Monthly difference between rent and the savings you'd need for a mortgage deposit timeline.

1,200 rent a month, wanting a 50,000 deposit in 5 years with 4% return on savings, needs 754 a month of savings — about 63% of rent equivalent on top of paying rent. Total monthly housing-and-savings outflow: 1,955. Affordability ultimately depends on income; the tool shows the savings requirement so you can compare to realistic disposable income.

How to use it

Enter your current rent, target deposit amount, expected annual return (use 3-5% for cash savings in a high-interest account), and years to reach the deposit.

What the result means

Primary is monthly savings needed. Secondary rows show rent plus savings combined, the ratio of savings to rent, and total savings over the period. If savings-to-rent ratio is above 70%, the combined burden is high — most households find this uncomfortable to sustain.

What this doesn't handle

Income tax implications, tax-advantaged savings account wrapping, and variable rent. It also doesn't compare to buying-now scenarios — for that, use the rent-vs-buy calculator. This tool is specifically about the savings-while-renting phase.

A worked example

Try the defaults: monthly rent of 1,200, target deposit of 50,000, annual return of 4%, years to save of 5 years. The tool returns 754.16. You can adjust any input and the result updates as you type — no submit button, no reload. That's the real power here: seeing how sensitive the output is to one or two assumptions.

What moves the number most

The result responds to Monthly Rent, Target Deposit, Annual Return, and Years to Save. Not every input has equal weight. Flip one at a time toward extreme values to feel which ones move the needle most for your situation.

The formula behind this

Monthly savings required uses the ordinary annuity PMT formula with monthly compounding. The ratio of savings-to-rent is a heuristic for affordability strain: 50-70% means feasible but tight; above 70% usually requires income change or extending the horizon. Everything the calculator does is shown in the formula box below, so you can check the math against your own spreadsheet if you want.

Turning the result into a plan

A projection is just a starting point. The real work is setting the monthly amount aside automatically so the saving happens before you can spend it. Most people who hit savings goals set up a standing order on payday; most who miss them rely on willpower at month-end.

What this doesn't capture

The calculation assumes a steady savings rate and a stable interest rate. Real saving journeys include emergencies, windfalls, and rate changes — especially in easy-access products. The figure is a direction of travel, not a guarantee.