary/troy) (dr ap) Grain to Troy Ounce (oz t) Grain to Tael (tael) Grain to Pound (troy/apothecary) (lb t)
Indian / South Asian (6 units)
Grain to Ratti (ratti) Grain to Masha (masha) Grain to Tola (tola) Grain to Chittack (Chatank) (chittack) Grain to Seer (Ser) (seer) Grain to Maund (Mann) (maund)
Scientific / Atomic (9 units)
Grain to Electron Mass (rest) (me) Grain to MeV/c2 (MeV/c²) Grain to Muon Mass (mµ) Grain to Atomic Mass Unit (u) Grain to Proton Mass (mp) Grain to Neutron Mass (mn) Grain to Deuteron Mass (md) Grain to Carbon-12 Atom Mass (C-12) Grain to Planck Mass (mP)
Astronomical (4 units)
Grain to Lunar Mass (Moon) (M☾) Grain to Earth's Mass (M⊕) Grain to Jupiter Mass (MJ) Grain to Sun's Mass (M☉)
Biblical / Ancient (14 units)
Grain to Lepton (Biblical Roman) (lepton) Grain to Quadrans (Biblical Roman) (quadrans) Grain to Assarion (Biblical Roman) (assarion) Grain to Gerah (Biblical Hebrew) (gerah) Grain to Drachma (Biblical Greek) (drachma) Grain to Denarius (Biblical Roman) (denarius) Grain to Bekan (Biblical Hebrew) (bekah) Grain to Didrachma (Biblical Greek) (didrachma) Grain to Shekel (Biblical Hebrew) (shekel) Grain to Tetradrachma (Biblical Greek) (tetra) Grain to Mina (Biblical Greek) (mina) Grain to Mina (Biblical Hebrew) (mina) Grain to Talent (Biblical Greek) (talent) Grain to Talent (Biblical Hebrew) (talent)
Force / Engineering (5 units)
Grain to Poundal (pdl) Grain to Ton (assay) (US) (AT) Grain to Ton (assay) (UK) (AT) Grain to Kilogram-force square second/meter (hyl) Grain to Slug (slug)

Sources & references

Conversion factor (1 gr = 1.142857e-5 st) verified against the following authoritative sources:

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