How Much Should You Save Before Investing? | My Benchmark for 'Setting Aside' Months of Living Expenses

📝 A Note of Disclaimer

The narrator of this note, “Mio,” is a guide character designed for those starting to invest with as little as 3,000 yen per month. The personal stories regarding family, household finances, and investment figures in this article are model cases (fictional) used for clarity and do not represent actual investment performance.

The person behind Mio usually trades stocks at SBI Securities. I will be sharing the actual stories and impressions of the person behind the scenes in future articles.

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※ This article is based on information as of September 29, 2026, and model cases (fictional). Investing carries the risk of loss of principal. Please make your own final decisions.

Good evening, this is Mio ☕

“How much savings do I need before I start investing?”

When I first thought about starting to invest, I was stuck on this question for weeks. I felt like I shouldn’t invest while my savings were low. But no one ever tells you exactly “how much is enough.”

In this article, I will talk about these three things:

・How I decided “how much to keep”
・A benchmark based on monthly living expenses (I made a quick reference table)
・Where to keep it, and where I stumbled

I am not an expert, so I would be happy if you read this as a record of “how I decided to do it” 🌱

Stuck on “Is it wrong to invest if I don’t have savings?”

When I looked it up, I saw many phrases like “Save first” and “Secure your living defense funds first.”

I understand that. But I couldn’t judge for myself whether my savings were high or low. While I was thinking “I should save more first,” about a year had passed 😅

Looking back now, what I was missing wasn’t savings, but a “ruler” to measure by.

The deciding factor was thinking in terms of “months of living expenses”

What got me moving when I was stuck was the method of thinking in terms of “how many months of living expenses” rather than a specific “amount of money.”

These are the figures often cited as benchmarks:

・Company employee households: 3 to 6 months of living expenses
・Self-employed or freelancers: 6 months to 1 year
・Households with children: A little more

It varies by household because the level of public support and the preparations needed when income stops are different.

This is where the three-category ‘relaxed household budget’ I mentioned before came in handy.

・Fixed costs (rent, communication expenses, insurance, etc.)
・Living expenses (food, daily necessities, etc.)
・Fun expenses (eating out, hobbies, rewards)

I used the total of ‘fixed costs + living expenses,’ which cannot be cut in an emergency, as my monthly living expenses. I did not include fun expenses because I can cut back on those when I’m in a pinch.

The guideline I decided on was ‘6 months of living expenses’

Being a cautious person, I chose the higher end of the guideline: ‘6 months’ worth’.

That said, I didn’t have that amount saved from the start. When I began investing, I had about 3 months’ worth. While investing 3,000 yen a month, I gradually increased it to 6 months’ worth using bonuses and other extra income.

‘If you have 3 months’ worth, you can start investing on a small scale’
‘Don’t increase your investment amount until you have 6 months’ worth’

Making these two things my own rules made me feel much more at ease. One of the ‘three things I checked before increasing to 5,000 yen’ that I wrote about in my previous article was exactly this.

I’ve created a table of guidelines based on monthly living expenses📊

Keep it in a separate place from your ‘everyday account’

Another important thing was where to keep the money.

Previously, my living expenses and savings were in the same account, and it was normal for the balance to just sort of dwindle away. Now, I move only the emergency money to a different account and try not to look at it in my daily life.

・Everyday account: Monthly living expenses
・Separate account: Emergency money (6 months of living expenses)
・Securities account: 3,000 yen per month from other money that I don’t need for daily life

Once I divided it into three, the anxiety that ‘investing might leave me short on living expenses’ disappeared. The money I’m investing is only the money that was in a separate box from the start. Just knowing that helped me stay calm even during months when my investments were down.

Where I stumbled

To be honest, when I first calculated it, I forgot to include annual payments.

Things like annual insurance premiums, car taxes, and annual subscriptions are expenses that don’t come out every month. When I divided those by 12 and added them in, my monthly living expenses were over 10,000 yen higher than I had thought😅

Also, there was a time when I tried to wait to invest until I had saved the target amount. But nothing started while I was waiting. My decision to ‘start small if you have 3 months’ worth’ came from this realization.

Summary: Think in terms of ‘how many months’ worth’ rather than just the amount

・Think of your savings goal in terms of “how many months of living expenses” you need.
・Calculate living expenses by adding your household budget’s “fixed costs + living expenses” to your annual payments divided by 12.
・Keep your emergency fund in a separate account from your daily spending account.

I used to think I couldn’t start until I had saved a large amount, but having this “yardstick” is what finally allowed me to take action.

How many months of living expenses do you use as a benchmark for your emergency fund? If you haven’t decided yet, please feel free to let me know in the comments! ☺️

※This article is based on information as of September 29, 2026, and a model case (fictional). The appropriate benchmark varies depending on your family’s situation. This is not a recommendation for any specific product or amount.