diff --git a/src/tools/duration-calculator/duration-calculator.service.test.ts b/src/tools/duration-calculator/duration-calculator.service.test.ts
new file mode 100644
index 000000000..9035587a0
--- /dev/null
+++ b/src/tools/duration-calculator/duration-calculator.service.test.ts
@@ -0,0 +1,313 @@
+import { describe, expect, it } from 'vitest';
+import { computeDuration } from './duration-calculator.service';
+
+const zeroResult = {
+  errors: [],
+  total: {
+    days: 0,
+    hours: 0,
+    iso8601Duration: 'P0Y0M0DT0H0M0S',
+    milliseconds: 0,
+    minutes: 0,
+    prettified: '0ms',
+    prettifiedColonNotation: '0:00',
+    prettifiedDaysColon: '00:00:00',
+    prettifiedHoursColon: '00:00:00',
+    prettifiedVerbose: '0 milliseconds',
+    seconds: 0,
+    weeks: 0,
+    years: 0,
+  },
+};
+
+describe('duration-calculator', () => {
+  describe('computeDuration', () => {
+    it('should compute correct sum/values', () => {
+      expect(computeDuration('')).to.deep.eq(zeroResult);
+      expect(computeDuration('0s')).to.deep.eq(zeroResult);
+      expect(computeDuration('3600s')).to.deep.eq({
+        errors: [],
+        total: {
+          days: 0.041666666666666664,
+          hours: 1,
+          iso8601Duration: 'P0Y0M0DT1H0M0S',
+          milliseconds: 3600000,
+          minutes: 60,
+          prettified: '1h',
+          prettifiedColonNotation: '1:00:00',
+          prettifiedDaysColon: '01:00:00',
+          prettifiedHoursColon: '01:00:00',
+          prettifiedVerbose: '1 hour',
+          seconds: 3600,
+          weeks: 0.005952380952380952,
+          years: 0.00011415525114155251,
+        },
+      });
+      expect(computeDuration('1h 20m')).to.deep.eq({
+        errors: [],
+        total: {
+          days: 0.05555555555555555,
+          hours: 1.3333333333333333,
+          iso8601Duration: 'P0Y0M0DT1H20M0S',
+          milliseconds: 4800000,
+          minutes: 80,
+          prettified: '1h 20m',
+          prettifiedColonNotation: '1:20:00',
+          prettifiedDaysColon: '01:20:00',
+          prettifiedHoursColon: '01:20:00',
+          prettifiedVerbose: '1 hour 20 minutes',
+          seconds: 4800,
+          weeks: 0.007936507936507936,
+          years: 0.00015220700152207003,
+        },
+      });
+      expect(computeDuration('01:02:03')).to.deep.eq({
+        errors: [],
+        total: {
+          days: 0.043090277777777776,
+          hours: 1.0341666666666667,
+          iso8601Duration: 'P0Y0M0DT1H2M3S',
+          milliseconds: 3723000,
+          minutes: 62.05,
+          prettified: '1h 2m 3s',
+          prettifiedColonNotation: '1:02:03',
+          prettifiedDaysColon: '01:02:03',
+          prettifiedHoursColon: '01:02:03',
+          prettifiedVerbose: '1 hour 2 minutes 3 seconds',
+          seconds: 3723,
+          weeks: 0.006155753968253968,
+          years: 0.00011805555555555556,
+        },
+      });
+      expect(computeDuration('-01:02:03')).to.deep.eq({
+        errors: [],
+        total: {
+          days: -0.043090277777777776,
+          hours: -1.0341666666666667,
+          iso8601Duration: 'P0Y0M0DT1H2M3S',
+          milliseconds: -3723000,
+          minutes: -62.05,
+          prettified: '-1h 2m 3s',
+          prettifiedColonNotation: '-1:02:03',
+          prettifiedDaysColon: '-2:-3:-3',
+          prettifiedHoursColon: '-2:-3:-3',
+          prettifiedVerbose: '-1 hour 2 minutes 3 seconds',
+          seconds: -3723,
+          weeks: -0.006155753968253968,
+          years: -0.00011805555555555556,
+        },
+      });
+      expect(computeDuration('+01:02:05')).to.deep.eq({
+        errors: [],
+        total: {
+          days: 0.04311342592592592,
+          hours: 1.0347222222222223,
