Legg til tre nye kalkulatorer: sparing, bolig og arv

Nye interaktive kalkulatorer som utforsker hvordan tilsynelatende
små forskjeller vokser eksponentielt over tid:

- sparing: rentes rente med ulik avkastning (månedlig compounding)
- bolig: belåningseffekt forsterker egenkapitalgap ~6.7×
- arv: arvet formue vokser uavhengig av innsats, gapet lukkes aldri

Landingsside oppdatert med nye kort. Dokumentasjon oppdatert.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
This commit is contained in:
Ole-Morten Duesund 2026-03-13 13:38:25 +01:00
commit 3ffb404250
13 changed files with 2194 additions and 37 deletions

195
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// Formateringshjelpere — norsk locale
function fmtKr(n) {
return Math.round(n).toLocaleString('nb-NO') + '\u202fkr';
}
function fmtShort(n) {
if (n >= 1e6) return (n / 1e6).toFixed(1).replace('.', ',') + '\u202fM';
if (n >= 1e3) return Math.round(n / 1e3) + '\u202fk';
return Math.round(n);
}
// Fremtidig verdi av annuitet med månedlig compounding
function futureValue(P, annualRate, years) {
const n = years * 12;
if (annualRate === 0) return P * n;
const r = annualRate / 12;
return P * (Math.pow(1 + r, n) - 1) / r;
}
function getData() {
const inheritance = +document.getElementById('inheritance').value;
const P = +document.getElementById('monthly').value;
const rate = +document.getElementById('rate').value / 100;
const Y = +document.getElementById('yrs').value;
const labels = [], wealthA = [], wealthB = [], gaps = [], arvPct = [];
for (let y = 0; y <= Y; y++) {
labels.push(y === 0 ? 'I dag' : (y % 5 === 0 || Y <= 10 || y === Y) ? 'År ' + y : '');
// A = ren annuitet (starter fra null)
const a = futureValue(P, rate, y);
// B = arv med rentes rente + samme annuitet
const arvGrown = inheritance * Math.pow(1 + rate, y);
const b = arvGrown + futureValue(P, rate, y);
// Gap = Arv × (1+r)^n — vokser alltid
const gap = arvGrown;
wealthA.push(a);
wealthB.push(b);
gaps.push(gap);
// Arvens andel av Bs formue (prosent)
arvPct.push(b > 0 ? (arvGrown / b) * 100 : 0);
}
return { inheritance, P, rate, Y, labels, wealthA, wealthB, gaps, arvPct };
}
const GRID_COLOR = 'rgba(0,0,0,0.06)';
const TICK_COLOR = '#8a857e';
function baseOpts() {
return {
responsive: true, maintainAspectRatio: false,
plugins: {
legend: { display: false },
tooltip: {
callbacks: { label: c => ' ' + fmtKr(c.parsed.y) },
backgroundColor: '#1a1714',
titleColor: '#f5f2eb',
bodyColor: 'rgba(245,242,235,0.7)',
padding: 10,
cornerRadius: 4,
titleFont: { family: 'DM Sans', size: 12 },
bodyFont: { family: 'DM Sans', size: 12 }
}
},
scales: {
x: {
ticks: { color: TICK_COLOR, font: { size: 11, family: 'DM Sans' }, autoSkip: false, maxRotation: 0 },
grid: { display: false },
border: { color: 'rgba(0,0,0,0.1)' }
},
y: {
ticks: { color: TICK_COLOR, font: { size: 11, family: 'DM Sans' }, callback: v => fmtShort(v) },
grid: { color: GRID_COLOR },
border: { dash: [3, 3], color: 'transparent' }
}
}
};
}
// Tilpasset y-akse for prosentdiagram
function pctOpts() {
const opts = baseOpts();
opts.scales.y.min = 0;
opts.scales.y.max = 100;
opts.scales.y.ticks = {
color: TICK_COLOR,
font: { size: 11, family: 'DM Sans' },
callback: v => v + ' %'
};
opts.plugins.tooltip.callbacks = {
