You turned 41, your pension is at £148,000 across two old workplace schemes, and you want to know whether you can retire at 60. Personal Capital can model that for a US household. Delphina can model it for a UK household. Here is the difference.
Personal Capital's Retirement Planner is one of the longer-standing free retirement tools in the US. It runs Monte Carlo simulations against your connected US accounts, models different withdrawal rates, and tests scenarios where you work longer, save more, or downsize your home. The "What-if" feature lets you adjust retirement age, monthly contribution and expected return and see the probability of success shift in real time. For a US household with $500k+ in qualified retirement accounts, the tool is genuinely useful.
The investment checkup is also strong. Personal Capital analyses your portfolio allocation, fees, and concentration risk, and flags holdings that are dragging returns. For US households with multiple brokerage accounts, this consolidation is hard to replicate elsewhere.
Delphina is built for the UK system: workplace pensions with salary sacrifice, SIPPs with 25% tax-free lump sum, ISAs (S&S, Cash, Lifetime, Junior), the State Pension forecast through your NI record, and the annual allowance taper that kicks in above £260,000 of adjusted income. Personal Capital does not model any of this correctly because the UK rules do not exist in its assumptions.
More importantly, Delphina's planning reads from your real spending. A 41-year-old with £148,000 in pensions, £35,000 in ISAs, and £2,400 a month going into savings gets a specific projection: their retirement date at their current pace, the gap to the UK moderate retirement number of around £580,000 for a single person, and the three or four monthly actions that close the gap fastest. Personal Capital requires you to enter a spending assumption and does not check whether the assumption matches your life.
Personal Capital's planning is best for US households optimising qualified retirement accounts. Its weakness is that the output is a probability, not a date. You see "84% chance of success" and have to decide what to do with it. Delphina gives you a date and shows you exactly what changes it.
If you have £300k+ across US retirement accounts, Personal Capital's investment checkup alone is worth the visit. If you are a UK household thinking about retirement in the next 20 years, Delphina gives you a more useful answer with less manual work.
Pull your State Pension forecast from your personal tax account on gov.uk and gather your two most recent pension statements. Connect both to Delphina this week. The exercise takes 20 minutes, and the gap between your position and the UK moderate retirement number becomes a single number you can plan around.