+          iso8601Duration: 'P0Y0M0DT1H2M5S',
+          milliseconds: 3725000,
+          minutes: 62.083333333333336,
+          prettified: '1h 2m 5s',
+          prettifiedColonNotation: '1:02:05',
+          prettifiedDaysColon: '01:02:05',
+          prettifiedHoursColon: '01:02:05',
+          prettifiedVerbose: '1 hour 2 minutes 5 seconds',
+          seconds: 3725,
+          weeks: 0.006159060846560847,
+          years: 0.00011811897513952308,
+        },
+      });
+      expect(computeDuration('25s\n+02:40:00.125\n-10s')).to.deep.eq({
+        errors: [],
+        total: {
+          days: 0.11128616898148148,
+          hours: 2.6708680555555557,
+          iso8601Duration: 'P0Y0M0DT2H40M15S',
+          milliseconds: 9615125,
+          minutes: 160.25208333333333,
+          prettified: '2h 40m 15.1s',
+          prettifiedColonNotation: '2:40:15.1',
+          prettifiedDaysColon: '02:40:15.125',
+          prettifiedHoursColon: '02:40:15.125',
+          prettifiedVerbose: '2 hours 40 minutes 15.1 seconds',
+          seconds: 9615.125,
+          weeks: 0.01589802414021164,
+          years: 0.00030489361364789447,
+        },
+      });
+      expect(computeDuration('3d 25s\n+00:40:00\n-10s')).to.deep.eq({
+        errors: [],
+        total: {
+          days: 3.027951388888889,
+          hours: 72.67083333333333,
+          iso8601Duration: 'P0Y0M3DT0H40M15S',
+          milliseconds: 261615000,
+          minutes: 4360.25,
+          prettified: '3d 40m 15s',
+          prettifiedColonNotation: '3:00:40:15',
+          prettifiedDaysColon: '3d 00:40:15',
+          prettifiedHoursColon: '72:40:15',
+          prettifiedVerbose: '3 days 40 minutes 15 seconds',
+          seconds: 261615,
+          weeks: 0.4325644841269841,
+          years: 0.008295757229832572,
+        },
+      });
+      expect(computeDuration('25s\n+12:40\n-10s')).to.deep.eq({
+        errors: [],
+        total: {
+          days: 0.5279513888888889,
+          hours: 12.670833333333333,
+          iso8601Duration: 'P0Y0M0DT12H40M15S',
+          milliseconds: 45615000,
+          minutes: 760.25,
+          prettified: '12h 40m 15s',
+          prettifiedColonNotation: '12:40:15',
+          prettifiedDaysColon: '12:40:15',
+          prettifiedHoursColon: '12:40:15',
+          prettifiedVerbose: '12 hours 40 minutes 15 seconds',
+          seconds: 45615,
+          weeks: 0.07542162698412698,
+          years: 0.0014464421613394217,
+        },
+      });
+
+      expect(computeDuration('P4DT12H20M20.3S')).to.deep.eq({
+        errors: [],
+        total: {
+          days: 0.5138891238425926,
+          hours: 12.333338972222222,
+          iso8601Duration: 'P0Y0M0DT12H20M0S',
+          milliseconds: 44400020.3,
+          minutes: 740.0003383333333,
+          prettified: '12h 20m',
+          prettifiedColonNotation: '12:20:00',
+          prettifiedDaysColon: '12:20:00.20.299999997019768',
+          prettifiedHoursColon: '12:20:00.20.299999997019768',
+          prettifiedVerbose: '12 hours 20 minutes',
+          seconds: 44400.0203,
+          weeks: 0.07341273197751322,
+          years: 0.0014079154077879248,
+        },
+      });
+      expect(computeDuration('25s\n+PT20H\n-10s')).to.deep.eq({
+        errors: [],
+        total: {
+          days: 0.8335069444444444,
+          hours: 20.004166666666666,
+          iso8601Duration: 'P0Y0M0DT20H0M15S',
+          milliseconds: 72015000,
+          minutes: 1200.25,
+          prettified: '20h 15s',
+          prettifiedColonNotation: '20:00:15',
+          prettifiedDaysColon: '20:00:15',
+          prettifiedHoursColon: '20:00:15',
+          prettifiedVerbose: '20 hours 15 seconds',
+          seconds: 72015,
+          weeks: 0.11907242063492063,