label: c => ' ' + c.parsed.y.toFixed(1) + ' %'
};
return opts;
}
// Diagram 1: Formue over tid
const chart1 = new Chart(document.getElementById('chart1'), {
type: 'line',
data: { labels: [], datasets: [
{ data: [], borderColor: '#1a4a8a', backgroundColor: 'rgba(26,74,138,0.07)', fill: true, tension: 0.35, pointRadius: 0, borderWidth: 2 },
{ data: [], borderColor: '#c0392b', backgroundColor: 'rgba(192,57,43,0.07)', fill: true, tension: 0.35, pointRadius: 0, borderWidth: 2 }
]},
options: baseOpts()
});
// Diagram 2: Absolutt forskjell (gap)
const chart2 = new Chart(document.getElementById('chart2'), {
type: 'line',
data: { labels: [], datasets: [
{ data: [], borderColor: '#4a3a8a', backgroundColor: 'rgba(74,58,138,0.1)', fill: true, tension: 0.35, pointRadius: 0, borderWidth: 2 }
]},
options: baseOpts()
});
// Diagram 3: Arvens andel av Bs formue (prosent — tilpasset y-akse)
const chart3 = new Chart(document.getElementById('chart3'), {
type: 'line',
data: { labels: [], datasets: [
{ data: [], borderColor: '#b5620a', backgroundColor: 'rgba(181,98,10,0.1)', fill: true, tension: 0.35, pointRadius: 0, borderWidth: 2 }
]},
options: pctOpts()
});
// SIKKERHETSNOTAT: Alle verdier er beregnet fra numeriske slider-verdier.
// Ingen bruker-tekstinput brukes i DOM-oppdateringer.
function update() {
const { inheritance, P, rate, Y, labels, wealthA, wealthB, gaps, arvPct } = getData();
// Slider-visning
document.querySelectorAll('.yr-lbl').forEach(el => el.textContent = Y);
document.getElementById('inheritance-out').textContent = Math.round(inheritance).toLocaleString('nb-NO') + '\u202fkr';
document.getElementById('monthly-out').textContent = Math.round(P).toLocaleString('nb-NO') + '\u202fkr';
document.getElementById('rate-out').textContent = (rate * 100).toLocaleString('nb-NO', { minimumFractionDigits: 1 }) + '\u202f%';
document.getElementById('yrs-out').textContent = Y + '\u202får';
// Statistikkort
document.getElementById('st-valA').textContent = fmtKr(wealthA[Y]);
document.getElementById('st-valB').textContent = fmtKr(wealthB[Y]);
document.getElementById('st-subB').textContent = 'herav ' + fmtKr(gaps[Y]) + ' fra arv';
document.getElementById('st-gap').textContent = fmtKr(gaps[Y]);
const multiplier = (gaps[Y] / inheritance).toFixed(1).replace('.', ',');
document.getElementById('st-gap-sub').textContent = multiplier + '× opprinnelig arv';
document.getElementById('st-grown').textContent = fmtKr(gaps[Y]);
document.getElementById('st-grown-sub').textContent = 'fra ' + fmtKr(inheritance);
// Banner
document.getElementById('banner-gap').textContent = fmtKr(gaps[Y]);
// Innsikt — bruker DOM-metoder for sikkerhet
const insightEl = document.getElementById('insight');
insightEl.textContent = '';
const parts = [
{ text: 'A sparte like mye som B i ' + Y + ' år. Men arven på ' },
{ text: fmtKr(inheritance), bold: true },
{ text: ' har vokst til ' },
{ text: fmtKr(gaps[Y]), bold: true },
{ text: ' — og gapet kan aldri lukkes.' }
];
parts.forEach(p => {
if (p.bold) {
const strong = document.createElement('strong');
strong.textContent = p.text;
insightEl.appendChild(strong);
} else {
insightEl.appendChild(document.createTextNode(p.text));
}
});
// Diagram 1: Formue
chart1.data.labels = labels;
