How to build a reliable family budget on one income (the system we used on $1,200/month in Taiwan)

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If you’ve ever Googled “how to budget on one income” or “family budget on one income” you’ve probably found advice written by people who consider $3,000 a month tight. This isn’t that kind of post.

For six years my wife and I lived on a missionary income in Taiwan. Somewhere between $1,200 and $1,500 a month (at the best $2,000), depending on what our supporters sent that month. We had rent to pay, food to buy, a scooter to run, utilities to cover, and we still gave, saved, and invested every single month without fail. Not because we were financial geniuses. Because we had a system and we stuck to it even when it was uncomfortable.

That system is what I want to walk you through today. It’s not complicated. It doesn’t require a finance degree or a big income. It requires honesty about your numbers and the willingness to tell every dollar where to go before the month begins. If we could make it work in Taiwan on a support-based missionary income, I promise you can make it work wherever you are.

We did it for six years in Taiwan. Through the early newlywed months, through the arrival of our first child, and now preparing to head into a new country with our second child due in one month. The system worked through all of it. Not because life was simple. Because the framework was solid.

Why one income budgeting or a family budget on one income is different

Family budget on one income isn’t just budgeting with less money. It’s budgeting with less margin for error.

When two people are bringing in income, a bad month for one can be absorbed by the other. An unexpected expense, a slow month, a job transition. There’s a buffer built into the structure. When you’re running on one income, that buffer doesn’t exist. Every dollar has to work harder because there simply aren’t as many of them.

That’s the reality my wife and I lived every single month in Taiwan. Our income wasn’t just one salary. It was support-based, which meant it varied. Some months we’d receive our full expected amount. Other months it came in short, or late, or in three separate installments across three weeks. We couldn’t plan around a fixed number. We had to build a system flexible enough to handle the variation while still covering everything that needed covering.

What we learned is that family budgeting on one income wasn’t about restriction. It was about intentionality. It’s about deciding in advance what matters, in what order, and making sure the most important things get funded first before the money has a chance to disappear into the gaps.

That pressure only grew when our first child arrived in 2022. Suddenly the budget wasn’t just covering two people, it was covering a family. A new category of expenses appeared almost overnight: diapers, formula, medical visits, baby gear. We didn’t overhaul the system. We adjusted the numbers within it. The framework held because the principles were sound regardless of the season of life we were in.

The family budget on one income framework we used: 50/30/20 budget rule with a twist

You may have heard of the 50/30/20 budgeting rule. The basic idea is simple. 50% of your income goes to needs, 30% to wants, and 20% to savings. It’s a solid framework. But when we tried to apply it in Taiwan, we quickly realized it needed a modification to reflect what actually mattered to us, reflected our needs as a family, and our varied income.

Our version looked like this:

I want to caveat this section that this framework’s percentages were not always strictly followed. These percentages were more like guidelines of how we allocated each month’s income. These percentages might not work for everyone, but what we want to emphasize is the mindset behind each category.

50% — Needs. Rent, utilities, groceries, transport. The non-negotiables. In Danshui this meant our apartment, our electricity and water bills, food from the wet market and the occasional night market meal, and keeping our scooter running. Everything that kept us alive and housed.

20% — Giving and saving. This is where our version diverged from the standard rule. We combined giving, supporting other missionaries and mission work with our emergency fund savings. Both came before wants. Both were non-negotiable. Giving first was a value we held deeply. Saving second was a discipline that protected everything else.

20% — Other. Everything else. This can be personal indulgences or just personal lifestyle choices that are not necessarily a “need,” but more like the small things that make life enjoyable. Maybe things like a coffee out, going to the movies, or a day trip on the weekend. Twenty percent sounds tight, but on a missionary budget in Taiwan it actually felt generous some months.

10% — Investing. Yes, even on $1,200 a month. Even when it felt almost absurd. We committed to putting something into our investment account every single month before the rest of the budget played out. Some months it was $30. Some months it was $50. The amount mattered less than the consistency. Because investing is as much about building a habit as it is about building wealth. A small amount done every month for six years looks very different from a large amount done occasionally.

