diff --git a/math.js b/math.js
index b490f88..03fe783 100644
--- a/math.js
+++ b/math.js
@@ -36,3 +36,12 @@ export const min = (a, b) => a < b ? a : b
 export const max = (a, b) => a > b ? a : b
 
 export const isNaN = Number.isNaN
+
+export const pow = Math.pow
+/**
+ * Base 10 exponential function. Returns the value of 10 raised to the power of pow.
+ *
+ * @param {number} exp
+ * @return {number}
+ */
+export const exp10 = exp => Math.pow(10, exp)
diff --git a/metric.js b/metric.js
new file mode 100644
index 0000000..ec1b331
--- /dev/null
+++ b/metric.js
@@ -0,0 +1,48 @@
+import * as math from './math.js'
+
+export const yotta = 1e24
+export const zetta = 1e21
+export const exa = 1e18
+export const peta = 1e15
+export const tera = 1e12
+export const giga = 1e9
+export const mega = 1e6
+export const kilo = 1e3
+export const hecto = 1e2
+export const deca = 10
+export const deci = .1
+export const centi = .01
+export const milli = 1e-3
+export const micro = 1e-6
+export const nano = 1e-9
+export const pico = 1e-12
+export const femto = 1e-15
+export const atto = 1e-18
+export const zepto = 1e-21
+export const yocto = 1e-24
+
+const prefixUp = ['', 'k', 'M', 'G', 'T', 'P', 'E', 'Z', 'Y']
+const prefixDown = ['', 'm', 'μ', 'n', 'p', 'f', 'a', 'z', 'y']
+
+/**
+ * @param {number} n
+ * @param {number} [baseMultiplier] Multiplier of the base (10^(3*baseMultiplier)). E.g. `convert(time, -3)` if time is already in milli seconds
+ * @return {{n:number,prefix:string}}
+ */
+export const prefix = (n, baseMultiplier = 0) => {
+  const nPow = math.log10(n)
+  let mult = 0
+  while (nPow < mult * 3 && baseMultiplier > -8) {
+    baseMultiplier--
+    mult--
+  }
+  while (nPow >= 3 + mult * 3 && baseMultiplier < 8) {
+    baseMultiplier++
+    mult++
+  }
+  const prefix = baseMultiplier < 0 ? prefixDown[-baseMultiplier] : prefixUp[baseMultiplier]
+  return {
+    n: math.round((mult > 0 ? n / math.exp10(mult * 3) : n * math.exp10(mult * -3)) * 1e12) / 1e12,
+    prefix
+  }
+}
diff --git a/metric.test.js b/metric.test.js
new file mode 100644
index 0000000..ec58302
--- /dev/null
+++ b/metric.test.js
@@ -0,0 +1,34 @@
+import * as t from './testing.js'
+import * as metric from './metric.js'
+
+/**
+ * @param {t.TestCase} tc
+ */
+export const testMetricPrefix = tc => {
+  t.compare(metric.prefix(1, -1), { n: 1, prefix: 'm' })
+  t.compare(metric.prefix(1.5), { n: 1.5, prefix: '' })
+  t.compare(metric.prefix(100.5), { n: 100.5, prefix: '' })
+  t.compare(metric.prefix(1000.5), { n: 1.0005, prefix: 'k' })
+  t.compare(metric.prefix(.3), { n: 300, prefix: 'm' })
+  t.compare(metric.prefix(.001), { n: 1, prefix: 'm' })
+  // up
+  t.compare(metric.prefix(10000), { n: 10, prefix: 'k' })
+  t.compare(metric.prefix(1e7), { n: 10, prefix: 'M' })
+  t.compare(metric.prefix(1e11), { n: 100, prefix: 'G' })
+  t.compare(metric.prefix(1e12 + 3), { n: (1e12 + 3) / 1e12, prefix: 'T' })
+  t.compare(metric.prefix(1e15), { n: 1, prefix: 'P' })
+  t.compare(metric.prefix(1e20), { n: 100, prefix: 'E' })
+  t.compare(metric.prefix(1e22), { n: 10, prefix: 'Z' })
+  t.compare(metric.prefix(1e24), { n: 1, prefix: 'Y' })
+  t.compare(metric.prefix(1e28), { n: 10000, prefix: 'Y' })
+  // down
+  t.compare(metric.prefix(.01), { n: 10, prefix: 'm' })
+  t.compare(metric.prefix(1e-4), { n: 100, prefix: 'μ' })
+  t.compare(metric.prefix(1e-9), { n: 1, prefix: 'n' })
+  t.compare(metric.prefix(1e-12), { n: 1, prefix: 'p' })
+  t.compare(metric.prefix(1e-14), { n: 10, prefix: 'f' })
+  t.compare(metric.prefix(1e-18), { n: 1, prefix: 'a' })
+  t.compare(metric.prefix(1e-21), { n: 1, prefix: 'z' })
+  t.compare(metric.prefix(1e-22), { n: 100, prefix: 'y' })
+  t.compare(metric.prefix(1e-30), { n: .000001, prefix: 'y' })
+}
diff --git a/test.js b/test.js
index ee0ea63..b04cfa5 100644
--- a/test.js
+++ b/test.js
@@ -22,6 +22,7 @@ import * as number from './number.test.js'
 import * as buffer from './buffer.test.js'
 import * as sort from './sort.test.js'
 import * as url from './url.test.js'
+import * as metric from './metric.test.js'
 
 import { isBrowser, isNode } from './environment.js'
 