chart1.data.datasets[0].data = wealthA;
chart1.data.datasets[1].data = wealthB;
chart1.update('none');
// Diagram 2: Absolutt gap
chart2.data.labels = labels;
chart2.data.datasets[0].data = gaps;
chart2.update('none');
// Diagram 3: Arvens prosentandel
chart3.data.labels = labels;
chart3.data.datasets[0].data = arvPct;
chart3.update('none');
}
['inheritance', 'monthly', 'rate', 'yrs'].forEach(id =>
document.getElementById(id).addEventListener('input', update)
);
update();

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<!DOCTYPE html>
<html lang="nb">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Arvens forsprang — interaktiv kalkulator</title>
<link rel="preconnect" href="https://fonts.googleapis.com">
<link href="https://fonts.googleapis.com/css2?family=Fraunces:ital,opsz,wght@0,9..144,300;0,9..144,600;1,9..144,300&family=DM+Sans:wght@300;400;500&display=swap" rel="stylesheet">
<link rel="stylesheet" href="style.css">
<script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/4.4.1/chart.umd.js"></script>
</head>
<body>
<header>
<p class="eyebrow">Lik innsats. Ulikt utgangspunkt.</p>
<h1>Arvens<br><em>forsprang</em></h1>
<p class="lead">Person A starter fra null. Person B arver en sum. Begge sparer likt — men gapet lukkes aldri. Se hvordan arv forsterkes over tid.</p>
<div class="stamp">Ulik startlinje</div>
</header>
<div class="small-diff-banner">
<span class="sd-icon"></span>
<span>En arv på <strong>500 000 kr</strong> vokser til over <strong id="banner-gap"></strong> på 30 år — uten at B løfter en finger.</span>
</div>
<main>
<div class="controls-card">
<h2>Sjekk selv</h2>
<div class="controls-grid">
<div class="control-group">
<label>Arvebeløp (B mottar)</label>
<div class="val-row">
<input type="range" id="inheritance" min="100000" max="3000000" step="50000" value="500000">
<span class="val-display" id="inheritance-out">500 000 kr</span>
</div>
</div>
<div class="control-group">
<label>Månedlig sparing (begge)</label>
<div class="val-row">
<input type="range" id="monthly" min="1000" max="20000" step="500" value="3000">
<span class="val-display" id="monthly-out">3 000 kr</span>
</div>
</div>
<div class="control-group">
<label>Årlig avkastning (%)</label>
<div class="val-row">
<input type="range" id="rate" min="1" max="12" step="0.5" value="7">
<span class="val-display" id="rate-out">7,0 %</span>
</div>
</div>
<div class="control-group">
<label>Antall år</label>
<div class="val-row">
<input type="range" id="yrs" min="5" max="40" step="1" value="30">
<span class="val-display" id="yrs-out">30 år</span>
</div>
</div>
</div>
</div>
<div class="stat-strip">
<div class="stat">
<div class="stat-label">Formue A etter <span class="yr-lbl">30</span> år</div>
<div class="stat-value" id="st-valA"></div>
<div class="stat-sub" id="st-subA">startet fra null</div>
</div>
<div class="stat">
<div class="stat-label">Formue B etter <span class="yr-lbl">30</span> år</div>
<div class="stat-value" id="st-valB"></div>
<div class="stat-sub" id="st-subB"></div>
</div>
<div class="stat stat-diff">
<div class="stat-label">B har mer (= arv med renter)</div>
<div class="stat-value" id="st-gap" style="color:var(--accent);"></div>
<div class="stat-sub" id="st-gap-sub"></div>
</div>
<div class="stat">
