diff --git a/CHANGELOG.md b/CHANGELOG.md
index c6c3da03..220af176 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,10 @@
 # changes log
 
+## 7.3.0
+
+* Add `subset(r1, r2)` method to determine if `r1` range is entirely
+  contained by `r2` range.
+
 ## 7.2.3
 
 * Fix handling of `includePrelease` mode where version ranges like `1.0.0 -
diff --git a/README.md b/README.md
index ab408d3d..659201e2 100644
--- a/README.md
+++ b/README.md
@@ -79,6 +79,7 @@ const semverGtr = require('semver/ranges/gtr')
 const semverLtr = require('semver/ranges/ltr')
 const semverIntersects = require('semver/ranges/intersects')
 const simplifyRange = require('semver/ranges/simplify')
+const rangeSubset = require('semver/ranges/subset')
 ```
 
 As a command-line utility:
@@ -455,6 +456,8 @@ strings that they parse.
   programmatically, to provide the user with something a bit more
   ergonomic.  If the provided range is shorter in string-length than the
   generated range, then that is returned.
+* `subset(subRange, superRange)`: Return `true` if the `subRange` range is
+  entirely contained by the `superRange` range.
 
 Note that, since ranges may be non-contiguous, a version might not be
 greater than a range, less than a range, *or* satisfy a range!  For
diff --git a/classes/range.js b/classes/range.js
index 51125a01..cd87fb4d 100644
--- a/classes/range.js
+++ b/classes/range.js
@@ -92,6 +92,7 @@ class Range {
       .map(comp => parseComparator(comp, this.options))
       .join(' ')
       .split(/\s+/)
+      .map(comp => replaceGTE0(comp, this.options))
       // in loose mode, throw out any that are not valid comparators
       .filter(this.options.loose ? comp => !!comp.match(compRe) : () => true)
       .map(comp => new Comparator(comp, this.options))
@@ -379,6 +380,12 @@ const replaceStars = (comp, options) => {
   return comp.trim().replace(re[t.STAR], '')
 }
 
+const replaceGTE0 = (comp, options) => {
+  debug('replaceGTE0', comp, options)
+  return comp.trim()
+    .replace(re[options.includePrerelease ? t.GTE0PRE : t.GTE0], '')
+}
+
 // This function is passed to string.replace(re[t.HYPHENRANGE])
 // M, m, patch, prerelease, build
 // 1.2 - 3.4.5 => >=1.2.0 <=3.4.5
diff --git a/index.js b/index.js
index 54a714a3..57e2ae64 100644
--- a/index.js
+++ b/index.js
@@ -44,4 +44,5 @@ module.exports = {
   ltr: require('./ranges/ltr'),
   intersects: require('./ranges/intersects'),
   simplifyRange: require('./ranges/simplify'),
+  subset: require('./ranges/subset'),
 }
diff --git a/internal/re.js b/internal/re.js
index 0e8fb528..54d4176d 100644
--- a/internal/re.js
+++ b/internal/re.js
@@ -177,3 +177,6 @@ createToken('HYPHENRANGELOOSE', `^\\s*(${src[t.XRANGEPLAINLOOSE]})` +
 
 // Star ranges basically just allow anything at all.
 createToken('STAR', '(<|>)?=?\\s*\\*')
+// >=0.0.0 is like a star
+createToken('GTE0', '^\\s*>=\\s*0\.0\.0\\s*$')
+createToken('GTE0PRE', '^\\s*>=\\s*0\.0\.0-0\\s*$')
diff --git a/ranges/subset.js b/ranges/subset.js
new file mode 100644
index 00000000..6ae29a3c
--- /dev/null
+++ b/ranges/subset.js
@@ -0,0 +1,155 @@
+const Range = require('../classes/range.js')
+const { ANY } = require('../classes/comparator.js')
+const satisfies = require('../functions/satisfies.js')
+const compare = require('../functions/compare.js')
+
+// Complex range `r1 || r2 || ...` is a subset of `R1 || R2 || ...` iff:
+// - Every simple range `r1, r2, ...` is a subset of some `R1, R2, ...`
+//
+// Simple range `c1 c2 ...` is a subset of simple range `C1 C2 ...` iff:
+// - If c is only the ANY comparator
+//   - If C is only the ANY comparator, return true
+//   - Else return false
+// - Let EQ be the set of = comparators in c
+// - If EQ is more than one, return true (null set)
+// - Let GT be the highest > or >= comparator in c
+// - Let LT be the lowest < or <= comparator in c
+// - If GT and LT, and GT.semver > LT.semver, return true (null set)
+// - If EQ
+//   - If GT, and EQ does not satisfy GT, return true (null set)
+//   - If LT, and EQ does not satisfy LT, return true (null set)
+//   - If EQ satisfies every C, return true
+//   - Else return false
+// - If GT
+//   - If GT is lower than any > or >= comp in C, return false
+//   - If GT is >=, and GT.semver does not satisfy every C, return false
+// - If LT
+//   - If LT.semver is greater than that of any > comp in C, return false
+//   - If LT is <=, and LT.semver does not satisfy every C, return false
+// - If any C is a = range, and GT or LT are set, return false
+// - Else return true
+
+const subset = (sub, dom, options) => {
+  sub = new Range(sub, options)
+  dom = new Range(dom, options)
+  let sawNonNull = false
+
+  OUTER: for (const simpleSub of sub.set) {
+    for (const simpleDom of dom.set) {
+      const isSub = simpleSubset(simpleSub, simpleDom, options)
+      sawNonNull = sawNonNull || isSub !== null
+      if (isSub)
+        continue OUTER
+    }
+    // the null set is a subset of everything, but null simple ranges in
+    // a complex range should be ignored.  so if we saw a non-null range,
+    // then we know this isn't a subset, but if EVERY simple range was null,
+    // then it is a subset.
