Your Financial Runway Calculator: How to Know If You Can Actually Afford to Leave

You're thinking about leaving your job.

And immediately you think: "But I can't afford to."

But you haven't actually done the math. You're just assuming.

Here's a step-by-step guide to calculate your actual financial runway. To see exactly how many months you could live on your savings if you needed to.

Once you know this number, the decision becomes clearer.

Why This Matters

Most people massively underestimate their financial runway.

They think they need more savings than they actually do. They think they're more financially constrained than they are.

Once you know the real numbers, options appear that you didn't see before.

Maybe you can't leave tomorrow. But maybe you can leave in six months. Maybe you can leave part-time. Maybe you can leave if you find freelance work.

But you won't know until you do the math.

The Financial Runway Calculator

Step 1: Calculate Your Monthly Expenses

Go through every category and write down what you actually spend:

Housing:

• Rent/Mortgage: £___

• Council tax: £___

• Utilities (gas, electric, water): £___

• Internet/Phone: £___

• Home maintenance/repairs: £___

Total Housing: £___

Food:

• Groceries: £___

• Eating out: £___ (be honest)

• Coffee/drinks: £___

Total Food: £___

Transport:

• Public transport: £___

• Car payment (if applicable): £___

• Petrol/diesel: £___

• Car insurance: £___

• Parking: £___

Total Transport: £___

Health/Wellness:

• Gym/exercise: £___

• Therapy/counselling: £___

• Medications: £___

• Health insurance: £___

• Haircuts/personal care: £___

Total Health: £___

Insurance:

• Car insurance: £___ (already counted above)

• Home insurance: £___

• Life insurance: £___

• Travel insurance: £___

Total Insurance: £___

Childcare (if applicable):

• Nursery/childcare: £___

• School fees: £___

• Activities: £___

Total Childcare: £___

Debt Payments:

• Credit card minimums: £___

• Student loans: £___

• Personal loans: £___

• Medical debt: £___

Total Debt: £___

Subscriptions & Memberships:

• Streaming services: £___

• Software subscriptions: £___

• Gym: £___ (if separate)

• Memberships: £___

Total Subscriptions: £___

Discretionary Spending:

• Clothes/shopping: £___

• Entertainment/hobbies: £___

• Travel: £___

• Gifts: £___

Total Discretionary: £___

Other:

• Pet care/vet: £___

• Donations: £___

• Anything else: £___

Total Other: £___

YOUR TOTAL MONTHLY EXPENSES: £___

Important: This is your current spend, which might be higher than your survival spend.

Now calculate your survival spend (what you actually NEED to live on):

Remove discretionary items. Reduce where you can. What's the bare minimum you'd need?

YOUR MINIMUM MONTHLY EXPENSES: £___

Step 2: Calculate Your Available Resources

Current savings: £___

Partner's income (if applicable): £___ per month

Freelance/side income potential: £___ per month

Unemployment benefits (if eligible): £___ per month

Family support available: £___ (be realistic about this)

Assets you could sell (car, jewellery, etc.): £___

Credit available (credit cards, line of credit): £___ (only include if desperate)

Step 3: Calculate Your Runway

Savings ÷ Minimum Monthly Expenses = Months of Runway

Example:

• Savings: £15,000

• Minimum expenses: £2,000/month

• Runway: 7.5 months

Now add other income:

If you have part-time work, freelance work, or partner income available, add that:

Monthly expenses - Alternative income = Actual monthly burn

Example:

• Minimum expenses: £2,000

• Part-time freelance income: £800

• Actual monthly burn: £1,200

£15,000 ÷ £1,200 = 12.5 months of runway

Step 4: Adjust for Realistic Scenarios

Add a buffer: Most people recommend 20-30% buffer for unexpected costs.

Example: If your calculation says 12 months, plan for 9-10 months.

Account for transition time:

• 1-2 months: job searching, interviewing

• 1-2 months: transitioning from old job to new job (notice period)

• 1-2 months: settling into new job (reduced side income while adjusting)

Your realistic runway = Your calculated runway minus buffer and transition time

What Your Runway Actually Means

3-6 months:

• You have enough for a real career break or to find a new job

• Enough to take a part-time or lower-paid role and figure it out

• Enough to leave if you have other income (partner, freelance)

6-12 months:

• You have significant runway

• You can afford to be selective about your next move

• You can afford to leave without a new job lined up

• You could afford to take a lower-paying role you actually want

12+ months:

• You're in a very strong position

• You can afford career exploration

• You can afford to pivot

• You can afford to invest in training or skill-building

Less than 3 months:

• You have some runway but it's tight

• Best to find part-time work or new job before leaving

• Consider building runway before making big changes

The Runway Decision Framework

Once you know your runway, here's how to think about your options:

