Are we planning our construction project realistically and healthily?

Hello dear experts,

We are currently about to purchase a plot of land and have our own home built on it. I would like to get opinions from you and see if our construction project is on solid ground.

About us
Woman (29), monthly net income: €2,300 full-time, permanent contract
Man (29), monthly net income: €3,700 full-time, permanent contract
One daughter (3) – further children are only planned when we move into the new home (probably end of 2021)
Equity: €150,000, which we are willing to put into the financing

To avoid going too much into the details of expenses, I only want to mention rough key points and our monthly savings amount.

Current rent including utilities: €1,300
2 cars, one of them paid off: monthly installment €250 for the next 3 years for the remaining car to be paid off

We can say about ourselves that we don’t really indulge in many extras and do not live beyond our means.
Monthly we save €2,500, which we do not touch, neither for vacations nor for other purchases. We already have the generally important insurances (disability insurance, health insurance, etc.).

About our construction project
We have already reserved a plot: €180,000 in Brandenburg
The house: We are still planning, probably 160 sqm for about €300,000
Additional costs: We cannot estimate. Rule of thumb 10-20%?
We plan to contribute mostly our own work for the outdoor facilities and painting.

Our absolute pain threshold is set at ~ €540,000.

I look forward to your expert opinions, as the two of us are complete laymen in this field.

Best regards and have a pleasant weekend!

Sounds very doable to me.
Equity + high savings rate

The construction costs for the house are certainly a bit tight at 300k.
But it also depends on the equipment.

Theoretically, it would be possible to finance a little more.
A rate of 1.5k to 1.75k should be no problem for you.

If it is your dream property: Then pay for it with equity.
Once the property is secured: Plan the house on it and save up equity.
If you can achieve 80% financing for the bank, secure good conditions for the loan.

Income is great.

Since the property counts as equity, you "only" have about 300,000 EUR + 100,000 EUR incidental costs = 400,000 EUR to finance. The 100,000 EUR is an approximate estimate (e.g., with a double garage for your two cars). But it also depends on the property.

Alright, you seem to have your finances under control