What is Networthify?
Networthify is a small site built around one question: when can I retire? Its main calculator asks for your after-tax income, how much you save, your expenses, your savings rate and what you have invested, with more options for the annual return and the withdrawal rate[1]. It answers with the number of years until you can retire, your goal net worth and a chart of how the answer changes at other savings rates. A year-by-year breakdown and a share button sit under the result.
The site's message is that your savings rate matters more than your income. A companion page shows two people who each save 50% of their pay, one earning $50,000 and one earning $200,000, retiring in the same 16.6 years, because the higher earner also needs a portfolio four times as large[2]. It is a clear, memorable way to show the idea, and it is why so many people search for the calculator by name.
Networthify is upfront about its simplifications. Under “Show assumptions” it lists four: your expenses now equal your expenses in retirement, you will never draw down the principal, income is after tax, and the return is after taxes and inflation[1]. Those assumptions are what keep it to a handful of inputs.
Around the calculator, the site adds context rather than more modeling. The result compares your savings rate with average household saving rates in several countries, from OECD figures, and the menu links to a page on how much people save by country and to a calculator for what recurring subscriptions really cost[1]. Everything points back to the same lesson: spend less, save the difference, and the date moves closer.
How do Networthify and FIRE Calculator Pro compare?
| Feature | Networthify | FIRE Calculator Pro |
|---|---|---|
| Main question | Years until you can retire, from your savings rate[1] | FIRE number, FI age and odds of success, plus Coast, Barista, Lean and Fat FIRE |
| Inputs | After-tax income, savings, expenses, savings rate, portfolio, return, withdrawal rate[1] | Age, pay, spending, savings, retirement spending, return, inflation, fees, stock mix, plan-until age |
| Default return | 5% after taxes and inflation[1] | 7% nominal, 3% inflation, 0.1% fees (3.79% real) |
| Retirement spending | Assumed equal to today's expenses[1] | Can differ from today's spending |
| Drawing down savings | Assumes the principal is never drawn down[1] | Models withdrawals to your plan-until age |
| Social Security or pension | No separate input[1] | Optional inputs with start ages |
| Risk tests | One fixed return[1] | 2,000-run Monte Carlo and every historical start year since 1928 |
| Account needed | No; the calculator runs on the page[1] | No |
Networthify details checked on its own pages in November 2026. FIRE Calculator Pro details are from our methodology page.
Do the two tools give the same answer?
On the core calculation, yes. The savings-rate method is simple: each year you add your savings to a portfolio that grows at a fixed real return, and you are done when the portfolio reaches your spending divided by the withdrawal rate. Networthify's default example saves $30,000 of a $50,000 after-tax income, a 60% savings rate, and shows 12.4 years to a goal of $500,000[1]. Our engine, given the same 5% real return and 4% withdrawal rate, gives 12.4 years.
The assumption that moves the answer most is the return. Networthify's 5% is after taxes and inflation. Our calculators default to 7% growth, 3% inflation and 0.1% fees, which comes to 3.79% after inflation. The table shows years to FI at several savings rates under each, plus a more cautious 3.5% withdrawal rate.
| Savings rate | 5% real, 4% withdrawal | 3.79% real, 4% | 5% real, 3.5% |
|---|---|---|---|
| 10% | 51.3 years | 60.6 years | 53.9 years |
| 25% | 31.9 years | 36.2 years | 34.1 years |
| 50% | 16.6 years | 17.9 years | 18.2 years |
| 60% | 12.4 years | 13.2 years | 13.7 years |
| 75% | 7.1 years | 7.4 years | 8 years |
Our calculation with the FIRE Calculator Pro engine, starting from a $0 portfolio, with spending equal to income minus savings.
At high savings rates the return barely matters: at 75% the gap is 0.2 years. At low savings rates it matters a great deal, because most of the final portfolio comes from growth rather than from what you put in. The withdrawal rate works the other way: moving from 4% to 3.5% raises the goal by a seventh, which adds 1.3 years at a 60% savings rate.
Why the savings rate carries so much weight
The savings rate works on both sides of the equation at once. Every dollar you save is a dollar added to the portfolio and a dollar you have shown you can live without, which lowers the goal. That is why, with a starting balance of zero, income drops out of the answer. In our engine a 50% savings rate at 5% real and a 4% withdrawal rate takes 16.6 years whether you earn $50,000 or $200,000, the same result Networthify shows on its income comparison page[2].
