Stairlift Weight Capacity Explained | Standard, Heavy-Duty & Limits

Short answer: a standard UK stairlift takes 19 stone (120 kg), a heavy-duty stairlift takes 25 stone (160 kg), and bariatric models go up to 30 stone (190 kg). The limit covers the user only — not their clothes, mobility aids or anything they're carrying — so it pays to leave a sensible margin.

Standard weight limits by category

All limits are set by the manufacturer and certified to BS EN 81-40, the UK and European safety standard for stairlifts.

Why the limits matter

A stairlift's weight rating isn't a guideline — it determines the safe loading on the rail, brackets, motor, drive system and brakes. Exceeding it risks:

• Drive slip on the climb — the motor stalls and the lift halts mid-stairs
• Premature brake wear — particularly on the descent
• Battery undervoltage — heavier loads draw more current and shorten range
• Frame fatigue — over months and years, components designed for 120 kg under repeated 140 kg loads will fail early

If the user is close to or over the standard limit, fitting a heavy-duty model from day one is always the safer call.

Choosing the right model

• Up to 18 stone (115 kg) — a reconditioned Acorn 130 at £995 is the most affordable option.
• 18–19 stone (115–120 kg) — a new standard straight or curved lift comfortably handles the load.
• 19–25 stone (120–160 kg) — heavy-duty models. The Acorn 130 HD (straight) and the Infinity heavy-duty range are designed for this band.
• 25–30 stone (160–190 kg) — bariatric stairlifts. Specialist install — wider seat, reinforced rail, additional bracket points. Quoted on survey.

We'd always rather oversize the lift slightly than fit a standard model that's close to its rated limit.

Things that count toward the limit

Manufacturer limits cover the user only. If the user typically carries items up the stairs (a laundry basket, a pet, an oxygen cylinder), those weights count against the rating too. Sensible practice: take 10–15 kg off the rated limit as a usable budget.

For users near the upper limit, also factor in:

• Winter clothing (1–2 kg)
• Mobility aid like a folded walking stick or rollator stowed beside (1–3 kg)
• Comfort cushion or seat overlay (1–2 kg)

Width and seat dimensions

Larger users sometimes need more shoulder and hip room as well as a higher weight rating. Heavy-duty seats are typically 50–55 cm wide (vs 42–46 cm on a standard lift) with stronger armrests and a wider footrest. The seat width is usually the comfort factor that matters most day-to-day.

What the survey checks

The home survey isn't just measuring the stairs — for higher-weight users we also confirm:

• Tread integrity — the timber needs to take the loaded bracket points
• Bracket spacing — heavy-duty installations use closer-spaced brackets
• Headroom and transfer space — heavy-duty seats are larger
• Charging point placement — heavier loads benefit from charging at both ends

No structural work is needed on a sound staircase, but rotten or split treads must be repaired before fitting.

Pricing for higher-capacity lifts

Heavy-duty and bariatric models cost more than standard — the components are bigger and the install takes longer. We quote a fixed price after the survey rather than publishing a range, because the right model depends on the user's weight, height, mobility and staircase. Most heavy-duty installs come in between £3,000 and £4,500 all-in.

If you're not sure

Be honest with the surveyor about the user's weight — it's the single most important piece of information for picking the right model. Specifying low to "keep the price down" leads to a lift that wears out fast or stalls on the climb; specifying high just means a slightly larger seat and a properly sized motor.

Call 0161 330 5544 and we'll talk you through the right model for the user's weight and your staircase, and book a free home survey.

Our fixed prices

All prices include the free home survey, installation, handover and a 12-month warranty.

Our stairlifts

• Straight stairlifts — £1,995 fitted
• Curved stairlifts — £2,995 fitted
• Reconditioned stairlifts — £995 fitted
• Outdoor stairlifts
• Servicing & repairs

Book a free home survey

Call 0161 330 5544 or request a callback. A local engineer will measure your stairs and give you a fixed price on the day — no pressure, no obligation.