+    if (sawNonNull)
+      return false
+  }
+  return true
+}
+
+const simpleSubset = (sub, dom, options) => {
+  if (sub.length === 1 && sub[0].semver === ANY)
+    return dom.length === 1 && dom[0].semver === ANY
+
+  const eqSet = new Set()
+  let gt, lt
+  for (const c of sub) {
+    if (c.operator === '>' || c.operator === '>=')
+      gt = higherGT(gt, c, options)
+    else if (c.operator === '<' || c.operator === '<=')
+      lt = lowerLT(lt, c, options)
+    else
+      eqSet.add(c.semver)
+  }
+
+  if (eqSet.size > 1)
+    return null
+
+  let gtltComp
+  if (gt && lt) {
+    gtltComp = compare(gt.semver, lt.semver, options)
+    if (gtltComp > 0)
+      return null
+    else if (gtltComp === 0 && (gt.operator !== '>=' || lt.operator !== '<='))
+      return null
+  }
+
+  // will iterate one or zero times
+  for (const eq of eqSet) {
+    if (gt && !satisfies(eq, String(gt), options))
+      return null
+
+    if (lt && !satisfies(eq, String(lt), options))
+      return null
+
+    for (const c of dom) {
+      if (!satisfies(eq, String(c), options))
+        return false
+    }
+    return true
+  }
+
+  let higher, lower
+  let hasDomLT, hasDomGT
+  for (const c of dom) {
+    hasDomGT = hasDomGT || c.operator === '>' || c.operator === '>='
+    hasDomLT = hasDomLT || c.operator === '<' || c.operator === '<='
+    if (gt) {
+      if (c.operator === '>' || c.operator === '>=') {
+        higher = higherGT(gt, c, options)
+        if (higher === c)
+          return false
+      } else if (gt.operator === '>=' && !satisfies(gt.semver, String(c), options))
+        return false
+    }
+    if (lt) {
+      if (c.operator === '<' || c.operator === '<=') {
+        lower = lowerLT(lt, c, options)
+        if (lower === c)
+          return false
+      } else if (lt.operator === '<=' && !satisfies(lt.semver, String(c), options))
+        return false
+    }
+    if (!c.operator && (lt || gt) && gtltComp !== 0)
+      return false
+  }
+
+  // if there was a < or >, and nothing in the dom, then must be false
+  // UNLESS it was limited by another range in the other direction.