Again, the most important part of this framework isn’t the percentages. It’s the order. This might look different for your family and this is something that you will need to discuss with your partner, but this framework was our family’s agreed upon order.

Needs first. Giving and saving second. Other/lifestyle third. Investments last. When you fund in that order, you never accidentally spend the savings money or investments because that money has its designated spot.

Another thing I want to add is that even though investments were given lower priority in this framework, personally its importance in our financial priorities were equal or even greater than our wants/other category. I will explain this more in a future post.

Your 7 one income budget categories broken down

Here’s how we broke our budget into categories every single month. These seven categories covered everything. Nothing fell through the gaps because everything had a home before the month began.

1. Housing / rent Your single largest expense and the first thing to fund. In Taiwan our rent was a significant portion of our budget. Aim to keep housing under 30% of your total income if at all possible. If it’s higher than that, everything else gets squeezed and the system struggles.

2. Food / groceries We kept this intentionally lean by shopping at traditional markets, cooking at home most nights, and treating eating out as an occasional want rather than a daily habit. A realistic target for a frugal family is 10–15% of income. Meal planning is your biggest ally, knowing what you’re cooking before you shop eliminates the expensive impulse decisions.

3. Transport In Taiwan this meant scooter fuel and occasional MRT fares. Remarkably cheap. In America this will likely mean a car payment, insurance, fuel, and maintenance. Transport costs have a way of creeping up. Assign a fixed monthly amount and treat any overage as a warning sign.

4. Utilities Electricity, water, internet, phone. These are largely fixed and predictable which makes them easy to budget. Track your average over three months and use that as your monthly allocation.

5. Giving (optional) This category might not be a value or priority for you, but it was for our family.

6. Savings / emergency fund Your financial safety net. Until you have three to six months of expenses saved, this category gets funded every single month without exception. Even a small amount, $20, $50, whatever the budget allows. Builds the habit and slowly builds the cushion. The month you need it you will be very glad it’s there.

7. Investing Fund this every month, no matter the amount. Automate it if you can, set up an automatic transfer on payday so the money moves before you have a chance to spend it. In our family this category was mine to manage. My wife trusted me with the investment decisions. But we agreed together that it would always be funded before anything discretionary. That shared commitment is what made the habit stick. As we covered in our investing on a small budget post, six years of small consistent deposits looks very different from six years of meaning to get around to it.

How to build your own one income budget in 5 steps

Here’s exactly how to build your own family budget on one income using this framework. Set aside 30 minutes, grab a cup of coffee, and work through these five steps.

Step 1 — Write down your total monthly income Start with what actually lands in your account after tax. Not what you earn but what you keep. This is your real number and your budget lives or dies by it.

Step 2 — List every fixed expense These are the amounts that don’t change month to month. Rent, loan repayments, insurance, subscriptions. Write them all down with their exact amounts. These come straight off the top of your income first.

Step 3 — Allocate your categories in order Using the 50/20/20/10 framework above, assign a dollar amount to each category in order. Needs first, giving and savings second, wants third, investing last. Use real numbers, not round ones. $340 for groceries is more honest than $300.

Step 4 — Give every remaining dollar a job Zero-based budgeting means your income minus your allocations equals zero. Every dollar is assigned somewhere before the month starts. If you have money left over after all categories are funded, assign it to savings, to investing, to a specific goal. Unassigned money evaporates.

Step 5 — Track it weekly A budget you set and never look at is just a wish list. Set a 10 minute weekly check-in. Every Sunday evening works well, to see where you stand in each category. Catching an overspend in week two gives you two weeks to correct. Catching it in week four leaves you nothing.

You can do this

The system isn’t complicated. It’s just consistent. We ran this budget on $1,200 a month in Taiwan for six years and it worked. Not because conditions were easy but because we were honest with our numbers and we funded what mattered before the money disappeared.

If you want to skip the setup time, use the free budget calculator. Just type in your income to start. You can also download the free one-page Family Budget Template based on exactly this framework through the form at the bottom of the calculator. It has all seven categories pre-built, the 50/20/20/10 allocations mapped out, and space for your real numbers. It only takes about 20-30 minutes to fill out!

And if you missed our first post, the full story of how we built these habits living as missionaries in Taiwan. You can read it here.