<div class="stat-label">Arven har vokst til</div>
<div class="stat-value" id="st-grown" style="color:var(--purple);"></div>
<div class="stat-sub" id="st-grown-sub"></div>
</div>
</div>
<!-- Diagram 1: Formue over tid -->
<div class="chart-section">
<div class="chart-header">
<div>
<div class="chart-title">Formue over tid</div>
<div class="chart-desc">A sparer fra null, B starter med arv — begge sparer likt</div>
</div>
<div class="legend">
<span><span class="swatch" style="background:#1a4a8a;"></span>Person A</span>
<span><span class="swatch" style="background:#c0392b;"></span>Person B</span>
</div>
</div>
<div class="chart-wrap h-240"><canvas id="chart1"></canvas></div>
</div>
<!-- Diagram 2: Absolutt forskjell -->
<div class="chart-section">
<div class="chart-header">
<div>
<div class="chart-title">Absolutt forskjell</div>
<div class="chart-desc">Gapet = arven med rentes rente — vokser alltid</div>
</div>
<div class="legend">
<span><span class="swatch" style="background:#4a3a8a;"></span>Gap (arv × (1+r)ⁿ)</span>
</div>
</div>
<div class="chart-wrap h-200"><canvas id="chart2"></canvas></div>
</div>
<div class="insight" id="insight"></div>
<!-- Diagram 3: Arvens andel av Bs formue (prosent) -->
<div class="chart-section">
<div class="chart-header">
<div>
<div class="chart-title">Arvens andel av Bs formue</div>
<div class="chart-desc">Andelen synker over tid, men det absolutte beløpet vokser alltid</div>
</div>
<div class="legend">
<span><span class="swatch" style="background:#b5620a;"></span>Arv-andel (%)</span>
</div>
</div>
<div class="chart-wrap h-200"><canvas id="chart3"></canvas></div>
</div>
<!-- Forklaring -->
<div class="explainer">
<h3>Arvet formue vokser av seg selv</h3>
<p>Når B arver en sum, vokser den med rentes rente — helt uavhengig av innsats. A kan spare like mye, like lenge, med samme avkastning — men vil <strong>aldri</strong> ta igjen forskjellen.</p>
<div class="formula-box">
Gap = <span>Arv × (1 + r)ⁿ</span><br>
Gapet vokser eksponentielt, uavhengig av spareinnsats
</div>
<p>Over tid utgjør arven en stadig mindre <em>andel</em> av Bs totale formue — fordi egne sparepenger også vokser. Men det absolutte gapet øker alltid. Lik innsats gir aldri lik formue når startlinjen er ulik.</p>
</div>
</main>
<footer>
<a href="../">← Alle kalkulatorer</a> · Laget med Chart.js · Tallene er illustrative og ikke finansiell rådgivning · <a href="https://kode.naiv.no/olemd/forskjeller.naiv.no">Kildekode</a>
</footer>
<script src="app.js"></script>
</body>
</html>

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*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
:root {
--bg: #f5f2eb;
--bg2: #ede9e0;
--bg3: #e4dfd3;
--ink: #1a1714;
--ink2: #5a5650;
--ink3: #8a857e;
--accent: #c0392b;
--accent2: #2c6e49;
--blue: #1a4a8a;
--amber: #b5620a;
--purple: #4a3a8a;
--border: rgba(26,23,20,0.12);
--radius: 4px;
}
html { scroll-behavior: smooth; }
body {
font-family: 'DM Sans', sans-serif;
background: var(--bg);
color: var(--ink);
font-size: 16px;
line-height: 1.6;
min-height: 100vh;
}
/* HEADER */
header {
background: var(--ink);
color: var(--bg);
padding: 3.5rem 2rem 3rem;
text-align: center;
position: relative;
overflow: hidden;
}
header::before {
content: '';
