The savings-rate spreadsheet every household should keep

You don't need a personal-finance app to know your savings rate. You need a spreadsheet, ten minutes a month, and an honest accounting of what counts. Most households would be better off if they did this — and only this — than if they signed up for any tool, including ours.

This post is the case for the spreadsheet, the template we use, and the categorization edge cases that trip everyone up.

The formula

savings_rate = (take_home_income − total_spending) / take_home_income

Three columns in a Google Sheet, one row per month. Twelve rows per year. Annual average at the bottom. That's the whole instrument.

The categorization that matters

The math is simple. The arguments are about what counts as "saved" vs "spent."

• Pre-tax retirement contributions count as saved. A 401k contribution is not spending. If your employer matches, the match also counts (it's deferred compensation you'd otherwise be giving up).
• Mortgage principal counts as saved. Mortgage interest counts as spent. Most online savings-rate calculators get this wrong; most household budgets get it right intuitively. Track them separately if your mortgage statement combines them.
• Tax counts as spent. Even though you don't choose to spend it, you don't have it. If you're using gross income as the denominator (which we don't recommend), you're double-counting.
• Education savings (college funds, 529s) count as saved. They're for future spending but they're not spent now.
• Big one-offs are still spending. A new car, a wedding, a house renovation — all spending, even though the cash flow is unusual. Don't smooth them out; they tell you something about your real lifestyle.

The 35% personal threshold

Below 25% savings rate, you're working toward retirement slowly enough that you should think about earning more or spending less. Above 50%, you're FIRE-track if you keep it up for fifteen years. Between 25% and 50%, you're doing fine.

We pick 35% as the threshold to internalize because it has a useful property: at 35%, every year of working buys you one year of retirement. Below 35%, working slows your retirement timeline; above 35%, working accelerates it. It's the breakeven of work-versus-rest at typical real returns.

The spreadsheet

Three sheets. Inputs, monthly, summary.

1. Inputs sheet. Take-home pay (after tax, after pre-tax deductions), itemized monthly. Bonus rows included separately so they don't smooth your income line.
2. Monthly sheet. One row per month, one column per spending category. Pull from your bank statements once a month — twenty minutes the first time, ten minutes thereafter. Sum all spending categories into a single "spent" cell.
3. Summary sheet. Saving rate per month, plus rolling 3-month average, plus annual average, plus a chart of the trend.

That's it. Twelve rows × three sheets, one chart, and your single most important financial number for the next thirty years.

Why a spreadsheet beats most apps

Three reasons:

1. You see the categorization decisions. No black-box AI putting your kid's school fees in "Entertainment" because the merchant string was ambiguous. You decide every line.
2. It survives any tool migration. Apps come and go (Mint, Wesabe, Quicken Online, dozens of others). Your spreadsheet outlives them.
3. The act of doing it monthly is the value. Looking at every category, every month, with attention, is the part that changes behavior. Apps remove the attention by automating the categorization, which sounds like a win and isn't.

When a spreadsheet stops being enough

Three thresholds where you graduate from spreadsheet to tool:

• Multiple currencies. The math gets ugly fast when you're tracking AED, USD, GBP simultaneously. A spreadsheet with manual conversion works for two currencies; three is the breaking point.
• Investments more complex than "set and forget" index funds. Once you're tracking gains, distributions, lot-level cost basis, foreign withholding — a spreadsheet becomes a part-time job.
• FIRE forecasting. Monte Carlo over your actual portfolio is not a spreadsheet job. Excel can do it but you'll spend a weekend on it; a tool gives you a probability distribution in 200ms.

Until you hit one of those thresholds, the spreadsheet is the right tool. If you do hit them, that's where products like ours start earning their subscription.

We've published our actual savings-rate template — copyable Google Sheet — at our signup page for anyone who wants the structure. It's free, no email required.