Savings you already have break that symmetry. They are measured against your spending, so a head start counts for more on a lower budget. Starting the default example with $50,000 already invested, one year of take-home pay, the time to FI at a 60% savings rate falls from 12.4 years to 10.8 years in our engine. Networthify has a portfolio value field for exactly this[1].
What happens once you start withdrawing?
Networthify's assumption that you never draw down the principal[1] follows from its inputs. If the portfolio earns a steady 5% after inflation and you withdraw 4%, it grows every year on paper. Real markets do not deliver 5% every year, and a bad decade early in retirement can do lasting damage even if the long-run average is fine[6].
So we took the default plan one step further. Saving $30,000 a year from age 30 at 5% reaches the goal at 43 in our engine. We then retired the plan at 43 with exactly the goal, spending $20,000 a year in today's dollars until 95, a 52-year retirement, and tested it two ways: a replay of every historical start year with a full 52-year record, and 2,000 Monte Carlo runs.
| Portfolio at 43 | Historical | Monte Carlo | Monte Carlo, 5% matched |
|---|---|---|---|
| $500,000 at 4% (Networthify's goal) | 77% | 78% | 66% |
| $571,429 at 3.5% | 94% | 86% | 76% |
| $500,000 at 4%, plus $15,000/yr Social Security from 67 | 96% | 91% | 85% |
Our calculation: 80% stocks and 20% bonds, 0.1% fees, US data 1928-2025[3]. Historical: 47 start years. Monte Carlo: 2,000 runs, seed 2026, replaying history or shifted so its average real return is 5%.
The two tests answer slightly different questions. The historical replay asks what would have happened to someone who retired in each past year, with markets arriving in their real order. The Monte Carlo run builds 2,000 new sequences by drawing those same years at random, and the matched version first shifts every year so the long-run average equals the 5% you assumed, which keeps the comparison with Networthify fair.
A 4% withdrawal rate held up in about 77% of historical start years over 52 years. The worst start, 1966, ran out of money after 25 years. That is in line with research showing that 4% was built for 30-year retirements[4] and that longer early retirements call for something closer to 3.25%-3.5%[5]. At 3.5% the same plan held up in 94% of start years, at the cost of 1.3 years more saving.
Social Security changes the picture again. A $15,000 benefit from 67 means the portfolio only has to cover $5,000 a year from then on. In our engine that lowers the amount needed at 43 to $376,340 and brings the FI age to 41. Kept at $500,000, the plan with the benefit held up in 96% of historical start years. Your own estimate is available from the Social Security Administration[7].
How do you check a Networthify result here?
If you have a Networthify answer, you can re-create it in our FIRE calculator and then add what it leaves out. The fields line up like this:
- After-tax income and expenses. Enter them as take-home pay and spending per year. The calculator shows the savings rate they imply, so you can check it matches.
- Portfolio value. Enter it as what you have invested today.
- Return. Networthify asks for a return after inflation[1], while we ask for a nominal return, inflation and fees separately. To reproduce its 5%, enter 8.15% growth with 3% inflation and no fees. Then try our defaults to see how sensitive your date is.
- Withdrawal rate. Use the same rate. Then set the age your money must last until; for an early retirement, 95 means a horizon of 50 years or more.
- What Networthify does not ask. Add your Social Security estimate and claiming age, and switch on a different retirement budget if your spending will change, for example after the mortgage is paid off.
With those inputs our deterministic answer should land within a year of Networthify's, because the timing conventions differ slightly. The new information is below the result: a Monte Carlo success rate, the share of historical start years that worked, and the worst ones.
When should you use Networthify instead?
- You want one number fast. Five inputs and one button, with the answer and a savings-rate chart on the same screen[1].
- You are deciding how much to save. Clicking the chart to try other savings rates is a quick way to feel the trade-off.
- You are explaining FIRE to someone. The income comparison page makes the savings-rate idea easy to grasp[2].
When should you use FIRE Calculator Pro?
- Your retirement spending will differ from today's. Enter them separately, for example once the mortgage is paid off.
- You expect Social Security or a pension. Income that starts later lowers your target from the age it begins.
- Your retirement could last 40 years or more. Set the age the money must last to and see how often your withdrawal rate held up.
- You want to stress-test the plan. Every FIRE calculator shows a Monte Carlo success rate and the worst historical start years, and you can switch the tests to match your own return assumption.
- You want to go further. Coast, Barista, Lean and Fat FIRE calculators use the same engine, so the answers are consistent.
A good way to use both: find your savings-rate answer on Networthify, then put the same numbers into our FIRE calculator and see how much margin the plan has. The formulas are documented on the methodology page.