+          years: 0.0022835806697108067,
+        },
+      });
+    });
+    it('should report invalid lines', () => {
+      expect(computeDuration('azerr')).to.deep.eq({
+        errors: [
+          'azerr',
+        ],
+        total: {
+          days: 0,
+          hours: 0,
+          iso8601Duration: 'P0Y0M0DT0H0M0S',
+          milliseconds: 0,
+          minutes: 0,
+          prettified: '0ms',
+          prettifiedColonNotation: '0:00',
+          prettifiedDaysColon: '00:00:00',
+          prettifiedHoursColon: '00:00:00',
+          prettifiedVerbose: '0 milliseconds',
+          seconds: 0,
+          weeks: 0,
+          years: 0,
+        },
+      });
+      expect(computeDuration('25s\ner\n-10s')).to.deep.eq({
+        errors: [
+          'er',
+        ],
+        total: {
+          days: 0.00017361111111111112,
+          hours: 0.004166666666666667,
+          iso8601Duration: 'P0Y0M0DT0H0M15S',
+          milliseconds: 15000,
+          minutes: 0.25,
+          prettified: '15s',
+          prettifiedColonNotation: '0:15',
+          prettifiedDaysColon: '00:00:15',
+          prettifiedHoursColon: '00:00:15',
+          prettifiedVerbose: '15 seconds',
+          seconds: 15,
+          weeks: 0.0000248015873015873,
+          years: 4.756468797564688e-7,
+        },
+      });
+      expect(computeDuration('25s\n+00:40:00\ner')).to.deep.eq({
+        errors: [
+          'er',
+        ],
+        total: {
+          days: 0.02806712962962963,
+          hours: 0.6736111111111112,
+          iso8601Duration: 'P0Y0M0DT0H40M25S',
+          milliseconds: 2425000,
+          minutes: 40.416666666666664,
+          prettified: '40m 25s',
+          prettifiedColonNotation: '40:25',
+          prettifiedDaysColon: '00:40:25',
+          prettifiedHoursColon: '00:40:25',
+          prettifiedVerbose: '40 minutes 25 seconds',
+          seconds: 2425,
+          weeks: 0.004009589947089947,
+          years: 0.00007689624556062913,
+        },
+      });
+      expect(computeDuration('ty\n+12:40\n-10s')).to.deep.eq({
+        errors: [
+          'ty',
+        ],
+        total: {
+          days: 0.5276620370370371,
+          hours: 12.66388888888889,
+          iso8601Duration: 'P0Y0M0DT12H39M50S',
+          milliseconds: 45590000,
+          minutes: 759.8333333333334,
+          prettified: '12h 39m 50s',
+          prettifiedColonNotation: '12:39:50',
+          prettifiedDaysColon: '12:39:50',
+          prettifiedHoursColon: '12:39:50',
+          prettifiedVerbose: '12 hours 39 minutes 50 seconds',
+          seconds: 45590,
+          weeks: 0.075380291005291,
+          years: 0.0014456494165398274,
+        },
+      });
+    });
+    it('support comment lines (#)', () => {
+      expect(computeDuration('25s\n # comment\n-10s')).to.deep.eq({
+        errors: [],
+        total: {
+          days: 0.00017361111111111112,
+          hours: 0.004166666666666667,
+          iso8601Duration: 'P0Y0M0DT0H0M15S',
+          milliseconds: 15000,
+          minutes: 0.25,
+          prettified: '15s',
+          prettifiedColonNotation: '0:15',
+          prettifiedDaysColon: '00:00:15',
+          prettifiedHoursColon: '00:00:15',
+          prettifiedVerbose: '15 seconds',
+          seconds: 15,
+          weeks: 0.0000248015873015873,
+          years: 4.756468797564688e-7,
+        },
+      });
+    });
+  });
+});
diff --git a/src/tools/duration-calculator/duration-calculator.service.ts b/src/tools/duration-calculator/duration-calculator.service.ts
new file mode 100644
index 000000000..395e1761d
--- /dev/null
+++ b/src/tools/duration-calculator/duration-calculator.service.ts
@@ -0,0 +1,127 @@
+import parse from 'parse-duration';
