Retirement Savings Calculator

How much will I have at retirement with my contributions and employer match?

Single calculationv1.0.0Verified 2026-11-01Runs in your browser

Spec sheet

fv_contrib_match · v1.0.0

Method

Future value of balance + monthly contributions (numpy-financial fv)

01monthly in = contribution × (1 + match %)
02balance = −fv(r/12, 12·years, −monthly in, −current)
03income ≈ 4 % of balance per year (guideline)

Limits — read before relying on it

Nominal dollars; use a real (after-inflation) return to see today's purchasing power.
No contribution limits, taxes or fees.
The 4 % rule is a planning guideline, not a guarantee.

Sources

numpy-financial (BSD-3) — ported to TypeScript ↗library

Worked example

computed by the same formula

Age 35, $50k saved, $500/mo, 50 % match

Inputs

Current age: 35
Retirement age: 65
Current savings: 50000
Your monthly contribution: 500
Employer match (% of your contribution): 50 %
Expected annual return: 6 %

Result

Balance at retirement: $1,054,515.04
Total contributed (you + employer): $320,000.00
Investment growth: $734,515.04
Annual income at 4 % withdrawal: $42,180.60

Questions

How is the retirement savings calculated?

›

Future value of balance + monthly contributions (numpy-financial fv). monthly in = contribution × (1 + match %) · balance = −fv(r/12, 12·years, −monthly in, −current) · income ≈ 4 % of balance per year (guideline)

Example: Age 35, $50k saved, $500/mo, 50 % match?

›

Balance at retirement: $1,054,515.04; total contributed (you + employer): $320,000.00.

What does this calculator not cover?

›

Nominal dollars; use a real (after-inflation) return to see today's purchasing power. No contribution limits, taxes or fees. The 4 % rule is a planning guideline, not a guarantee.

Where do the numbers come from?

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Sources: numpy-financial (BSD-3) — ported to TypeScript. The formula is versioned (fv_contrib_match v1.0.0) and covered by automated tests.

Is my data stored?

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No. The calculation runs in your browser and nothing is sent unless you choose to save a shareable link.

Also searched asretirement calculator · 401k calculator · how much will i have at retirement · retirement savings with employer match · retirement planning

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