+  // Eg, >1.0.0 <1.0.1 is still a subset of <2.0.0
+  if (gt && hasDomLT && !lt && gtltComp !== 0)
+    return false
+
+  if (lt && hasDomGT && !gt && gtltComp !== 0)
+    return false
+
+  return true
+}
+
+// >=1.2.3 is lower than >1.2.3
+const higherGT = (a, b, options) => {
+  if (!a)
+    return b
+  const comp = compare(a.semver, b.semver, options)
+  return comp > 0 ? a
+    : comp < 0 ? b
+    : b.operator === '>' && a.operator === '>=' ? b
+    : a
+}
+
+// <=1.2.3 is higher than <1.2.3
+const lowerLT = (a, b, options) => {
+  if (!a)
+    return b
+  const comp = compare(a.semver, b.semver, options)
+  return comp < 0 ? a
+    : comp > 0 ? b
+    : b.operator === '<' && a.operator === '<=' ? b
+    : a
+}
+
+module.exports = subset
diff --git a/test/fixtures/range-parse.js b/test/fixtures/range-parse.js
index 65744c4b..be7feffd 100644
--- a/test/fixtures/range-parse.js
+++ b/test/fixtures/range-parse.js
@@ -58,7 +58,7 @@ module.exports = [
   ['~> 1', '>=1.0.0 <2.0.0'],
   ['~1.0', '>=1.0.0 <1.1.0'],
   ['~ 1.0', '>=1.0.0 <1.1.0'],
-  ['^0', '>=0.0.0 <1.0.0'],
+  ['^0', '<1.0.0'],
   ['^ 1', '>=1.0.0 <2.0.0'],
   ['^0.1', '>=0.1.0 <0.2.0'],
   ['^1.0', '>=1.0.0 <2.0.0'],
diff --git a/test/ranges/subset.js b/test/ranges/subset.js
new file mode 100644
index 00000000..586723fe
--- /dev/null
+++ b/test/ranges/subset.js
@@ -0,0 +1,75 @@
+const t = require('tap')
+const subset = require('../../ranges/subset.js')
+
+// sub, dom, expect, [options]
+const cases = [
+  ['1.2.3', '1.2.3', true],
+  ['1.2.3 1.2.4', '1.2.3', true],
+  ['1.2.3 2.3.4 || 2.3.4', '3', false],
+  ['^1.2.3-pre.0', '1.x', false],
+  ['^1.2.3-pre.0', '1.x', true, { includePrerelease: true }],
+  ['>2 <1', '3', true],
+  ['1 || 2 || 3', '>=1.0.0', true],
+
+  ['*', '*', true],
+  ['', '*', true],
+  ['*', '', true],
+  ['', '', true],
+
+  // >=0.0.0 is like * in non-prerelease mode
+  // >=0.0.0-0 is like * in prerelease mode
+  ['*', '>=0.0.0-0', true, { includePrerelease: true }],
+  ['*', '>=0.0.0', true],
+  ['*', '>=0.0.0', false, { includePrerelease: true }],
+  ['*', '>=0.0.0-0', false],
+  ['^2 || ^3 || ^4', '>=1', true],
+  ['^2 || ^3 || ^4', '>1', true],
+  ['^2 || ^3 || ^4', '>=2', true],
+  ['^2 || ^3 || ^4', '>=3', false],
+  ['>=1', '^2 || ^3 || ^4', false],
+  ['>1', '^2 || ^3 || ^4', false],
+  ['>=2', '^2 || ^3 || ^4', false],
+  ['>=3', '^2 || ^3 || ^4', false],
+  ['^1', '^2 || ^3 || ^4', false],
+  ['^2', '^2 || ^3 || ^4', true],
+  ['^3', '^2 || ^3 || ^4', true],
+  ['^4', '^2 || ^3 || ^4', true],
+  ['1.x', '^2 || ^3 || ^4', false],
+  ['2.x', '^2 || ^3 || ^4', true],
+  ['3.x', '^2 || ^3 || ^4', true],
+  ['4.x', '^2 || ^3 || ^4', true],
+
+  ['>=1.0.0 <=1.0.0 || 2.0.0', '1.0.0 || 2.0.0', true],
+  ['<=1.0.0 >=1.0.0 || 2.0.0', '1.0.0 || 2.0.0', true],
+  ['>=1.0.0', '1.0.0', false],
+  ['>=1.0.0 <2.0.0', '<2.0.0', true],
+  ['>=1.0.0 <2.0.0', '>0.0.0', true],
+  ['>=1.0.0 <=1.0.0', '1.0.0', true],
+  ['>=1.0.0 <=1.0.0', '2.0.0', false],
+  ['<2.0.0', '>=1.0.0 <2.0.0', false],
+  ['>=1.0.0', '>=1.0.0 <2.0.0', false],
+  ['>=1.0.0 <2.0.0', '<2.0.0', true],
+  ['>=1.0.0 <2.0.0', '>=1.0.0', true],
+  ['>=1.0.0 <2.0.0', '>1.0.0', false],
+  ['>=1.0.0 <=2.0.0', '<2.0.0', false],
+  ['>=1.0.0', '<1.0.0', false],
+  ['<=1.0.0', '>1.0.0', false],
+  ['<=1.0.0 >1.0.0', '>1.0.0', true],
+  ['1.0.0 >1.0.0', '>1.0.0', true],
+  ['1.0.0 <1.0.0', '>1.0.0', true],
+  ['<1 <2 <3', '<4', true],
+  ['<3 <2 <1', '<4', true],
+  ['>1 >2 >3', '>0', true],
+  ['>3 >2 >1', '>0', true],
+  ['<=1 <=2 <=3', '<4', true],
+  ['<=3 <=2 <=1', '<4', true],
+  ['>=1 >=2 >=3', '>0', true],
+  ['>=3 >=2 >=1', '>0', true],
+]
+
+t.plan(cases.length)
+cases.forEach(([sub, dom, expect, options = {}]) => {
+  const msg = `${sub || "''"} ⊂ ${dom || "''"} = ${expect}` +
+    (options ? ' ' + Object.keys(options).join(',') : '')
+  t.equal(subset(sub, dom, options), expect, msg)
+})