+import prettyMilliseconds from 'pretty-ms';
+import { formatISODuration, intervalToDuration } from 'date-fns';
+import * as iso8601Duration from 'duration-fns';
+
+interface ConvertedDuration {
+  prettified: string
+  prettifiedVerbose: string
+  prettifiedColonNotation: string
+  prettifiedDaysColon: string
+  prettifiedHoursColon: string
+  iso8601Duration: string
+  milliseconds: number
+  seconds: number
+  minutes: number
+  hours: number
+  days: number
+  weeks: number
+  years: number
+}
+
+interface DurationLine {
+  rawLine: string
+  cleanedDuration: string
+  sign: number
+  durationMS: number | undefined
+  isValid: boolean
+}
+
+export function computeDuration(s: string): {
+  total: ConvertedDuration
+  errors: string[]
+} {
+  const lines: DurationLine[] = s.split('\n').filter(l => l && !/^\s*#/.test(l)).map((l) => {
+    const isNeg = /^\s*\-/.test(l);
+    const cleanedDuration = l.replace(/^\s*[\+-]\s*/, '');
+    const durationMS = convertDurationMS(cleanedDuration);
+    return {
+      rawLine: l,
+      cleanedDuration,
+      sign: isNeg ? -1 : 1,
+      durationMS,
+      isValid: !(typeof durationMS === 'undefined'),
+    };
+  });
+
+  const sumMS = lines.map(l => ({ durationMS: l.durationMS || 0, sign: l.sign })).reduce(
+    (prev, curr) => ({
+      durationMS: prev.durationMS + curr.durationMS * curr.sign,
+      sign: 1,
+    }),
+    {
+      sign: 1,
+      durationMS: 0,
+    });
+
+  return {
+    total: prepareDurationResult(sumMS.durationMS),
+    errors: lines.filter(l => !l.isValid).map(l => l.rawLine),
+  };
+}
+
+function convertDurationMS(s: string): number | undefined {
+  const hoursHandled = s.replace(/\b(\d+):(\d+)(?::(\d+)(?:\.(\d+))?)?/g, (_, h, m, s, ms) => {
+    const timeArr: string[] = [];
+    const addPart = (part: string, unit: string) => {
+      const num = Number.parseInt(part, 10);
+      if (Number.isNaN(num)) {
+        return;
+      }
+
+      timeArr.push(`${num}${unit}`);
+    };
+    addPart(h, 'h');
+    addPart(m, 'm');
+    addPart(s, 's');
+    addPart(ms, 'ms');
+    return timeArr.join(' ');
+  });
+  if (!hoursHandled) {
+    return 0;
+  }
+
+  let parsedDuration = parse(hoursHandled);
+  if (parsedDuration !== 0 && !parsedDuration) {
+    try {
+      parsedDuration = iso8601Duration.toMilliseconds(iso8601Duration.parse(hoursHandled));
+    }
+    catch (_) {
+      return undefined;
+    }
+  }
+  return parsedDuration;
+}
+function prepareDurationResult(durationMS: any): ConvertedDuration {
+  const dateFnsDuration = intervalToDuration({ start: 0, end: durationMS });
+  return {
+    prettified: prettyMilliseconds(durationMS),
+    prettifiedVerbose: prettyMilliseconds(durationMS, { verbose: true }),
+    prettifiedColonNotation: prettyMilliseconds(durationMS, { colonNotation: true }),
+    prettifiedDaysColon: hhmmss(durationMS, true),
+    prettifiedHoursColon: hhmmss(durationMS, false),
+    iso8601Duration: formatISODuration(dateFnsDuration),
+    milliseconds: durationMS,
+    seconds: durationMS / 1000,
+    minutes: durationMS / (1000 * 60),
+    hours: durationMS / (1000 * 3600),
+    days: durationMS / (1000 * 86400),
+    weeks: durationMS / (1000 * 86400 * 7),
+    years: durationMS / (1000 * 86400 * 365),
+  };
+}
+
+function hhmmss(milliseconds: number, days: boolean) {
+  const padNumber = (n: number) => n.toString().padStart(2, '0');
+  const ms = milliseconds % 1000;
+  const seconds = milliseconds / 1000;
+  let h = Math.floor(seconds / 3600);
+  const m = Math.floor(seconds % 3600 / 60);
+  const s = Math.floor(seconds % 3600 % 60);
+  let d = 0;
+  if (days) {
+    d = Math.floor(h / 24);
+    h = h % 24;
+  }
+  return `${d > 0 ? `${d}d ` : ''}${padNumber(h)}:${padNumber(m)}:${padNumber(s)}${ms > 0 ? `.${ms}` : ''}`;