Option 1: Leave With No Plan

Requires: 12+ months runway (ideally)

This means: quit your job, take time to figure out what's next

Pros: Time to explore, reduce stress, rest

Cons: Anxiety about job searching, pressure to find something quickly

Option 2: Leave With a New Job

Requires: 1-2 months runway to cover notice period + transition

This means: find a new job while still employed, then transition

Pros: Continuous income, no stress, more selective about new role

Cons: Job searching while employed is hard, might settle for wrong role

Option 3: Leave for Part-Time Work

Requires: Enough runway to cover gap between current income and part-time income

Example:

• Current job: £4,000/month

• Part-time freelance: £1,500/month

• Gap to cover: £2,500/month

• Runway needed: depends how long you want to do this

Pros: Transition gradually, explore new directions, less financial pressure

Cons: Juggling two roles, still working

Option 4: Stay Employed and Build Runway

Requires: Time and discipline to save

This means: stay in your current job for 6-12 months while aggressively saving

Pros: Build financial security, more options for next move

Cons: Stay in job you hate longer, ongoing stress

Real Examples of Runway Calculations

Example 1: The Underpaid Employee

Current situation:

• Salary: £35,000

• Expenses: £2,200/month

• Savings: £8,000

Calculation:

• Runway: 3.6 months (way too tight)

• Options: Find new job while employed, or spend 6 months saving (get to ~£21,000, giving 9.5 months runway)

Decision: Build runway for 6 months, then leave with flexibility to be selective

Example 2: The Career Changer

Current situation:

• Salary: £55,000

• Expenses: £2,800/month

• Savings: £30,000

• Partner income: £2,500/month (covers most expenses)

Calculation:

• Runway: 10.7 months (plus partner income covers most costs)

• Options: Leave and transition into new field, knowing partner income covers basics

Decision: Leave in 2 months, take 8 months to retrain/transition into new career

Example 3: The Safety-Focused Professional

Current situation:

• Salary: £60,000

• Expenses: £2,500/month

• Savings: £50,000

• No partner income

Calculation:

• Runway: 20 months

• Options: Multiple paths available

Decision: Leave now to find aligned role, have plenty of runway to be selective

Common Runway Mistakes

Mistake 1: Forgetting taxes

If you're paid as self-employed or contractor, remember to set aside for taxes (usually 20-30%)

Mistake 2: Underestimating expenses

Most people spend more than they think. Track actual spending for 3 months before calculating.

Mistake 3: Overestimating side income

Don't count on freelance income until you've actually earned it consistently.

Mistake 4: Not including irregular expenses

Car repairs, medical bills, gift-giving. These add up. Include them in your calculation.

Mistake 5: Ignoring debt payments

If you have debt, you need to keep paying it. This reduces your runway.

What to Do With Your Runway Number

Once you know your runway, you can make actual decisions.

If You Have 3-6 Months Runway:

"I can leave if I find a new job, or take part-time work"

Action: Start job searching now. Don't wait.

If You Have 6-12 Months Runway:

"I can leave and have time to figure out what's next"

Action: Decide if you want to leave now or build more runway first.

If You Have 12+ Months Runway:

"I have real options. I can leave, explore, or invest in transition"

Action: Decide what you actually want to do with this time.

If You Have Less Than 3 Months Runway:

"I need to build runway before I leave"

Action: Set a savings target and timeline. Build runway aggressively.

The Real Question

Once you've done the math, the question changes from:

"Can I afford to leave?"

To:

"Am I willing to trade my current situation for X months of runway?"

And that's a different conversation entirely.

Because now it's not about money. It's about choice.

Frequently Asked Questions

Should I include debt payments in my expenses?

Yes. If you have ongoing debt payments, that's part of your actual monthly need.

What if my partner loses their job?

Good question. Don't count on partner income as your only buffer. Include it but have additional savings.

Should I include retirement contributions?

If you're leaving your job, probably not. You're not getting the company match anyway.

What about unexpected medical costs?

This is why the 20-30% buffer exists. Build it in.

Should I count my emergency fund as runway?

No. Your emergency fund stays separate. Runway is additional savings beyond that.

One More Thing

Once you know your runway, you might realise you can actually afford to ask for things you've been afraid to ask for.

Better working conditions. Flexibility. A raise. A different role.

Because you know you have options.

And knowing you have options changes everything.

Your Next Steps

This week:

Do the calculation. Spend an hour on it. Get the real number.

This month:

Decide: Do I have enough runway to make a change now? Or do I need to build runway first?

This quarter:

Act on that decision.

Final Thought

Stop guessing about money.

Do the actual math. See what's really possible.

Then make decisions based on reality, not fear.

Ready to make financial decisions confidently? Career Clarity Foundations includes guidance on aligning your financial situation with your career goals. Get clear on what's really possible, then make the move.