@@ -52,7 +53,8 @@ runTests({
   number,
   buffer,
   sort,
-  url
+  url,
+  metric
 }).then(success => {
   /* istanbul ignore next */
   if (isNode) {
diff --git a/testing.js b/testing.js
index 0ec8af7..09ade85 100644
--- a/testing.js
+++ b/testing.js
@@ -13,6 +13,7 @@ import * as statistics from './statistics.js'
 import * as array from './array.js'
 import * as env from './environment.js'
 import * as json from './json.js'
+import * as time from './time.js'
 
 import { performance } from './isomorphic.js'
 
@@ -129,8 +130,8 @@ export const run = async (moduleName, name, f, i, numberOfTests) => {
     ? `     - ${window.location.href}?filter=\\[${i + 1}/${tc._seed === null ? '' : `&seed=${tc._seed}`}`
     : `\nrepeat: npm run test -- --filter "\\[${i + 1}/" ${tc._seed === null ? '' : `--seed ${tc._seed}`}`
   const timeInfo = (repeat && err === null)
-    ? ` - ${times.length} repititions in ${duration.toFixed(2)}ms (best: ${times[0].toFixed(2)}ms, worst: ${array.last(times).toFixed(2)}ms, median: ${statistics.median(times).toFixed(2)}ms, average: ${statistics.average(times).toFixed(2)}ms)`
-    : ` in ${duration.toFixed(2)}ms`
+    ? ` - ${times.length} repititions in ${time.humanizeDuration(duration)} (best: ${time.humanizeDuration(times[0])}, worst: ${time.humanizeDuration(array.last(times))}, median: ${time.humanizeDuration(statistics.median(times))}, average: ${time.humanizeDuration(statistics.average(times))})`
+    : ` in ${time.humanizeDuration(duration)}`
   if (err !== null) {
     /* istanbul ignore else */
     if (err.constructor === SkipError) {
@@ -190,7 +191,7 @@ export const measureTime = async (message, f) => {
     iterations++
   }
   const iterationsInfo = iterations > 1 ? `, ${iterations} repititions` : ''
-  log.print(log.PURPLE, message, log.GREY, ` ${(duration / iterations)}ms${iterationsInfo}`)
+  log.print(log.PURPLE, message, log.GREY, ` ${time.humanizeDuration(duration / iterations)}${iterationsInfo}`)
 }
 
 /**
@@ -411,7 +412,7 @@ export const runTests = async tests => {
   const success = successfulTests === numberOfTests
   /* istanbul ignore else */
   if (success) {
-    log.print(log.GREEN, log.BOLD, 'All tests successful!', log.GREY, log.UNBOLD, ` in ${(end - start).toFixed(2)}ms`)
+    log.print(log.GREEN, log.BOLD, 'All tests successful!', log.GREY, log.UNBOLD, ` in ${time.humanizeDuration(end - start)}`)
     /* istanbul ignore next */
     log.printImgBase64(nyanCatImage, 50)
   } else {
diff --git a/time.js b/time.js
index 31d072c..3c4c5f7 100644
--- a/time.js
+++ b/time.js
@@ -1,3 +1,29 @@
 
+import * as metric from './metric.js'
+import * as math from './math.js'
+
 export const getDate = () => new Date()
 export const getUnixTime = Date.now
+
+/**
+ * @param {number} d duration in milliseconds
+ * @return {string} humanized approximation of time
+ */
+export const humanizeDuration = d => {
+  if (d < 60000) {
+    const p = metric.prefix(d, -1)
+    return math.round(p.n * 100) / 100 + p.prefix + 's'
+  }
+  d = math.floor(d / 1000)
+  const seconds = d % 60
+  const minutes = math.floor(d / 60) % 60
+  const hours = math.floor(d / 3600) % 24
+  const days = math.floor(d / 86400)
+  if (days > 0) {
+    return days + 'd' + (hours > 0 ? ' ' + (minutes > 30 ? hours + 1 : hours) + 'h' : '')
+  }
+  if (hours > 0 ) {
+    return hours + 'h' + (minutes > 0 ? ' ' + (seconds > 30 ? minutes + 1 : minutes) + 'min' : '')
+  }
+  return minutes + 'min' + (seconds > 0 ? ' ' + seconds + 's' : '')
+}
diff --git a/time.test.js b/time.test.js
index 6a75c99..96fa733 100644
--- a/time.test.js
+++ b/time.test.js
@@ -10,3 +10,19 @@ export const testTime = tc => {
   const r = time.getUnixTime()
   t.assert(math.abs(l - r) < 10, 'Times generated are roughly the same')
 }
+
+/**
+ * @param {t.TestCase} tc
+ */
+export const testHumanDuration = tc => {
+  t.assert(time.humanizeDuration(10) === '10ms')
+  t.assert(time.humanizeDuration(.1) === '100μs')
+  t.assert(time.humanizeDuration(61030) === '1min 1s')
+  t.assert(time.humanizeDuration(60030) === '1min')
+  t.assert(time.humanizeDuration(3600001) === '1h')
+  t.assert(time.humanizeDuration(3660000) === '1h 1min')
+  t.assert(time.humanizeDuration(3600000 * 25) === '1d 1h')
+  t.assert(time.humanizeDuration(3600000 * 24 * 400) === '400d')
+  // test round
+  t.assert(time.humanizeDuration(6001) === '6s')
+}