+}
diff --git a/src/tools/duration-calculator/duration-calculator.vue b/src/tools/duration-calculator/duration-calculator.vue
new file mode 100644
index 000000000..ba35b7fbd
--- /dev/null
+++ b/src/tools/duration-calculator/duration-calculator.vue
@@ -0,0 +1,43 @@
+<script setup lang="ts">
+import { computeDuration } from './duration-calculator.service';
+
+const inputDurations = ref('');
+const result = computed(() => computeDuration(inputDurations.value));
+const errors = computed(() => result.value.errors.map(l => l.rawLine).join('\n'));
+</script>
+
+<template>
+  <div>
+    <c-input-text
+      v-model:value="inputDurations"
+      multiline
+      rows="5"
+      label="Duration(s)"
+      placeholder="Please enter duration, one per line with optional sign"
+      mb-2
+    />
+    <n-p>Supports: comment (# line), HH:MM:SS.FFF, 3d 1h 3s..., P4DT12H20M20.3S..</n-p>
+
+    <n-divider />
+
+    <c-card title="Total">
+      <input-copyable label="Prettified" :value="result.total.prettified" />
+      <input-copyable label="Prettified (full)" :value="result.total.prettifiedVerbose" />
+      <input-copyable label="Prettified (colon)" :value="result.total.prettifiedColonNotation" />
+      <input-copyable label="Prettified (days)" :value="result.total.prettifiedDaysColon" />
+      <input-copyable label="Prettified (hours)" :value="result.total.prettifiedHoursColon" />
+      <input-copyable label="Prettified (ISO8601)" :value="result.total.iso8601Duration" />
+      <input-copyable label="Milliseconds" :value="result.total.milliseconds" />
+      <input-copyable label="Seconds" :value="result.total.seconds" />
+      <input-copyable label="Minutes" :value="result.total.minutes" />
+      <input-copyable label="Hours" :value="result.total.hours" />
+      <input-copyable label="Days" :value="result.total.days" />
+      <input-copyable label="Weeks" :value="result.total.weeks" />
+      <input-copyable label="Years" :value="result.total.years" />
+    </c-card>
+
+    <c-card title="Lines errors" mb-2>
+      <textarea-copyable :value="errors" />
+    </c-card>
+  </div>
+</template>
diff --git a/src/tools/duration-calculator/index.ts b/src/tools/duration-calculator/index.ts
new file mode 100644
index 000000000..0d2c7fed3
--- /dev/null
+++ b/src/tools/duration-calculator/index.ts
@@ -0,0 +1,12 @@
+import { CalendarTime } from '@vicons/tabler';
+import { defineTool } from '../tool';
+
+export const tool = defineTool({
+  name: 'Duration Calculator',
+  path: '/duration-calculator',
+  description: 'Calculate/parse durations',
+  keywords: ['duration', 'iso', '8601', 'time', 'calculator'],
+  component: () => import('./duration-calculator.vue'),
+  icon: CalendarTime,
+  createdAt: new Date('2024-08-15'),
+});
diff --git a/src/tools/index.ts b/src/tools/index.ts
index 52bdf8e37..a55143a39 100644
--- a/src/tools/index.ts
+++ b/src/tools/index.ts
@@ -1,6 +1,7 @@
 import { tool as base64FileConverter } from './base64-file-converter';
 import { tool as base64StringConverter } from './base64-string-converter';
 import { tool as basicAuthGenerator } from './basic-auth-generator';
+import { tool as durationCalculator } from './duration-calculator';
 import { tool as pdfSignatureChecker } from './pdf-signature-checker';
 import { tool as numeronymGenerator } from './numeronym-generator';
 import { tool as macAddressGenerator } from './mac-address-generator';
@@ -151,7 +152,12 @@ export const toolsByCategory: ToolCategory[] = [
   },
   {
     name: 'Measurement',
-    components: [chronometer, temperatureConverter, benchmarkBuilder],
+    components: [
+      chronometer,
+      temperatureConverter,
+	  durationCalculator,
+      benchmarkBuilder,
+    ],
   },
   {
     name: 'Text',