ApexGap Engine
shippedA free CPF retirement gap calculator for Singaporeans.
Why it exists
Most people in Singapore have a rough sense that CPF alone might not cover retirement, but no clear number to act on. I built ApexGap so anyone can run the numbers themselves, see how CPF, SRS, and cash investment interact, and leave with something concrete.
Features
See your retirement gap in minutes
Enable CPF, SRS, or cash investment streams, dial in your age and target monthly income. A single gap number, a full wealth timeline, and a Monte Carlo probability score appear immediately. 1,000 simulations run in the browser to show the likelihood your savings survive to your plan horizon. No sign-in, no account.
Model every income stream independently
Toggle CPF OA, SRS, and cash investment as separate streams; each adjusts in real time. The summary shows a side-by-side CPF LIFE plan comparison (Standard, Escalating, Basic) with monthly payouts at 65 and 85 and lifetime totals, so picking a plan is a real decision, not just the default.
Concrete moves, not just a gap number
The summary breaks the gap down by income source and shows specific actions: the exact monthly CPF top-up to close it, an SRS contribution scenario, the required savings rate. Each move shows how much it shifts the number. You can also export the full report as a PDF.
Test every assumption before you commit
Four built-in sensitivity panels let you stress-test the plan: run longevity to age 100, push inflation to 5%, delay retirement by 1, 3, or 5 years, and adjust monthly spending by ±S$500. Each panel recalculates instantly and shows the new gap.
Singapore statutory logic, built in
CPF LIFE plan structures, OW ceilings, BRS/FRS/ERS thresholds, and SRS caps are baked in and reviewed annually. Clearly marked as illustrative and not financial advice.
Why I built it
Most people in Singapore have a rough sense that CPF alone might not cover retirement, but no number to act on. The tools that exist are either buried in adviser platforms or require a login before you see anything. I wanted to make the calculation available to anyone, in the browser, with no friction.
What I worked on
The build was done with AI tools. The financial model was mine to get right. CPF LIFE works a specific way depending on the plan you pick, SRS has its own drawdown logic, and the interaction between streams matters a lot to the final number. Getting all of that correct and keeping the tool honest about what it can and cannot tell you is where my background in finance mattered.
ApexGap went through three versions before the current one. It started as a Telegram Mini App: instant distribution, no App Store friction, identity without passwords. That worked until it hit Telegram’s sandbox limits: no payment flows, no PWA install, no offline support. It then moved to a standalone B2B SaaS with tiered access, FA presentation mode, and a session audit trail, more surface area than the problem needed. The V5.0 pivot removed the login gate entirely and made every calculation local. The two prior architectures were not wasted. The financial model got stress-tested across real planning sessions, and the compliance ground rules from the B2B phase (MAS FAA-N16 rate caps, illustrative disclaimers) carried into the public version unchanged.