position: absolute;
inset: 0;
background: repeating-linear-gradient(
-45deg,
transparent,
transparent 40px,
rgba(255,255,255,0.02) 40px,
rgba(255,255,255,0.02) 41px
);
}
header .eyebrow {
font-size: 11px;
letter-spacing: 0.18em;
text-transform: uppercase;
color: rgba(245,242,235,0.5);
margin-bottom: 1rem;
font-weight: 400;
}
header h1 {
font-family: 'Fraunces', serif;
font-size: clamp(2.2rem, 6vw, 4rem);
font-weight: 600;
line-height: 1.1;
margin-bottom: 1rem;
position: relative;
}
header h1 em {
font-style: italic;
color: #e8b4a0;
}
header p.lead {
font-size: clamp(0.95rem, 2vw, 1.1rem);
color: rgba(245,242,235,0.65);
max-width: 560px;
margin: 0 auto;
font-weight: 300;
line-height: 1.7;
}
/* MAIN LAYOUT */
main {
max-width: 900px;
margin: 0 auto;
padding: 2.5rem 1.25rem 4rem;
}
/* CONTROLS CARD */
.controls-card {
background: var(--ink);
color: var(--bg);
border-radius: 8px;
padding: 2rem;
margin-bottom: 2.5rem;
}
.controls-card h2 {
font-family: 'Fraunces', serif;
font-size: 1rem;
font-weight: 300;
font-style: italic;
color: rgba(245,242,235,0.5);
margin-bottom: 1.5rem;
letter-spacing: 0.03em;
}
.controls-grid {
display: grid;
grid-template-columns: 1fr 1fr;
gap: 1.25rem 2rem;
}
@media (max-width: 560px) {
.controls-grid { grid-template-columns: 1fr; gap: 1rem; }
}
.control-group label {
display: block;
font-size: 12px;
letter-spacing: 0.08em;
text-transform: uppercase;
color: rgba(245,242,235,0.45);
margin-bottom: 0.5rem;
font-weight: 400;
}
.control-group .val-row {
display: flex;
align-items: center;
gap: 10px;
}
.control-group input[type=range] {
flex: 1;
-webkit-appearance: none;
height: 3px;
background: rgba(245,242,235,0.15);
border-radius: 2px;
outline: none;
cursor: pointer;
}
.control-group input[type=range]::-webkit-slider-thumb {
-webkit-appearance: none;
width: 16px; height: 16px;
border-radius: 50%;
background: var(--bg);
cursor: pointer;
transition: transform 0.1s;
}
.control-group input[type=range]::-webkit-slider-thumb:hover { transform: scale(1.2); }
.control-group input[type=range]::-moz-range-thumb {
width: 16px; height: 16px;
border-radius: 50%;
background: var(--bg);
cursor: pointer;
border: none;
}
.control-group .val-display {
font-size: 1rem;
font-weight: 500;
color: var(--bg);
min-width: 80px;
text-align: right;
font-variant-numeric: tabular-nums;
}
/* STAT STRIP */
.stat-strip {
display: grid;
grid-template-columns: repeat(4, 1fr);
gap: 10px;
margin-bottom: 2.5rem;
}
@media (max-width: 600px) {
.stat-strip { grid-template-columns: 1fr 1fr; }
}
@media (max-width: 360px) {
.stat-strip { grid-template-columns: 1fr; }
}
.stat {
background: var(--bg2);
border: 1px solid var(--border);
border-radius: 6px;
padding: 1rem 1.1rem;
}
.stat-label {
font-size: 11px;
letter-spacing: 0.07em;
text-transform: uppercase;
color: var(--ink3);
margin-bottom: 0.35rem;
}
.stat-value {
font-size: 1.4rem;
font-weight: 500;
color: var(--ink);
font-variant-numeric: tabular-nums;
line-height: 1.2;
}
.stat-sub {
font-size: 12px;
color: var(--ink3);
margin-top: 0.2rem;
}
/* CHART SECTIONS */
.chart-section {
background: #fff;
border: 1px solid var(--border);
border-radius: 8px;
padding: 1.5rem;
margin-bottom: 1.25rem;
}
.chart-header {
display: flex;
align-items: flex-start;
