Measure once. See how the canvas will sit.
Worked example: 16 × 24 inch canvas, 0.25 inch gap, 0.5 inch frame face.
Your floater-frame measurements
An even shadow gap on all four sides.
- Canvas (supplier artwork size)
- 16 × 24 in
- Actual inside opening
- 16.5 × 24.5 in
- Finished outside footprint
- 17.5 × 25.5 in
- Gap at left and right, each
- 0.25 in
- Gap at top and bottom, each
- 0.25 in
Depth: Depth not checked. Measure the canvas and the frame’s usable depth before ordering. Usable depth is measured from the canvas support surface to the front rim; mounting pads or spacers change this position.
Before ordering: If the supplier asks for canvas size, give 16 × 24 in and specify the reveal separately. Use 16.5 × 24.5 in only when asked for the actual inside opening. Do not add the gap twice.
Centred, rectangular canvas and equal frame-face widths assumed. Negative gaps mean overlap. Measurements are rounded to 0.001 in; this is a geometry check, not a mounting or manufacturing tolerance guarantee. Confirm squareness, supports and hardware with the framer.
Measurements stay on this page. Analytics count usage and fixed fit categories, never the sizes you enter.
Find a portrait for your wall — browse canvas styles →Canvas size, opening size and outside size are different
A floater frame surrounds a stretched canvas with a visible shadow gap. For a centred canvas, add the gap twice to each canvas dimension to find the actual inside opening. Add the visible frame face twice more to find the finished footprint on your wall. The frame face is the narrow rim you see from the front, not the hidden support ledge beneath the canvas.
For example, a 16 × 24 inch canvas with a 0.25 inch gap on each side needs a 16.5 × 24.5 inch opening. A 0.5 inch frame face makes the outside 17.5 × 25.5 inches. These are calculated measurements, not a catalogue size or a promise that a particular frame will fit.
Do not add the shadow gap twice when ordering
Check what the supplier means by “frame size”. Some ask for your canvas dimensions and add the reveal themselves. Web Picture Frames’ sizing guide asks for the artwork size and a separate reveal choice. EasyFrame’s measuring guide also starts with the canvas measurements and adds a gap when that option is selected. Give the calculated opening only to a supplier who explicitly asks for the actual inside opening.
Measure the stretched canvas itself, including any bulging corners, rather than relying on its printed size label. Compare the diagonals to check that it is square. A rectangular calculation cannot account for a warped stretcher or an out-of-square frame.
Check the depth before choosing a floater frame
Usable frame depth runs from the surface supporting the back of the canvas to the front rim. Subtract canvas depth to see how far the canvas front will sit behind that rim; a negative result means it will project ahead. Mounting pads or spacers lift the canvas and change this position. Leave both depth fields empty if you have not measured them yet.
This calculator helps you plan an optional decorative frame. For a paper print with a mat, use the mat size calculator. Choose a finish with the frame color matcher, then place the finished footprint with the portrait size guide. PortraitGift’s gallery-wrapped canvases can be displayed without an outer floater frame.
How it works
- Choose inches or centimetres and enter the measured canvas width and height. Use decimal measurements, such as 0.25 for a quarter inch.
- Plan a new opening with a gap per side, or enter the actual inside opening of a frame you own. Add its visible face width and, optionally, both depth measurements.
- Calculate to see the diagram, gaps and finished footprint. Copy the plan, then confirm the supplier’s sizing convention and mounting requirements before ordering.
Frequently asked questions
What size floater frame do I need for a 16 × 24 canvas?
With a quarter-inch gap on every side, the actual inside opening is 16.5 × 24.5 inches. If the seller sizes frames by the canvas they fit, select 16 × 24 and specify the gap separately. The finished outside size also depends on the frame face width.
How much gap should I leave around the canvas?
The gap is a design choice and depends on the frame system. This tool starts at 0.25 inch per side as an editable example. Confirm the available reveal and allowances with your supplier; there is no universal gap that guarantees a fit.
Can I check a floater frame I already own?
Yes. Choose “Check an existing frame” and measure the actual clear inside width and height at the canvas edge. The calculator halves each opening-minus-canvas difference to find the centred gaps. Zero or negative gaps flag that the canvas touches or overlaps the opening.
Does the canvas depth have to match the frame depth?
Equal canvas depth and usable frame depth put the front surfaces flush in this model. A deeper frame recesses the canvas; a shallower frame lets it project. This assumes the canvas back rests on the support surface without spacers. Confirm the mounting system with the framer.
Does this calculator make a woodworking cut list?
No. It calculates finished dimensions and clearance. It does not account for joints, saw cuts, moulding profiles, support ledges or mounting hardware. Take the measurements to your framer or use a construction plan suited to your chosen moulding.
Is the tool free, and are my measurements saved?
The calculator and copyable plan are free, with no signup or upload. Measurements stay in this page’s memory and are not saved or sent in analytics. Usage analytics receive only fixed categories such as calculation mode and fit verdict.
Find a portrait for your wall — browse canvas styles →