justify-content: space-between;
margin-bottom: 1rem;
gap: 1rem;
flex-wrap: wrap;
}
.chart-title {
font-family: 'Fraunces', serif;
font-size: 1.1rem;
font-weight: 600;
color: var(--ink);
}
.chart-desc {
font-size: 13px;
color: var(--ink3);
margin-top: 2px;
}
.legend {
display: flex;
gap: 14px;
font-size: 12px;
color: var(--ink2);
flex-wrap: wrap;
align-items: center;
}
.legend span { display: flex; align-items: center; gap: 5px; }
.swatch {
width: 10px; height: 10px;
border-radius: 2px;
flex-shrink: 0;
display: inline-block;
}
.swatch.dashed {
background: linear-gradient(90deg, var(--sw-color) 50%, transparent 50%);
background-size: 6px 2px;
background-repeat: repeat-x;
background-position: center;
background-color: transparent;
height: 2px;
width: 18px;
border-radius: 0;
}
.chart-wrap {
position: relative;
width: 100%;
}
/* INSIGHT BOX */
.insight {
background: var(--bg2);
border-left: 3px solid var(--accent);
border-radius: 0 6px 6px 0;
padding: 1rem 1.25rem;
margin-bottom: 1.25rem;
font-size: 0.95rem;
color: var(--ink2);
line-height: 1.65;
}
.insight strong { color: var(--ink); font-weight: 500; }
/* EXPLAINER */
.explainer {
background: var(--bg3);
border: 1px solid var(--border);
border-radius: 8px;
padding: 1.75rem 2rem;
margin-top: 2rem;
}
.explainer h3 {
font-family: 'Fraunces', serif;
font-size: 1.2rem;
font-weight: 600;
margin-bottom: 1rem;
}
.explainer p {
font-size: 0.95rem;
color: var(--ink2);
margin-bottom: 0.75rem;
line-height: 1.7;
}
.explainer p:last-child { margin-bottom: 0; }
.explainer strong { color: var(--ink); font-weight: 500; }
/* FORMULA */
.formula-box {
background: var(--ink);
color: var(--bg);
border-radius: 6px;
padding: 1rem 1.25rem;
font-family: 'DM Sans', monospace;
font-size: 0.9rem;
margin: 1rem 0;
letter-spacing: 0.02em;
line-height: 1.8;
}
.formula-box span { color: #e8b4a0; }
/* STAMP */
.stamp {
display: inline-block;
position: relative;
margin-top: 2rem;
padding: 0.55rem 1.1rem;
border: 3px solid #e8b4a0;
border-radius: 4px;
font-family: 'Fraunces', serif;
font-size: clamp(0.75rem, 2.5vw, 0.95rem);
font-weight: 600;
letter-spacing: 0.12em;
text-transform: uppercase;
color: #e8b4a0;
opacity: 0.72;
transform: rotate(-4deg);
box-shadow: inset 0 0 0 2px rgba(232,180,160,0.18);
user-select: none;
}
.stamp::before {
content: '';
position: absolute;
inset: 3px;
border: 1px solid rgba(232,180,160,0.3);
border-radius: 2px;
pointer-events: none;
}
/* SMALL DIFF BANNER */
.small-diff-banner {
background: var(--accent);
color: #fff;
padding: 1rem 2rem;
display: flex;
align-items: flex-start;
gap: 0.75rem;
font-size: clamp(0.88rem, 2vw, 1rem);
line-height: 1.6;
}
.small-diff-banner strong { font-weight: 500; }
.sd-icon { font-size: 1.1rem; flex-shrink: 0; margin-top: 2px; }
/* FOOTER */
footer {
text-align: center;
padding: 2rem 1rem;
font-size: 12px;
color: var(--ink3);
border-top: 1px solid var(--border);
margin-top: 3rem;
}
footer a { color: var(--ink3); }
/* RESPONSIVE CHART HEIGHTS */
.h-240 { height: 240px; }
.h-200 { height: 200px; }
@media (max-width: 480px) {
.h-240 { height: 200px; }
.h-200 { height: 170px; }
.chart-section { padding: 1rem; }
main { padding: 1.5rem 1rem 3rem; }
.controls-card { padding: 1.25rem; }
.explainer { padding: 1.25rem; }
}